[Federal Register Volume 81, Number 49 (Monday, March 14, 2016)]
[Proposed Rules]
[Pages 13451-13528]
[FR Doc No: 2016-05493]

Vol. 81

Monday,

No. 49

March 14, 2016

Part II

Department of Transportation

-----------------------------------------------------------------------

 Federal Aviation Administration

-----------------------------------------------------------------------

14 CFR Parts 21, 23, 35, et al.

 Revision of Airworthiness Standards for Normal, Utility, Acrobatic,
and Commuter Category Airplanes; Proposed Rule

Federal Register / Vol. 81 , No. 49 / Monday, March 14, 2016 /
Proposed Rules

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 21, 23, 35, 43, 91, 121, and 135

[Docket No.: FAA-2015-1621; Notice No. 16-01]
RIN 2120-AK65

Revision of Airworthiness Standards for Normal, Utility,
Acrobatic, and Commuter Category Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to amend its airworthiness standards for
normal, utility, acrobatic, and commuter category airplanes by removing
current prescriptive design requirements and replacing them with
performance-based airworthiness standards. The proposed standards would
also replace the current weight and propulsion divisions in small
airplane regulations with performance- and risk-based divisions for
airplanes with a maximum seating capacity of 19 passengers or less and
a maximum takeoff weight of 19,000 pounds or less. The proposed
airworthiness standards are based on, and would maintain, the level of
safety of the current small airplane regulations. Finally, the FAA
proposes to adopt additional airworthiness standards to address
certification for flight in icing conditions, enhanced stall
characteristics, and minimum control speed to prevent departure from
controlled flight for multiengine airplanes. This notice of proposed
rulemaking addresses the Congressional mandate set forth in the Small
Airplane Revitalization Act of 2013.

DATES: Send comments on or before May 13, 2016.

ADDRESSES: Send comments identified by docket number FAA-2015-1621
using any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the online instructions for sending your
comments electronically.
     Mail: Send comments to Docket Operations, M-30; U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE., Washington, DC, between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at<PHONE_NUMBER>.
    Privacy: In accordance with 5 U.S.C. 553(c), DOT solicits comments
from the public to better inform its rulemaking process. DOT posts
these comments, without edit, including any personal information the
commenter provides, to www.regulations.gov, as described in the system
of records notice (DOT/ALL-14 FDMS), which can be reviewed at http://www.dot.gov/privacy.
    Docket: Background documents or comments received may be read at
http://www.regulations.gov at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE.,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning
this action, contact Lowell Foster, Regulations and Policy, ACE-111,
Federal Aviation Administration, 901 Locust St., Kansas City, MO 64106;
telephone<PHONE_NUMBER>; email<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Later in this preamble, under the Additional
Information section, we discuss how you can comment on this proposal
and how we will handle your comments. This discussion includes related
information about the docket, privacy, and the handling of proprietary
or confidential business information. We also discuss how you can get a
copy of this proposal and related rulemaking documents.
    All sections of part 23 would contain proposed revisions, except
the FAA would not make any substantive changes to the following
sections: Sec. Sec.  23.1457, Cockpit Voice Recorders, and 23.1459,
Flight Data Recorders. The only proposed changes to Sec.  23.1459 would
be for the purpose of aligning part 23 references. These sections are
nevertheless included in this proposed revision for context.

Table of Contents

I. Executive Summary
    A. Purpose and History of the Proposed Performance-Based
Standards
    B. Summary of Major Provisions
    1. Performance Standards and Airplane Crashworthiness
    2. Loss of Control
    3. Icing Certification Standards
    C. Cost and Benefits
II. Authority for This Rulemaking
III. Background
    A. Part 23 History
    B. New Safety Requirements
    C. Benefits for the Existing Fleet
    D. Conforming Amendments and Other Minor Amendments
    E. Public Policy Implementation
    1. Regulatory Planning and Review
    2. Consensus Standards
    3. International Cooperation Efforts for Reorganizing Part 23
    F. Means of Compliance
    G. FAA Strategic Initiatives
IV. Discussion of Proposal
    A. Reorganization of Airworthiness Standards Based on Risk and
Performance
    B. Introduction of Simple Airplanes
    C. Establishing Performance-Based Standards and the Use of Means
of Compliance
    D. Crashworthiness as an Illustration of the Benefits of
Performance-Based Regulations
    E. Additional Requirements To Prevent Loss of Control
    F. Additional Requirements for Flight in Icing Conditions
    G. Production of Replacement and Modification Articles
V. Key Terms and Concepts Used in This Document
VI. Discussion of the Proposed Regulatory Amendments
    A. Part 23, Airworthiness Standards
    1. Subpart A--General
    2. Subpart B--Flight
    3. Subpart C--Structures
    4. Subpart D--Design and Construction
    5. Subpart E--Powerplant
    6. Subpart F--Equipment
    7. Subpart G--Flightcrew Interface and Other Information
    8. Appendices to Part 23
    B. Miscellaneous Amendments
    1. Production of Replacement and Modification Articles (Sec.
21.9)
    2. Designation of Applicable Regulations (Sec.  21.17)
    3. Issuance of Type Certificate: Primary Category Aircraft
(Sec.  21.24)
    4. Flight Tests (Sec.  21.35)
    5. Instructions for Continued Airworthiness and Manufacturer's
Maintenance Manuals Having Airworthiness Limitations Sections (Sec.
21.50)
    6. Designation of Applicable Regulations (Sec.  21.101)
    7. Applicability (Sec.  35.1)
    8. Fatigue Limits and Evaluation (Sec.  35.37)
    9. Altimeter System Test and Inspection (Appendix E to Part 43)
    10. Powered Civil Aircraft With Standard Category U.S.
Airworthiness Certificates: Instrument and Equipment Requirements
(Sec.  91.205)
    11. Restricted Category Civil Aircraft: Operating Limitations
(Sec.  91.313)
    12. Increased Maximum Certification Weights for Certain
Airplanes Operated in Alaska (Sec.  91.323)
    13. Second In Command Requirements (Sec.  91.531)
    14. Additional Emergency Equipment (Sec.  121.310)
    15. Additional Airworthiness Requirements (Sec.  135.169)

VII. Regulatory Notices and Analyses
    A. Regulatory Evaluation Summary
    B. Initial Regulatory Flexibility Determination
    C. International Trade Impact Assessment
    D. Unfunded Mandates Assessment
    E. Paperwork Reduction Act
    F. International Compatibility and Cooperation
    G. Environmental Analysis
    H. Regulations Affecting Intrastate Aviation in Alaska
VIII. Executive Order Determination
    A. Executive Order 13132, Federalism
    B. Executive Order 13211, Regulations That Significantly Affect
Energy Supply, Distribution, or Use
IX. Additional Information
    A. Comments Invited
    B. Availability of Rulemaking Documents
Appendix 1 to the Preamble--Current to Proposed Regulations Cross-
Reference Table
Appendix 2 to the Preamble--Abbreviations and Acronyms Frequently
Used In This Document

I. Executive Summary

A. Purpose and History of the Proposed Performance-Based Standards

    Part 23 of Title 14 of the Code of Federal Regulations (14 CFR)
prescribes airworthiness standards for issuance and amendment of type
certificates for airplanes with a passenger-seating configuration of 19
or less and a maximum certificated takeoff weight of 19,000 pounds or
less. Airplanes certificated under part 23 are typically used for
recreation, training, personal travel, and limited commercial
applications.
    The current part 23 airworthiness standards are largely
prescriptive, meaning that they describe detailed design requirements,
and are based on airplane designs from the 1950's and 1960's. As a
result of this prescriptive framework, the FAA often requires a design
approval applicant seeking to incorporate new or innovative technology
to provide additional documentation that typically results in the FAA's
issuance of special conditions, exemptions, or equivalent level of
safety (ELOS) findings.\1\ The FAA recognizes that these additional
procedures and requirements are costly to the FAA and industry, act as
barriers to certification, and discourage innovation. Therefore, to
encourage the installation of new safety-enhancing technology and
streamline the certification process, the FAA proposes replacing the
prescriptive requirements found in the current part 23 with
performance-based standards.
---------------------------------------------------------------------------

    \1\ Special conditions give the manufacturer permission to build
the aircraft, engine or propeller with additional capabilities not
addressed in the regulations. A petition for exemption is a request
to the FAA by an individual or entity asking for relief from the
requirements of a regulation. Equivalent level of safety findings
are made when literal compliance with a certification regulation
cannot be shown and compensating factors exist which can be shown to
provide an equivalent level of safety. 14 CFR parts 11 and 21
provides information on special conditions and exemptions. FAA Order
8110-112A provides standard procedures for issue paper and
equivalent level of safety memoranda.
---------------------------------------------------------------------------

    The FAA believes this proposed rulemaking would maintain the level
of safety associated with current part 23, while providing greater
flexibility to applicants seeking certification of their airplane
designs. By doing so, this proposed rulemaking would hasten the
adoption of safety enhancing technology in type-certificated products
while reducing regulatory time and cost burdens for the aviation
industry and FAA. This proposed rulemaking would also reflect the FAA's
safety continuum philosophy,\2\ which balances the need for an
acceptable level of safety with the societal burden of achieving that
level safety, across the broad range of airplane types certificated
under part 23.
---------------------------------------------------------------------------

    \2\ The FAA's safety continuum philosophy is that one level of
safety may not be appropriate for all aviation. The FAA accepts
higher levels of risk, with correspondingly fewer requirements for
the demonstration of compliance, when aircraft are used for personal
transportation.
---------------------------------------------------------------------------

    This proposed rulemaking is the result of an effort the FAA began
in 2008 to re-evaluate the way it sets standards for different types of
airplanes. Through this effort, a joint FAA and industry team produced
the Part 23 Certification Process Study \3\ (CPS), which reviewed the
life cycle of part 23 airplanes to evaluate certification processes and
develop recommendations. Two key recommendations were to (1) reorganize
part 23 based on airplane performance and complexity rather than the
existing weight and propulsion divisions, and (2) permit the use of
consensus standards as a means to keep pace with rapidly increasing
design complexity in the aviation industry.
---------------------------------------------------------------------------

    \3\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    In 2010, with the CPS as a foundation, the FAA conducted a Part 23
Regulatory Review and held meetings with the public and industry to
gain input on revising part 23. These meetings confirmed strong public
and industry support for the CPS recommendations to revise part 23.
    In 2011, the FAA formed the Part 23 Reorganization ARC to consider
further the CPS recommendation to reorganize part 23 based on airplane
performance and complexity and to investigate the use of consensus
standards. The ARC recommendations,\4\ published in 2013, echo the CPS
recommendations.
---------------------------------------------------------------------------

    \4\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    On January 7, 2013, Congress passed the Federal Aviation
Modernization and Reform Act of 2012 \5\ (Public Law 112-95; 49 U.S.C.
40101 note) (FAMRA), which requires the Administrator, in consultation
with the aviation industry, to assess the aircraft certification and
approval process. Based on the ARC recommendations and in response to
FAMRA, the FAA began work on this proposed rulemaking on September 24,
2013. Subsequently, on November 27, 2013, Congress passed the Small
Airplane Revitalization Act of 2013 (Public Law 113-53, 49 U.S.C. 44704
note) (SARA), which requires the FAA to issue a final rule revising the
certification requirements for small airplanes by--
---------------------------------------------------------------------------

    \5\ http://www.gpo.gov/fdsys/pkg/CRPT-112hrpt381/pdf/CRPT-112hrpt381.pdf.
---------------------------------------------------------------------------

     Creating a regulatory regime that will improve safety and
decrease certification costs;
     Setting safety objectives that will spur innovation and
technology adoption;
     Replacing prescriptive rules with performance-based
regulations; and
     Using consensus standards to clarify how safety objectives
may be met by specific designs and technologies.
    The FAA believes that the performance-based-standards component of
this proposal complies with the FAMRA and the SARA because it would
improve safety, reduce regulatory compliance costs, and spur innovation
and the adoption of new technology. This proposal would replace the
weight-and propulsion-based prescriptive airworthiness standards in
part 23 with performance- and risk-based airworthiness standards for
airplanes with a maximum seating capacity of 19 passengers or less and
a maximum takeoff weight of 19,000 pounds or less. The proposed
standards would maintain the level of safety associated with the
current part 23, while also facilitating the adoption of new and
innovative technology in general aviation (GA) airplanes.

B. Summary of Major Provisions

    This proposal to revise part 23 has two principal components:
Establishing a performance-based regulatory regime and adding new
certification standards for loss of control (LOC) and icing. Where the
FAA proposes to establish new certification requirements, these
requirements would be adopted within the same performance-based
framework proposed for part 23 as a whole.

1. Performance Standards and Airplane Crashworthiness
    Airplane crashworthiness and occupant safety is an example of how
moving towards performance-based standards and providing greater
flexibility to industry would increase aviation safety. Although the
FAA has over the years incrementally amended part 23 to enhance
occupant safety, these amendments have focused on individual system
components, rather than the safety of the system as a whole. By
building greater flexibility into FAA regulations governing crash
testing, this proposal would allow the aviation industry to develop and
implement novel solutions.
2. Loss of Control
    One proposed revision to part 23 would improve general aviation
safety by creating additional certification standards to reduce LOC
accidents. Inadvertent stalls resulting in airplane LOC are the most
common cause of small airplane fatal accidents. These LOC accidents
frequently occur in the traffic pattern or at low altitudes, where the
airplane is too low for a pilot to recover control before impacting the
ground. The proposed revisions would require applicants to use new
design approaches and technologies to improve airplane stall
characteristics and pilot situational awareness to prevent such
accidents.
3. Icing Certification Standards
    Another proposed revision to part 23 would improve GA safety by
addressing severe icing conditions. In the 1990s, the FAA became aware
of the need to expand the icing conditions considered during the
certification of airplanes and turbine aircraft engines. In particular,
the FAA determined that revised icing certification standards should
include Supercooled Large Drops (SLD),\6\ mixed phase, and ice
crystals.
---------------------------------------------------------------------------

    \6\ SLD conditions include freezing drizzle and freezing rain,
which contain drops larger than those specified in appendix C to
part 25, and can accrete aft of wing leading edge ice protection
systems.
---------------------------------------------------------------------------

    This proposed rule would require manufacturers that choose to
certify an airplane for flight in SLD to demonstrate safe operations in
SLD conditions. For those manufacturers who choose instead to certify
an airplane with a prohibition against flight in SLD conditions, this
proposed rule would require a means for detecting SLD conditions and
showing the airplane can safely exit such conditions. Industry has
indicated that these requirements would not impose significant
additional cost burden on industry because many manufacturers already
have equipped recent airplanes with technology to meet the standards
for detecting and exiting SLD conditions in accordance with current FAA
guidance.

C. Cost and Benefits

    The goal of this proposal is to create a cost-effective approach to
certification that facilitates the adoption of new safety enhancing
technologies and allows for alternative means of compliance. The FAA
has analyzed the benefits and costs associated with this NPRM. If the
proposed rule saves only one human life, for example, by improving
stall characteristics and stall warnings, that alone would result in
benefits outweighing the costs. The following table shows these
results.

                                 Estimated Benefits and Costs From 2017 to 2036
                                                [2014 $ millions]
----------------------------------------------------------------------------------------------------------------
                                                      Costs      Safety benefits + cost savings = total benefits
----------------------------------------------------------------------------------------------------------------
Total..........................................            $3.9  $19.6 + $12.6 = $32.2.
Present value..................................             3.9  $6.2 + $5.8 = $12.0.
----------------------------------------------------------------------------------------------------------------

    Accordingly, the FAA has determined that the proposed rule would be
cost beneficial.

II. Authority for This Rulemaking

    The FAA's authority to issue rules on aviation safety is found in
Title 49 of the United States Code. Subtitle I, Section 106 describes
the authority of the FAA Administrator. Subtitle VII, Aviation
Programs, describes in more detail the scope of the agency's authority.
    This rulemaking is promulgated under the authority described in
Subtitle VII, Part A, Subpart III, Section 44701. Under that section,
the FAA is charged with promoting safe flight of civil airplanes in air
commerce by prescribing minimum standards required in the interest of
safety for the design and performance of airplanes. This regulation is
within the scope of that authority because it prescribes new
performance-based safety standards for the design of normal, utility,
acrobatic, and commuter category airplanes.
    Additionally, this rulemaking addresses the Congressional mandate
set forth in the Small Airplane Revitalization Act of 2013 (Public Law
113-53; 49 U.S.C. 44704 note) (SARA). Section 3 of SARA requires the
Administrator to issue a final rule to advance the safety and continued
development of small airplanes by reorganizing the certification
requirements for such airplanes under part 23 to streamline the
approval of safety advancements. SARA directs that the rule address
specific recommendations of the 2013 Part 23 Reorganization Aviation
Rulemaking Committee (ARC).

III. Background

    The range of airplanes certificated under part 23 is diverse in
terms of performance capability, number of passengers, design
complexity, technology, and intended use. Currently, each part 23
airplane's certification requirements are determined by reference to a
combination of factors, including weight, number of passengers, and
propulsion type. The resulting divisions (i.e., normal, utility,
acrobatic, and commuter categories) historically were appropriate
because there was a clear relationship between the propulsion and
weight of the airplane and its associated performance and complexity.
    Technological developments have altered the dynamics of that
relationship. For example, high-performance and complex airplanes now
exist within the weight range that historically was occupied by only
light and simple airplanes. The introduction of high-performance,
lightweight airplanes required subsequent amendments of part 23 to
include more stringent and demanding standards--often based on the part
25 requirements for larger transport category airplanes--to ensure an
adequate level of safety for airplanes under part 23. The unintended
result is that some of the more stringent and demanding standards for
high-performance airplanes now apply to the

certification of simple and low-performance airplanes.

A. Part 23 History

    Part 23 originated from performance-based requirements developed by
the Bureau of Air Commerce and the Civil Aeronautics Administration in
the 1930s. These regulations were contained in specific Civil Air
Regulations (CAR) for the certification of aircraft (i.e., CAR 3, 4,
and 4a). These requirements, along with various bulletins and related
documents, were subsequently revised and first published as 14 CFR part
23 in 1964 (29 FR 17955, December 18, 1964). Over the past five decades
and after numerous amendments, part 23 has evolved into a body of
highly complex and prescriptive requirements attempting to codify
specific design requirements, address specific problems encountered
during prior certification projects, and respond to specific
recommendations from the National Transportation Safety Board (NTSB).
    Although the intent of the prescriptive language contained in
current part 23 was to increase the level of safety, prevent confusion,
and clarify ambiguities, the current regulations have also restrained
manufacturers' ability to employ new designs and testing methodologies.
The FAA believes moving towards performance-based standards should
significantly reduce or eliminate barriers to innovation and facilitate
the introduction of new safety-enhancing technologies.
    In 2008, the FAA conducted a review of part 23 by initiating the
Part 23 CPS. Collaborating with industry, the team's challenge was to
determine the future of part 23, given today's current products and
anticipated future products. The team identified opportunities for
improvements by examining the entire life cycle of a part 23 airplane.
The CPS recommended reorganizing part 23 using criteria focused on
performance and design complexity. The CPS also recommended that the
FAA implement general airworthiness requirements, with the means of
compliance defined in industry consensus standards standards. In 2010,
following the publication of the Part 23 CPS, the FAA held a series of
public meetings to seek feedback concerning the findings and
recommendations. Overall, the feedback was supportive of and in some
cases augmented the CPS recommendations.
    One notable difference between the CPS findings and the public
feedback was the public's request that the FAA revise part 23
certification requirements for simple, entry-level airplanes. Over the
past two decades, part 23 standards have become more complex as
industry has generally shifted towards correspondingly complex, high-
performance airplanes. This transition has placed an increased burden
on applicants seeking to certificate smaller, simpler airplanes. Public
comments requested that the FAA focus on reducing the costs and time
burden associated with certificating small airplanes by restructuring
the requirements based on perceived risk. The safety risk for most
simple airplane designs is typically low.
    On August 15, 2011, the Administrator chartered the Part 23
Reorganization ARC to consider the following CPS recommendations--
     Recommendation 1.1.1--Reorganize part 23 based on airplane
performance and complexity, rather than the existing weight and
propulsion divisions; and
     Recommendation 1.1.2--Certification requirements for part
23 airplanes should be written on a broad, general, and progressive
level, segmented into tiers based on complexity and performance.
    The ARC's recommendations took into account the FAMRA, which
requires the Administrator, in consultation with the aviation industry,
to assess the aircraft certification and approval process. The purpose
of the ARC's assessment was to develop recommendations for streamlining
and reengineering the certification process to improve efficiency,
reduce costs, and ensure that the Administrator can conduct
certifications and approvals in a manner that supports and enables the
development of new products and technologies and the global
competitiveness of the United States aviation industry.\7\ FAMRA also
directs the Administrator to consider the recommendations from the Part
23 Certification Process Study.\8\
---------------------------------------------------------------------------

    \7\ Section 312(c)
    \8\ Section 312 (b)(6)
---------------------------------------------------------------------------

    ARC membership represented a broad range of of stakeholder
perspectives, including U.S. and international manufacturers, trade
associations, and foreign civil aviation authorities. The ARC was
supported by FAA subject matter experts from all affected lines of
business, from design and production certification to continued
airworthiness and alterations. The following table identifies ARC
participants:

------------------------------------------------------------------------

------------------------------------------------------------------------
                           U.S. Manufacturers
------------------------------------------------------------------------
Avidyne.....................  Bendix-King.........  Cessna.
Cirrus......................  Continental Motors..  Cub Crafters.
GAMI........................  Garmin..............  Hawker Beechcraft.
Honda.......................  Honeywell...........  Kestrel.
Lockheed Martin.............  Rockwell-Collins....  Quest.
Sensenich Propellers........  Tamarack Aero.......  TruTrak.
------------------------------------------------------------------------
                           U.S. Organizations
------------------------------------------------------------------------
Aircraft Electronics          Aircraft Owners and   ASTM.
 Association (AEA).            Pilots Association
                               (AOPA).
Experimental Aircraft         General Aviation      National Air Traffic
 Association (EAA).            Manufacturers         Controllers
                               Association (GAMA).   Association
                                                     (NATCA).
RTCA........................  SAE.................
------------------------------------------------------------------------
                       International Manufacturers
------------------------------------------------------------------------
Dassault Falcon.............  Diamond.............  Flight Design.
Rotax.......................  Socata..............
------------------------------------------------------------------------

                International Civil Aviation Authorities
------------------------------------------------------------------------
European Aviation Safety      Transport Canada      National Civil
 Agency (EASA).                Civil Aviation        Aviation Agency of
                               (TCCA).               Brazil (ANAC).
Civil Aviation                Civil Aviation
 Administration of China       Authority of New
 (CAAC).                       Zealand.
------------------------------------------------------------------------

    Each member or participant on the committee represented an
identified segment of the aviation community, with the authority to
speak for that segment. The ARC also invited subject matter experts to
support specialized working groups and subgroups, as necessary. These
working groups developed recommendations and briefed the ARC as a
whole. The ARC then collectively discussed and voted to accept or
reject the recommendations. All of the recommendations included in the
ARC's report had overwhelming majority agreement.
    The ARC noted the prevailing view within industry was that the only
way to reduce the program risk, or business risk, associated with the
certification of new airplane designs was to avoid novel design
approaches and testing methodologies. The certification of new and
innovative products today frequently requires the FAA's use of ELOS
findings, special conditions, and exemptions. These take time,
resulting in uncertainty and high project costs. The ARC emphasized
that although industry needs from the outset to develop new airplanes
designed to use new technology, current certification costs inhibit the
introduction of new technology. The ARC identified prescriptive
certification requirements as a major barrier to installing
safety[hyphen]enhancing modifications in the existing fleet and to
producing newer, safer airplanes.
    The ARC also examined the harmonization of certification
requirements among the FAA and foreign civil aviation authorities
(CAAs), and the potential for such harmonization to improve safety
while reducing costs. Adopting performance-based safety regulations
that facilitate international harmonization, coupled with
internationally accepted means of compliance, could result in both
significant cost savings and the enabling of safety-enhancing equipment
installations. The ARC recommended that internationally accepted means
of compliance should be reviewed and voluntarily accepted by the
appropriate aviation authorities, in accordance with a process
established by those authorities. Although each CAA would be capable of
rejecting all or part of any particular means of compliance, the intent
would be to have full civil authority participation in the creation of
the means of compliance to ease acceptance of the means of compliance.

B. New Safety Requirements

    The performance-based standards proposed in this NPRM are designed
to maintain the level of safety provided by current part 23
requirements. The current part 23 weight and propulsion divisions were
based on assumptions that do not reflect the diversity of performance
capabilities, design complexity, technology, intended use, and seating
capacity of today's new airplane designs, or the future airplane
designs that will become possible as technology continues to evolve.
The FAA would therefore replace the current divisions with
certification levels 1 thru 4, low performance, high performance, and
simple. Furthermore, this would replace the current divisions within
the individual sections with technical and operational capabilities
focused on the technical drivers (e.g., stall speed, Visual Flight
Rules (VFR) and Instrument Flight Rules (IFR) operations,
pressurization). These types of technical and operational criteria
would apply a more appropriate set of standards to each airplane, and
continue to accommodate the wide range of airplane designs within part
23.
    To begin, the FAA proposes to eliminate commuter, utility, and
acrobatic airplane categories from part 23, retaining only a normal
category for all new part 23 type certificated airplane design
approvals. The differences between normal, utility, and acrobatic
categories are currently very limited and primarily affect airframe
structure requirements. Proposed part 23 would continue to allow a
normal category airplane to be approved for aerobatics, provided the
airplane is certificated for the safety factors and defined limits of
aerobatic operations.
    In addition, the FAA proposes that airplanes approved for spins be
certificated to aerobatic standards. Under the current Sec.  23.3(b),
the utility category provides airplanes additional margin for the more
stringent inertial structural loads resulting from intended spins and
other maneuvers. An airplane designed with traditional handling
qualities and designed to allow spin training is more susceptible to
inadvertent departure from controlled flight. The FAA therefore
believes that maintaining the current utility category for spin and
limited aerobatic maneuver capable airplanes would negate the largest,
single safety gain expected from this rulemaking action--the
significant reduction in inadvertent stall-related departures from
controlled flight.
    Under this proposal, airplanes already certificated in the
commuter, utility, and acrobatic categories would continue to fall
within those categories. Each new airplane design, however, would be
subject to varying levels of analysis, based on the potential risk and
performance of the airplane's design. A more rigorous standard, such as
currently applied to commuter category airplanes, would apply to higher
risk and higher performance airplanes.
    The proposed requirements would also include new enhanced standards
for resistance to departure from controlled flight. Recognizing that
the largest number of fatal accidents for part 23 airplanes results
from LOC in flight, the FAA proposes to update certification standards
to address these risks. LOC happens when an airplane enters a flight
regime outside its normal flight envelope or performance capabilities
and develops into a stall or spin, an event that can surprise the
pilot. A pilot's lack of awareness of the state of the airplane in
flight and the airplane's low-speed handling characteristics are the
main causal factors of LOC accidents. Furthermore, stall and departure
accidents are generally fatal because an airplane is often too low to
the ground for the pilot to recover. Improving safety that reduces
stall and LOC accidents would save lives. The FAA is therefore
proposing new rules for stall characteristics and stall warnings that
would result in airplane designs more resistant to inadvertently
departing controlled flight.
    Another type of low-speed LOC accident that occurs in significant
numbers involves minimum control speed (VMC) in light twin-
engine airplanes. Virtually all twin-engine airplanes have a
VMC that allows directional control to be maintained after
one engine fails. This speed is usually above the stall speed of the
airplane. However, light twin-engine airplanes typically have limited
climb capability on one engine. In the accidents reviewed by the ARC
and FAA, often in these situations, pilots attempted to maintain a
climb or

maintain altitude, which slowed the airplane down, rather than looking
for the best landing site immediately, maintaining control the whole
way. If the airplane's speed drops below VMC, the pilot can
lose control. In tying the minimum control speed to the stall speed of
the airplane, pilots, rather than attempting to maintain climb and lose
directional control, would instead react appropriately with stall
training techniques, resulting in a controlled descent rather than a
loss of directional control. This requirement will be on new airplanes
and should add little or no cost because it can be designed in from the
start.
    The FAA also has identified a need for improved certification
standards related to operations in severe icing conditions. More
specifically, in the 1990's, the FAA became aware of the need to expand
the icing conditions considered during the certification of airplanes
and turbine aircraft engines, to increase flight safety during some
severe icing conditions. The 1994 accident in Roselawn, Indiana,
involving an Avions de Transport Regional ATR 72 series airplane in SLD
conditions, brought to public and governmental attention safety
concerns about the adequacy of the existing icing certification
standards.
    As a result of the 1994 accident, and consistent with related NTSB
recommendations, in 1997 the Administrator tasked the Aviation
Rulemaking Advisory Committee (ARAC) (62 FR 64621, December 8, 1997)
with defining SLD, mixed phase, and ice crystal icing environments, and
designing corresponding safety requirements for those conditions. In
June 2000, the ARAC's task was revised to address only transport
category airplanes. More recent events, such as an Air France Airbus
model A330-203 AF447 \9\ accident, in 2009, highlighted the negative
effects of ice crystals on airspeed indication systems and turbojet
engines.
---------------------------------------------------------------------------

    \9\ See www.regulations.gov (Docket #FAA-2015-1621), Air France
A330-203, Flight AF 447 Final Accident Report
---------------------------------------------------------------------------

    The FAA ultimately published amendments 25-140 (79 FR 65507,
November 4, 2014) and 33-34 (79 FR 65507, November 4, 2014), Airplane
and Engine Certification Requirements in Supercooled Large Drop, Mixed
Phase, and Ice Crystal Icing Conditions that expanded parts 25 and 33
icing requirements, but did not amend part 23 requirements. On February
19, 2010, the Administrator chartered a Part 23 Icing ARC to review and
recommend SLD, mixed phase, and ice crystal icing conditions
regulations and guidance for part 23. In February 2012, the Part 23
Icing ARC formally identified a need to improve the part 23 regulations
to ensure safe operation of airplanes and engines in SLD and ice
crystal conditions.\10\ In particular, the Part 23 Icing ARC
recommended adopting most of the part 25 icing rules, including the
requirement to show either that an airplane can safely fly in SLD
conditions, or that it can detect and safely exit SLD. The proposals in
this NPRM incorporate the recommendations of the Part 23 Icing ARC.
---------------------------------------------------------------------------

    \10\ See www.regulations.gov (Docket #FAA-2015-1621)
---------------------------------------------------------------------------

C. Benefits for the Existing Fleet

    The proposed revisions would benefit owners and modifiers of
existing part 23 airplanes, as well as airplane designers and
manufacturers. Both currently and under this proposal, airplanes may be
modified by: (1) An alteration to an individual airplane; (2) a
supplemental type certificate (STC) for multiple airplanes, or (3) an
amendment to an original type design via an amended type certificate
(TC). This proposal would streamline each of these methods for
modifying airplanes.
    The proposed change to Sec.  21.9 would facilitate FAA approval of
low-risk equipment produced for installation in type-certificated
airplanes, thereby streamlining the process for owners to upgrade
equipment on their individual airplanes. An example of how this change
would facilitate safety improvements is the installation of inexpensive
weather display systems in the cockpits of small airplanes. These
systems allow a pilot to view current weather conditions along the
planned flight route and at the destination airport, avoiding
unexpected or deteriorating weather conditions. Since these systems are
not required and because they represent low safety risk from failure,
the FAA believes streamlining its approval process to produce them for
use in existing airplanes could lower costs and increase availability
of these systems.
    The proposed changes in the rules would also streamline the process
for design approval holders applying for a type design change, or for a
third party modifier applying for an STC, to incorporate new and
improved equipment in a model or several models of airplanes. Since the
revised part 23 standards would be much less prescriptive, the
certification process for modifications would be simplified.
Certification of an amended TC or STC under the proposed part 23
standards would require fewer special conditions or exemptions,
lowering costs and causing fewer project delays.

D. Conforming Amendments and Other Minor Amendments

    References to part 23 appear throughout the FAA's current
regulations. Accordingly, the FAA proposes to amend the following parts
for consistency with the proposed revisions to part 23: Part 21, part
35, part 43, part 91, part 121, and part 135.
    The FAA also proposes to revise part 21 to simplify the approval
process for low-risk articles. Specifically, the FAA proposes amending
Sec.  21.9 to allow FAA-approved production of replacement and
modification articles using methods not listed in Sec.  21.9(a). This
proposed change is intended to reduce constraints on the use of non-
required, low risk articles, such as carbon monoxide detectors and
weather display systems.

E. Public Policy Implementation

    The intent of this NPRM is to reduce regulatory barriers by
establishing a system based on safety-focused performance requirements
and FAA acceptance--as a means of compliance--of consensus standards.
FAA-accepted consensus standards would add clarity to the certification
process and streamline FAA involvement in the development of means of
compliance. Additionally, adopting performance standards would
significantly reduce the complexity of part 23. Furthermore, the
introduction of airplane certification levels based on risk (i.e.,
number of passengers) and performance (i.e., speed) would advance the
FAA's effort to introduce risk-based decision-making and better align
with the FAA's safety continuum philosophy. Together, the FAA believes
these changes would allow the FAA to provide appropriate oversight
based on the safety continuum and would restore a simple and cost
effective certification process based on proven engineering practices.
1. Regulatory Planning and Review
    In accordance with applicable executive orders, the FAA has
determined that the proposed revisions to part 23 are the most cost-
beneficial way of achieving the agency's regulatory objectives. This is
because the proposal would relieve industry of a significant regulatory
burden while maintaining or improving the level of safety under the
regulations. In particular, Executive Order 12866, Regulatory Planning
and Review (58 FR 51735, October 4, 1993), and Executive Order 13563,
Improving

Regulation and Regulatory Review (76 FR 3821, January 21, 2011), direct
each Federal agency to propose or adopt a regulation only upon a
reasoned determination that the benefits of the intended regulation
justify its costs. This proposal is not an economically ``significant
regulatory action'' as defined in section 3(f) of Executive Order 12866
\11\ and it satisfies Executive Order 13563 by protecting public
health, welfare, safety, while promoting economic growth, innovation,
competitiveness, and job creation.
    Under the above-referenced executive orders, when an agency
determines that a regulation is the best available method of achieving
its regulatory objective, the agency must design the regulation or
regulations in the most cost-effective manner. In doing so, each agency
must consider incentives for innovation, consistency, predictability,
enforcement and compliance costs (to the government, regulated
entities, and the public), flexibility, distributive impacts, and
equity. Each agency must identify and assess alternative forms of
regulation and shall specify, to the extent feasible, performance
objectives, rather than specifying the behavior or manner of compliance
that regulated entities must adopt. This proposal meets these
requirements because it would implement performance objectives rather
than a prescriptive methodology, thereby reducing time and cost burdens
on industry and increasing opportunities for innovation.
    Executive Order 13610, Identifying and Reducing Regulatory Burdens
(77 FR 28469, May 10, 2012) reiterates the direction from Executive
Order 13563 in stating that our regulatory system must measure, and
seek to improve, the actual results of regulatory requirements. To
promote this goal, agencies are to engage in periodic review of
existing regulations, and are required to develop retrospective review
plans to examine existing regulations in order to determine whether any
such regulations should be modified, streamlined, expanded, or
repealed. The purpose of this requirement is to make the agency's
regulatory program more effective or less burdensome in achieving the
regulatory objectives. In response to Executive Orders13563 and 13610,
agencies have developed and made available for public comment
retrospective review plans. Both the Part 23 Reorganization ARC and
this Part 23 Rulemaking Project are on the Department of
Transportation's retrospective review plans.
2. Consensus Standards
    Section 3(c) of SARA requires the Administrator, when developing
regulations, to comply with the requirements of the National Technology
Transfer and Advancement Act of 1995 \12\ (Pub. L. 104-113; 15 U.S.C.
272 note) (NTTAA) and to use consensus standards to the extent
practicable while maintaining traditional methods for meeting part 23.
Section 12(d) of the NTTAA directs Federal agencies to use, either by
reference or by inclusion, voluntary consensus standards in lieu of
government-mandated standards, except where inconsistent with law or
otherwise impractical. The Office of Management and Budget (OMB)
Circular A-119,\13\ Federal Participation in the Development and Use of
Voluntary Consensus Standards and Conformity Assessment Activities,
provides guidance to Executive agencies in implementing the
requirements of the NTTAA.
---------------------------------------------------------------------------

    \12\ http://www.gpo.gov/fdsys/pkg/PLAW-104publ113/pdf/PLAW-104publ113.pdf.
    \13\ https://www.whitehouse.gov/omb/circulars_a119/.
---------------------------------------------------------------------------

    Accordingly, the FAA proposes to accept consensus standards as a
means of compliance with the proposed part 23 performance-based
regulations. The use of consensus standards would be one means of
compliance with the performance-based standards of the proposed part
23. Compliance with the current prescriptive provisions within current
part 23 would be yet another means of compliance available under this
proposal. Applicants would still have the option to propose their own
means of compliance as they do today. The process for reviewing new
means of compliance would not change substantially from the process in
place today.
    Although a consensus standard works in some cases, the Part 23
Reorganization ARC expressed concerns that a consensus standard could
be biased in favor of a few large manufacturers and thereby create an
unfair competitive advantage. OMB Circular A-119 also cautions
regulators to avoid such potential biases. The FAA notes that industry
groups associated with the Part 23 Reorganization ARC identified ASTM
International (ASTM) as the appropriate organization to initiate the
development of consensus standards, and that ASTM permits any
interested party to participate in the committees developing consensus
standards. The FAA expects other consensus standards bodies to allow
similar opportunities for interested parties to participate in their
standards-development work. In addition to consensus standards and the
current prescriptive design standards in part 23, any individual or
organization may develop its own proposed means of compliance that may
be submitted to the FAA for acceptance.
3. International Cooperation Efforts for Reorganizing Part 23
    Executive Order 13609, Promoting International Regulatory
Cooperation (77 FR 26413, May 4, 2012), promotes international
regulatory cooperation to meet shared challenges and reduce, eliminate,
or prevent unnecessary differences in regulatory requirements.
Consistent with this Order, the FAA's proposal would address
unnecessary differences in regulatory requirements between the United
States and its major trading partners. The U.S. GA industry has
repeatedly informed the FAA of the high costs to address differences
between the airworthiness requirements of the FAA and foreign CAAs. The
FAA believes this proposal has the potential to achieve long-term
harmonization at an unprecedented level, and should result in a
significant savings for both U.S. manufacturers exporting products
abroad and foreign manufacturers exporting products to the U.S. The FAA
requests comments regarding the potential cost savings.
    The work of the Part 23 Reorganization ARC forms the foundation of
the proposed changes to part 23. From the onset, the ARC was a
cooperative, international effort. Representatives from several foreign
CAAs \14\ and international members from almost every GA manufacturer
of airplanes and avionics participated in the Part 23 Reorganization
ARC. Several international light-sport aircraft manufacturers, who were
interested in certificating their products using part 23 airworthiness
standards, also participated. In addition to recommending changes to
part 23, the ARC developed proposals to help reduce certification costs
through more international standardization of certification processes
and reducing or eliminating redundant certification activities
associated with foreign certification.
---------------------------------------------------------------------------

    \14\ CAAs included participants from Brazil, Canada, China,
Europe, and New Zealand.
---------------------------------------------------------------------------

    After the ARC issued its report, the FAA, foreign CAAs, and
industry continued to work together to refine the ARC rule language
until the FAA began drafting the NPRM in December 2014. This included
formal meetings in July and November of 2014. EASA,

Transport Canada, other foreign authorities, and industry offered
significant contributions to these efforts.
    In addition, the CAAs from Europe, Canada, Brazil, China, and New
Zealand are working to produce rules similar to those contained in this
proposal. EASA, for example, published an Advance Notice of Proposed
Amendment (A-NPA) 2015-06 on March 27, 2015, which sets forth EASA's
concept for its proposed reorganization of CS-23, and on which the FAA
provided comments. Like the FAA's current proposal, EASA's A-NPA was
also based on the proposed ARC language with the goal of harmonization.
Both proposals would adopt performance-based standards that facilitate
the use of consensus standards as a means of compliance.

F. Means of Compliance

    This proposal would allow type certificate applicants to use FAA-
accepted means of compliance to streamline the certification process.
This proposal, however, is shaped by two concerns raised in the Part 23
Reorganization ARC. First, the rule needs to clearly state that any
applicant must use a means of compliance accepted by the Administrator
when showing compliance with part 23. The FAA emphasizes that any means
of compliance would require FAA review and acceptance by the
Administrator. Second, although a means of compliance developed by a
consensus standards body (i.e., ASTM, SAE, RTCA, etc.) may be
available, any individual or organization would also be able to submit
its own means of compliance documentation to the Administrator for
consideration and potential acceptance.
    The FAA anticipates that both individuals and organizations would
develop acceptable means of complying with the proposed performance
standards. The industry groups associated with the ARC discussed the
development of consensus-based standards and selected ASTM as the
appropriate organization to initiate the effort. A standards
organization such as ASTM could, for example, generate a series of
consensus-based standards for review, acceptance, and public notice of
acceptance by the FAA. The ASTM standards would be one way, but not the
only way, to demonstrate compliance with part 23.
    Using means of compliance documents to satisfy compliance with the
proposed performance-based rules would diminish the need for special
conditions, ELOS findings, and exemptions to address new technology
advancements. Once the Administrator accepted a means of compliance, it
could be used in future certification applications unless formally
rescinded. Incorporating the use of consensus standards as a means of
compliance with performance-based regulations would provide the FAA
with the agility to more rapidly accept new technology as it develops,
leverage industry experience and expectations to develop of new means
of compliance documents, and encourage the use of harmonized means of
compliance among the FAA, industry, and foreign CAAs. Although an
applicant would not be required to use previously accepted means of
compliance documents, doing so would streamline the certification
process by eliminating the need for the FAA to develop an issue paper
to address the certification of new technology. Proposed Advisory
Circular 23.10, Accepted Means of Compliance, would describe a process
for applicants to submit proposed means of compliance to the FAA for
acceptance by the Administrator.
    The Part 23 Reorganization ARC was also concerned that specialists
in the industry could argue for complex means of compliance when the
FAA would accept a simpler or more cost effective approach. To address
these concerns, the FAA would continue to allow applicants to propose
their own means of compliance when the larger industry standard may be
the appropriate level of safety for one but not all certification
levels, consistent with the guidance in OMB Circular A-119, which
reminds the regulator that the government is responsible to the public
for setting the appropriate level of safety and avoiding any unfair
competitive advantage. Additionally, the FAA proposes to continue to
allow the use of the prescriptive means of compliance currently
codified in part 23 as yet another alternative means of compliance with
proposed part 23. This would not apply, however, to the proposed new
requirements, such as Sec. Sec.  23.200, 23.215, and 23.230.

G. FAA Strategic Initiatives

    The FAA's Strategic Initiatives 2014-2018 communicates FAA goals
for addressing the challenges presented by the changing aviation
industry and how the FAA intends to make the U.S. aviation system safer
and smarter, and raise the bar on safety. Specifically, one strategic
initiative is for the FAA to embrace and implement risk-based decision
making approaches, which build on safety management principles to
address emerging safety risks using consistent, data-informed
approaches to make smarter, quicker system-level decisions. By
establishing performance-based regulations, coupled with industry
standards, this proposed rulemaking would provide a calibrated and
globally competitive regulatory structure. This new approach would
increase safety in general aviation by enabling and facilitating
innovation and the implementation of safety enhancing designs in newly
certificated products.
    This rulemaking effort also directly supports the FAA's Global
Leadership Initiative, by encouraging global harmonization and the
consistent use of regulations, standards, and practices for general
aviation airplanes.

IV. Discussion of Proposal

A. Reorganization of Airworthiness Standards Based on Risk and
Performance

    The FAA proposes replacing the current weight and propulsion-based
airplane certification divisions with airplane certification and
performance levels based on the number of potential passengers and the
performance of the airplane. The FAA believes this proposed regulatory
change would better accommodate the wide range of airplanes
certificated under part 23, thereby reducing certification risk, time,
and costs.
    Historically, turbine-powered airplanes were assumed to fly at or
above 18,000 feet (5,486 meters) and at high speeds, whereas piston
engine airplanes were assumed to fly below 18,000 feet (5,486 meters)
and at lower speeds. Today, with advancements in aviation technology,
these general design and performance assumptions may not be valid.
Furthermore, the current regulations do not account for airplanes
equipped with new technologies, such as electric propulsion systems,
which may have features that are entirely different from piston and
turbine engines. For these reasons, the FAA is proposing regulations
based on airplane performance and potential risk rather than on
assumptions about specific technologies. These proposed standards would
be appropriate to each specific airplane design.
    Certification of airplanes under part 23 would either be conducted
using airplane certification levels based on maximum passenger seating
configuration and airplane performance levels based on speed, or occur
as so-called ``simple airplanes'' that are low-speed airplanes with a
stalling speed (VSO) <= 45 Knots Calibrated Airspeed (KCAS)
approved only for VFR operations. The FAA proposes the following
airplane certification levels:

     Level 1--for airplanes with a maximum seating
configuration of 0 to 1 passengers, including simple airplanes.
     Level 2--for airplanes with a maximum seating
configuration of 2 to 6 passengers.
     Level 3--for airplanes with a maximum seating
configuration of 7 to 9 passengers.
     Level 4--for airplanes with a maximum seating
configuration of 10 to 19 passengers.

B. Introduction of Simple Airplanes

    The regulations contained in part 23 have gradually become more
focused on high-performance, turbine-powered airplanes, and this
emphasis has become a barrier to the efficient certification and
introduction to market of new entry-level, simple airplanes. The Part
23 Reorganization ARC specifically noted that current part 23 does not
have appropriate standards for the certification of entry-level
airplanes.
    The FAA proposes to define ``simple airplanes'' in Sec.  23.5 to
recognize the entry-level airplane. Simple airplanes would be limited
to airplane designs that allow transport of no more than one passenger
(in addition to the pilot), are limited to VFR operations, and have
both a low top speed and a low stall speed. These airplanes are similar
to EASA's Certification Specification--Very Light Aeroplanes (CS-VLA),
which are currently imported to the U.S. and certificated as special
class airplanes in accordance with 14 CFR 21.17(b). The proposed change
would allow these airplanes to be certified as normal category
airplanes under part 23.
    The FAA believes that permitting certification of simple airplanes
would allow more certified entry-level airplanes to enter the
marketplace. The FAA expects simple airplanes to be a more basic
sublevel within proposed certification level 1, but recognizes that
because of similarities between simple and non-simple airplanes within
certification level 1, creating this category may be unnecessary. For
this reason, the FAA is specifically asking for comments concerning the
utility of creating a separate, simple airplane sublevel.

C. Establishing Performance-Based Standards and the Use of Means of
Compliance

    The Part 23 Reorganization ARC was aware the Administrator has
accepted as evidence of compliance various manufacturers' internal
design standards in the past, and the ARC recommended expressly stating
that option in the proposal. Proposed Sec.  23.10, Accepted Means of
Compliance, would allow individual persons or companies to submit their
internal standards as means of compliance for consideration by the
Administrator. Proposed Sec.  23.10 would also require an applicant to
show the FAA how it would demonstrate compliance with this part using a
means of compliance, which may include consensus standards accepted by
the Administrator. It would further require an applicant requesting
acceptance of a means of compliance to provide the means of compliance
to the FAA in a form and manner specified by the Administrator. In
addition, proposed Sec.  23.10 specifically recognizes the use of
consensus standards as a means of compliance that could be acceptable
to the Administrator. If this information is proprietary in nature, it
would be afforded the same protections as are applied today in
certification applications submitted under 14 CFR part 21.
    The phrase ``means of compliance'' may have different connotations
depending on its context. Historically, the FAA has treated an
applicant's demonstration of compliance as a means of compliance.
Alternatively, as indicated by sec. 3(b)(4) of the SARA, consensus
standards may constitute a means of compliance that can address new and
novel designs and technologies. In other words, as suggested by the
SARA, an applicant would develop a design to satisfy a performance-
based standard, and the design is the means of complying with the
standard.
    Currently, an applicant for a type certificate must show the FAA
how it satisfies the applicable airworthiness standards. The applicant
submits the type design, test reports, and computations necessary to
show compliance. The applicant approaches the FAA and enters into
negotiations regarding what constitutes an adequate demonstration--
testing or analysis. The FAA anticipates that, under the proposed
framework, standards developed by consensus standards bodies would
provide a pre-existing means by which any applicant may demonstrate
compliance with the corresponding performance-based requirements. For
example, the proposed fuel system requirements would be broad enough to
certificate airplanes with electric propulsion systems in which
batteries and fuel cells are used as fuel. Airplanes incorporating
these systems cannot currently be certificated without applying for
special conditions or exemptions.
    Elements of this proposal are already in place today. Industry
standards bodies like RTCA, SAE, ASTM, and the European Organization
for Civil Aviation Equipment (EUROCAE) have already developed detailed
means of compliance documents that an applicant for a type certificate
may use to demonstrate compliance with our regulatory requirements in
14 CFR parts 23, 25, 27, and 29. For decades, the FAA has identified
these means of compliance documents as an acceptable means of complying
with our regulatory requirements. This proposal would build on and
expand this aspect of our regulations by also transitioning part 23
towards a regulatory framework based on performance standards.

D. Crashworthiness as an Illustration of the Benefits of Performance-
Based Regulations

    One area where the implications of a change from prescriptive to
performance-based requirements are most evident is in the demonstration
of crashworthiness. The current part 23 crashworthiness and occupant
safety requirements are based on seat and restraint technology used in
the 1980's. Currently, an applicant demonstrates crashworthiness by a
sled test. Under the proposed standards, an applicant would not
necessarily have to perform a sled test, but could instead employ a
different method accounting for many other factors, several of which
are described below. The FAA is imposing no new requirements, but
would, under this proposal, provide greater flexibility to adopt new
safety-testing methodologies and, ultimately, more advanced safety
technologies.
    The FAA proposes to allow greater flexibility with respect to the
testing and demonstration, similar to advancements made in the
automotive industry over the past 30 years. The proposed regulations
would facilitate evaluation of the entirety of a crashworthiness
system--namely, the interaction of all crashworthiness features--rather
than requiring an evaluation of discrete, individual parameters. A
system's ability to protect occupants can be better understood by
evaluating it as a complete system, and using that greater
understanding to develop and implement new technologies. Such an
evaluation could include analyses of important survivability factors
identified by the NTSB, including occupant restraints, survivable
volume, energy-absorbing seats, and seat retention. These proposed
crashworthiness standards would not necessarily prevent accidents, but
should improve survivability.
    The NTSB produced a series of reports in the 1980s that evaluated
over 21,000 GA airplane crashes between 1972 and 1981. The NTSB General

Aviation Crashworthiness Project \15\ evaluated airplane orientation,
impact magnitudes, and survival rates and factors to provide
information supporting changes in crashworthiness design standards for
GA seating and restraint systems. The NTSB reports also established
conditions approximating survivable accidents and identified factors
that would have the largest impact on safety. Amendment 23-36 (53 FR
30802, August 15, 1988) to part 23 referenced these reports for dynamic
seats but did not adopt a systems-evaluation approach.
---------------------------------------------------------------------------

    \15\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    The NTSB reports identified several factors that, working together
as a system, should result in a safer airplane. The assessment also
indicated, however, that shoulder harnesses offer the most immediate
individual improvement for safety. The FAA codified the shoulder
harnesses requirement in amendments 23-19 (42 FR 20601, June 16, 1977)
and 23-32 (50 FR 46872, November 13, 1985) for newly manufactured
airplanes. The FAA also issued policy statement ACE-00-23.561-01,
Methods of Approval of Retrofit Shoulder Harness Installations in Small
Airplanes,\16\ dated September 19, 2000, to streamline the process for
retrofitting older airplanes. Current part 23 requires occupant
restraints to maintain integrity, stay in place on the occupant
throughout an event, properly distribute loads on the occupant, and
restrain the occupant by mitigating interaction with other items in the
cabin. Newer technologies that enhance or supplement the performance of
these restraints, such as airbags, are now being considered for
inclusion in designs. The use of airbags has greatly increased
passenger safety in automobiles, by offering protection in much more
severe impacts and in impacts from multiple directions. The proposed
performance standards would enable the use of these technologies.
---------------------------------------------------------------------------

    \16\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    Survivable volume is another critical factor in crashworthiness.
Survivable volume is the ability of the airframe to protect the
occupants from external intrusion, or the airplane cabin crushing
during and after an accident. There were several observed accidents in
the NTSB study where conventional airplane construction simply crushed
an otherwise restrained occupant. Crashworthiness regulations have
never included survivable volume as a factor, except in some instances
in which an airplane turns over. Airplane designs should provide the
space needed for the protection and restraint of the occupants. This is
one of the first steps in the analysis of airplane crashworthiness.
    Data from the NTSB General Aviation Crashworthiness Project
suggested that energy-absorbing seats that protect the occupant from
vertical impact loads could enhance occupant survivability and prevent
serious injury, thereby enhancing odds for exiting the airplane and
preventing many debilitating long-term injuries. The FAA established
dynamic seat testing requirements in amendment 23-36 for airplanes
certificated under part 23. Energy absorbing seats have a smaller
impact than some other safety factors because accident impacts with
large vertical components tend to have lower odds of survival.
Nevertheless, energy attenuation from vertical forces, both static and
dynamic, has been important to crashworthiness regulations for the past
25 years. Seats may crush or collapse, but must remain attached to the
body of the airplane. Coupling the seat performance to the rest of the
airframe response is important to the enhancement and understanding of
occupant survivability. The FAA believes allowing designers to consider
airframe deformation would result in more accurate floor impulses,
which relate to simulated crash impact, and may allow for evaluation
for crash impulses in multiple directions.
    The NTSB also identified seat retention as another basic building
block for airplane crashworthiness. The NTSB reports show more than a
quarter of otherwise-survivable accidents included instances where the
seats broke free at the attachment to the airplane, resulting in
fatalities or serious injuries. Dynamic seat testing requirements
address the ability of seat assemblies to remain attached to the floor,
even when the floor shifts during impact. Pitching and yawing of the
seat tracks during dynamic seat tests demonstrates the gimbaling and
flexibility of the seat.
    The FAA believes that, under this proposal, all of these
crashworthiness factors could be incorporated into future testing
methodologies and thereby increase the survivability of accidents in
part 23 certificated airplanes. This proposed part 23 amendment would
authorize design approval applicants to use these technologies and
testing methodologies to enhance occupant safety.

E. Additional Requirements To Prevent LOC

    LOC continues to be the leading cause of fatal GA accidents. The
FAA identified 74 accidents caused by stall or LOC between January 2008
and December 2013. These accidents, which are listed in Appendix IV of
the Part 23 Regulatory Evaluation,\17\ represent the type of accidents
that could be prevented by the proposed new stall and LOC requirements.
---------------------------------------------------------------------------

    \17\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    The FAA proposes to add requirements in Sec. Sec.  23.200 and
23.215 to prevent LOC accidents. Inadvertent stalls resulting in
airplane LOC cause a large number of small airplane fatal accidents.
These LOC accidents in the traffic pattern or at low altitudes often
result in fatalities because the airplane is too low to the ground for
the pilot to recover control. The FAA therefore believes it can improve
safety by requiring applicants to use new approaches to improve
airplane stall characteristics to prevent such accidents.
    Another type of low-speed LOC accident that occurs in significant
numbers involves VMC in light twin-engine airplanes.
Virtually all twin-engine airplanes have a VMC that allows
directional control to be maintained after one engine fails. This speed
is typically above the stall speed of the airplane. However, light
twin-engine airplanes also typically have limited climb capability on
one engine. Moreover, after the failure of one engine, pilots often
instinctively tend to try to maintain a climb or maintain altitude,
which slows the airplane down. If the speed drops below VMC,
the pilot can lose control of the airplane. Because pilots tend to be
more aware of the airplane's stall speed, the FAA proposes in Sec.
23.200 that certification levels 1 and 2 multiengine airplanes would be
required to have a VMC that does not exceed the stall speed
of the airplane for each configuration. The FAA believes this proposed
requirement would provide a higher level of safety than current Sec.
23.149. The FAA requests comments on this proposal.
    The FAA also proposes new requirements in Sec.  23.215 for airplane
stall characteristics and stall warning that would result in airplane
designs more resistant to inadvertently stalling and departing
controlled flight. These proposed requirements would increase the level
of safety over the current requirements. At the same time, the FAA
proposes to eliminate the spin recovery requirement in the current
rules for normal category airplanes. The FAA believes the spin recovery
requirement is unnecessary for normal category airplanes because the
vast

majority of inadvertent stalls leading to spin entry occur below a safe
altitude for spin recovery. However, airplanes certificated for
aerobatics would still have to meet spin recovery requirements.
    The FAA also proposes to address pilot stall awareness by requiring
warnings that are more effective and by allowing new approaches to
improve pilot awareness of stall margins. These warnings could be as
simple as angle of attack or energy awareness presentations, or
sophisticated envelope protection systems that add a forward force to
the pilot's controls as the airplane speed and attitude approach stall.

F. Additional Requirements for Flight in Icing Conditions

    The FAA proposes to implement the Part 23 Icing ARC's
recommendations in Sec. Sec.  23.230, 23.940 and 23.1405, to allow an
applicant the option of certifying an airplane to operate in SLD icing
conditions. To do so, an applicant would be required to meet the same
safety standards in SLD icing conditions as currently demonstrated for
part 23 airplanes in the icing conditions defined in appendix C to part
25.
    Currently, the FAA does not certify part 23 airplanes to operate in
SLD icing conditions, also known as freezing drizzle and freezing rain.
Instead, current part 23 icing regulations require airplane
performance, flight characteristics, systems, and engine operation to
be demonstrated in the icing conditions defined in appendix C to part
25, which does not contain SLD icing conditions. In 2012, prior to the
Part 23 Reorganization ARC, the Part 23 Icing ARC recommended revising
part 23 to include SLD icing requirements in subparts B, E, and F
(Flight, Powerplant, and Equipment, respectively).
    If an applicant chooses not to certify an airplane in SLD icing
conditions, proposed Sec.  23.230 would require the applicant to
demonstrate that SLD icing conditions could be detected and safely
exited. A means of compliance for SLD detection and exit may be found
in FAA Advisory Circular 23.1419-2D, Certification of Part 23 Airplanes
for Flight in Icing Conditions.\18\ The service history of airplanes
certificated under part 23 and certified to the latest icing standards
has shown that AC 23.1419-2D provides an adequate level of safety for
detecting and safely exiting SLD icing conditions. Industry has
indicated that these requirements would not impose an additional burden
because many manufacturers have already equipped recent airplanes to
meet the standards for detecting and exiting SLD in accordance with
current FAA guidance. Proposed Sec.  23.230, along with proposed Sec.
23.940, Powerplant ice protection, and Sec.  23.1405, Flight in icing
conditions, and their respective means of compliance, address NTSB
safety recommendations A-96-54 and A-96-56. The following table
provides a summary of the proposed icing regulations.
---------------------------------------------------------------------------

    \18\ See www.regulations.gov (Docket # FAA-2015-1621).

                       Proposed Icing Regulations
------------------------------------------------------------------------
                                                     Airframe and system
                                                         protection,
                                                       performance and
                                                           flight
  Part 23 type certificate      Engine protection      characteristics
         limitations             (Sec.   23.940)     requirements (Sec.
                                                       Sec.   23.230,
                                                        23.1300, and
                                                          23.1405)
------------------------------------------------------------------------
Not certified for flight in   Safe in part 25, App  None, except pitot
 icing conditions.             C conditions,         heat required if
                               ground ice fog, and   airplane certified
                               falling/blowing       for flight in
                               snow.                 instrument
                                                     meteorological
                                                     conditions (IMC).
Certified for flight in       Safe in part 25, App  Safe in part 25, App
 icing conditions, but         C conditions,         C conditions. Can
 prohibited for flight in      ground ice fog, and   detect SLD and
 SLD.                          falling/blowing       safely exit.
                               snow.
Certified for flight in       Safe in part 25, App  Safe in part 25, App
 icing conditions and SLD.     C conditions,         C conditions and
                               ground ice fog, and   SLD.
                               falling/blowing
                               snow, and SLD.
------------------------------------------------------------------------

G. Production of Replacement and Modification Articles

    The Part 23 Reorganization ARC recommended simplifying
certification requirements for non-required systems and equipment, with
an emphasis on improvement in overall fleet safety from the prevailing
level. In the past, the FAA has not established different production
requirements for required and non-required equipment that may enhance
safety, or for articles whose improper operation or failure would not
cause a hazard. The current requirements for producing articles and
representing those articles as suitable for installation on type-
certificated products are well suited for articles manufactured in
accordance with a product's TC or STC, as well as for TSO and PMA
parts. However, they may unnecessarily constrain the production of non-
required, low risk articles.
    Current standards for the production approval of these articles can
create a barrier for their installation in the existing fleet of
aircraft. Examples of such articles include carbon monoxide detectors,
weather display systems, clocks, small hand-held fire extinguishers,
and flashlights. In many cases, these articles are ``off-the-shelf''
products. It is frequently difficult for a person to install these
articles on a type-certificated aircraft because the level of design
and production details necessary for these articles to meet the
provisions of current Sec.  21.9, as expected for more critical
articles, are frequently unavailable.
    The FAA is therefore proposing to revise Sec.  21.9, Replacement
and Modification Articles, to provide applicants with an alternative
method to obtain FAA approval to produce replacement and modification
articles. This proposed change would allow a production approval
applicant to submit production information for a specific article,
without requiring the producer of the article to obtain approval of the
article's design or approval of its quality system. The FAA intends to
use the flexibility provided by this proposal to streamline the
approval process for non-required safety enhancing equipment and other
articles that pose little or no risk to aircraft occupants and the
public. The FAA requests comments on this proposal, and particularly is
interested in comments regarding whether the proposed change would
safely facilitate retrofit of low risk articles and whether there are
alternative methods to address the perceived retrofit barrier.

V. Key Terms and Concepts Used in This Document

    The proposal includes a number of terms introduced into the
regulations for the first time. These terms may be used

to replace existing prescriptive requirements or may explain other
terms that have had longstanding use in the aircraft certification
process, but in context of this rulemaking proposal, the FAA wants to
specify its meaning. These terms are intended to set forth and clarify
the safety intent of the proposed rules. Although certain terms may
differ from those currently in use, these differences are not intended
to increase the regulatory burden on an applicant unless specifically
stated. The FAA's intent is that the proposed requirements
incorporating these new terms not change the intent, understanding, or
implementation of the original rule unless that requirement has been
specifically revised in the proposal, such as is the case for
requirements governing stall characteristics. To assist applicants in
understanding the intent of the proposal, these terms are discussed
below:
    Airplane Certification Level--A division used for the certification
of airplanes that is associated directly with the number of passengers
on the airplane. Airplane certification levels would be established to
implement the agency's concept of certificating airplanes using a
process that recognizes a safety continuum.
    Airplane Performance Level--Maximum airspeed divisions that are
intended, along with airplane certification levels, to replace current
weight and propulsion divisions used for the certification of
airplanes. Current propulsion-based divisions assume that piston engine
airplanes are slower than turbine-powered airplanes. Current weight-
based divisions assume that heavier airplanes are more complex and
would be more likely to be used in commercial passenger carriage than
lighter airplanes. These assumptions are no longer valid. Airplane
certification based on performance levels would apply regulatory
standards appropriate to airplane's performance and complexity.
    Departure Resistant--For the purposes of this NPRM, departure
resistant refers to stall characteristics that make it very difficult
for the airplane to depart controlled flight. Most fatal stall or spin
accidents start below 1000 feet above ground level and do not actually
spin, but start a yawing and rolling maneuver to enter the spin called
a post stall gyration. In these low-altitude accidents, the airplane
typically hits the ground before completing one turn. Therefore, the
important safety criterion is preventing the airplane from exhibiting
stall characteristics that could result in a departure from controlled
flight.
    Entry-Level Airplane--A two or four-place airplane typically used
for training, rental, and by flying clubs. Historically, most of these
airplanes have four cylinder engines with less than 200 horsepower.
These airplanes typically have fixed-gear and fixed-pitch propellers,
but may also have retractable landing gear and constant speed
propellers. Entry-level airplanes typically cannot be used to train
pilots to meet the requirements to operate a complex aircraft, as that
term is defined for airman certification purposes.
    Equivalent Level of Safety (ELOS) Finding--A finding made by the
accountable aircraft certification directorate when literal compliance
with a certification requirement cannot be shown and compensating
factors in the design can be shown to provide a level of safety
equivalent to that established by the applicable airworthiness
standard.
    Fuel--Any source used by the powerplant to generate its power.
    Hazard--Any existing or potential condition that can lead to
injury, illness or death; damage to or loss of a system, equipment, or
property; or damage to the environment. A hazard is a condition that is
a prerequisite to an accident or an incident. (Cf. Order VS 8000.367,
Appendix A)
    Issue Paper--A structured means for describing and tracking the
resolution of significant technical, regulatory, and administrative
issues that occur during a certification project. The issue paper
process constitutes a formal communication vehicle for addressing
significant issues among an applicant, the FAA, and if applicable, the
validating authority (VA) or certificating authority (CA) for type
validation programs. An issue paper may also be used to address novel
or controversial technical issues.
    Means of Compliance--A documented procedure used by an applicant to
demonstrate compliance to a performance or outcome-based standard.
Similar to an Advisory Circular (AC), a means of compliance is one
method, but not the only method, to show compliance with a regulatory
requirement. Additionally, if a procedure is used as a means of
compliance, it must be followed completely to maintain the integrity of
the means of compliance.
    Performance- or Outcome-Based Standard--A standard that states
requirements in terms of required results, but does not prescribe any
specific method for achieving the required results. A performance-based
standard may define the functional requirements for an item,
operational requirements, or interface and interchangeability
characteristics.
    Pilot or Flightcrew--This is used generically throughout the
proposed part 23 because part 23 has airplanes approved for single
pilot operations as well as and two flightcrew members. For most
airplanes certificated under part 23 that are single pilot, applicants
should consider pilot and flightcrew to be interchangeable.
    Prescriptive Design Standard--Specifies a particular design
requirement, such as materials to be used, how to perform a test, or
how an item is to be fabricated or constructed. (Cf. OMB Circular A-119
Section 5.f.)
    Safety Continuum--The concept that one level of safety is not
appropriate for all aviation activities. Accordingly, higher levels of
risk, with corresponding requirements for less rigorous safety
demonstrations for products, are accepted as aircraft are utilized for
more personal forms of transportation.
    Survivable Volume--The airplane cabin's ability to resist external
intrusion or structural collapse during and after impact. The ability
to resist is usually represented as a stiffer design around the cabin
(not unlike a racecar roll cage) that is generally stronger than the
surrounding structure. While the airframe may deform or disintegrate
and attenuate impact energy, the cabin of the airplane will still
maintain its integrity and protect the occupants restrained within.
During otherwise survivable accident scenarios, including rollover,
this structure should maintain its shape under static and dynamic
loading conditions.

VI. Discussion of the Proposed Regulatory Amendments

A. Part 23, Airworthiness Standards

1. Subpart A--General
a. General Discussion
    The FAA proposes eliminating the utility, acrobatic, and commuter
categories for future airplanes certificated under part 23. The FAA
also proposes to change from weight and propulsion divisions to
performance and risk divisions. This would address the wide range of
airplanes to be certificated under part 23 and enhance application of
the safety continuum approach. Appendix 1 of this preamble contains a
cross-reference table detailing how the current regulations are
addressed in the proposed part 23 regulations.

b. Specific Discussion of Changes
i. Proposed Sec.  23.1, Applicability and Definition
    Proposed Sec.  23.1 would prescribe airworthiness standards for the
issuance of type certificates, and changes to those certificates, for
airplanes in the normal category. Current Sec.  23.3, Airplane
categories, defines normal category as airplanes that have a seating
configuration, excluding pilot seats, of nine or less, a maximum
certificated takeoff weight of 12,500 pounds or less, and intended for
nonacrobatic operation. Proposed Sec.  23.1 would delete references to
utility, acrobatic, and commuter category airplanes, and paragraph (b)
would not include the current reference to procedural requirements for
showing compliance. The reference to procedural requirements for
showing compliance is redundant with the requirement in Sec.  21.21,
Issue of type certificate: Normal, utility, acrobatic, commuter, and
transport category aircraft; manned free balloons; special classes of
aircraft; aircraft engines; propellers, to show compliance. Proposed
Sec.  23.1 would also add three definitions specific to part 23: (1)
Continued safe flight and landing, (2) designated fire zone, and (3)
empty weight.
ii. Proposed Sec.  23.5, Certification of Normal Category Airplanes
    Proposed Sec.  23.5 would apply certification in the normal
category to airplanes with a passenger-seating configuration of 19 or
less and a maximum certificated takeoff weight of 19,000 pounds or
less. Proposed Sec.  23.5 would also establish certification levels
based on the passenger seating configuration and airplane performance
levels based on speed.
    The diversity of airplanes certificated under part 23 is large
relative to performance, numbers of passengers, complexity, technology,
and intended use. Airplane certification requirements under part 23 are
currently determined using a combination of weight, numbers of
passengers, and propulsion type. These divisions historically were
appropriate because there was a clear relationship between the
propulsion and weight of the airplane and its associated performance
and complexity. Recent technological developments have altered the
dynamics of this relationship. High-performance and complex airplanes
now exist within the weight range that was typical for light and simple
airplanes. Furthermore, current part 23 has evolved to meet the
additional regulatory requirements resulting from the introduction of
high-performance airplanes. This has resulted in the introduction of
more stringent and demanding requirements in the lower weight airplanes
such as the use of 14 CFR part 25 based requirements for simple,
single-engine turbine airplanes. The result is that some of the current
requirements have become more demanding for simple and low-performance
airplanes.
    The FAA proposes replacing the current part 23 weight and
propulsion divisions because they were based on assumptions that do not
always fit the large diversity of airplane performance, complexity,
technology, intended use, and seating capacity encompassed in today's
new airplane designs. Also, the current divisions may not be
appropriate to address unforeseen designs of the future. The commuter
category, originally intended for the certification of airplanes over
12,500 pounds and up to 19 passengers, is currently used for larger
business jets with less than ten passengers. The proposed certification
and performance level approach, while different from the current
divisions, would capture the safety intent of part 23 more
appropriately than the current propulsion and weight divisions.
    The FAA proposes replacing the current divisions with specific
technical and operational capabilities by addressing, for example,
stall speed, VFR/IFR operation, pressurization, etc., that represent
the actual technical drivers for current prescriptive requirements.
These types of design specific technical and operational criteria would
be more appropriate for a means of compliance document where a complete
range of airplane designs could be addressed. The FAA proposes that
high-speed, multiengine airplanes and multiengine airplanes over 12,500
pounds should continue meeting the equivalent commuter category
performance-based requirements. The proposed performance requirements
would be based on number of passengers (certification level) and
airplane performance (performance level); not weight or propulsion
type.
    The FAA proposes to eliminate commuter, utility, and acrobatic
airplane categories in part 23, retaining only normal category for all
new part 23 type certificated airplane design approvals. The FAA
believes this action would not affect the existing fleet of small
airplanes. For example, the commuter category was originally introduced
into part 23 to apply to a 10 to 19 passenger, multiengine airplane,
operated in scheduled service under 14 CFR parts 121 and 135. However,
new airplanes certified under part 23 can no longer be used in
scheduled service under part 121 because Sec.  121.157, Aircraft
certification and equipment requirements, paragraph (h), requires a
part 25 certification for newly type certificated airplanes. The
majority of airplanes recently certified in the commuter category are
multiengine business jets. Additionally, the certification category of
commuter can be confused with the same term in the operating rules
because the term is defined differently in the certification and
operation rules. The FAA recognizes that moving away from weight and
propulsion divisions would result in changes for the criteria used to
determine when to apply the existing commuter category certification
requirements using the numbers of passenger seats (excluding crewmember
seats), performance, and technical divisions proposed in this NPRM. The
FAA proposes the following airplane certification levels:

     Level 1--for airplanes with a maximum seating
configuration of 0 to 1 passengers.
     Level 2--for airplanes with a maximum seating
configuration of 2 to 6 passengers.
     Level 3--for airplanes with a maximum seating
configuration of 7 to 9 passengers.
     Level 4--for airplanes with a maximum seating
configuration of 10 to 19 passengers.

    The differences between normal, utility, and acrobatic categories
are currently very limited and primarily affect airframe structure
requirements. Proposed part 23 would still allow a normal category
airplane to be approved for aerobatics provided the airplane was
certified to address the factors affecting safety for the defined
limits for that kind of operation. Currently, the utility category
provides airplanes additional margin for the more stringent inertial
structural loads resulting from intended spins and the additional
maneuvers stated in the requirements of the utility category in Sec.
23.3(b). The FAA proposes that airplanes approved for spins be
certificated to aerobatic standards. An airplane designed with
traditional handling qualities and designed to allow spin training is
more susceptible to inadvertent departure from controlled flight. The
FAA believes that maintaining the current utility category for
airplanes approved for spins and limited aerobatic maneuvers would
negate the single largest safety gain expected from this rulemaking
action--the significant reduction in inadvertent stall-related
departures from controlled flight.
    Proposed Sec.  23.5(c) would categorize the performance level of an
airplane as low speed or high speed. The combination of certification
levels and performance levels is intended to

provide divisions that address the actual safety concern of occupant
numbers and performance, for example, future designs using novel
propulsion methods. The FAA proposes the following airplane performance
levels:

     Low speed--for airplanes with a design cruising speed
(VC) or maximum operating limit speed (VMO) <=
250 KCAS (or MMO <= 0.6).
     High speed--for airplanes with a VC or
VMO > 250 KCAS (or MMO > 0.6).

    Proposed Sec.  23.5(d) would identify a simple airplane as one with
a certification level 1, a VC or VMO <= 250 KCAS
(and MMO <= 0.6), and a VSO <= 45 KCAS, and
approved only for VFR operations. The FAA proposes a simple airplane as
equivalent to airplanes certificated under EASA's current CS-VLA. In
most cases, EASA's CS-VLA requirements are identical to the proposed
corresponding part 23 requirements and have been proposed in the
requirements for certification level 1 airplanes. The FAA considered
using the CS-VLA standards in combination with the proposed part 23
certification standards for all certification level 1, low-speed
airplanes. However, the FAA believes that there are several
requirements in CS-VLA that are not appropriate for all certification
level 1, low-speed airplanes, such as no requirement for a type
certified engine in CS-VLA. Therefore, the FAA proposes creating a
limited certification and performance level for simple airplanes.
Simple airplanes would be a subset of certification level 1, low-speed
airplanes and would have a VSO <= 45 KCAS and would only be
approved for VFR operations.
    In accordance with the FAA's objective to remove weight and
propulsion divisions from the rules and use performance and
certification divisions, the proposed requirements applicable to the
certification of simple airplanes would not completely conform to the
criteria EASA uses to certificate very light airplanes. The FAA
proposes that simple airplanes would constitute a subset of
certification level 1, low-speed airplanes that would be required to
have a low stall speed limit and a VFR limitation in order to maintain
a level of safety appropriate for these airplanes. The FAA believes
that creating the simple certification level would encourage
manufacturers of light-sport and experimental aircraft kits to pursue
type certificates for their airplane designs without encountering the
administrative, procedural or regulatory barriers existing in current
part 23, while allowing innovative technology in those designs.
    The FAA considered allowing airplanes that meet the consensus
standards applicable to the certification of special light-sport
aircraft to be included in proposed part 23. However, the FAA decided
that this would not be in the best interest of the GA community because
it could result in the elimination of the special light-sport aircraft
category. There are advantages in the certification of special light-
sport aircraft, such as self-certification, that would not be available
if the aircraft were type certificated under part 23. This proposal
would instead enable a simpler path to part 23 certification for
airplanes that meet the definition of a light-sport aircraft and wish
to pursue a type of certificate for business reasons.
    The FAA expects simple airplanes to be more basic than the proposed
certification level 1, low-speed airplanes. A simple airplane is a
certification level 1, low-speed airplane with a stall speed limit of
45 KCAS that would be limited to VFR operations. The FAA recognizes
that a simple airplane level would have characteristics very similar to
certification level 1, low-speed airplanes, and that creating this
category may be unnecessary. For this reason, the FAA is specifically
asking for comments concerning the value of creating a separate, simple
airplane level.
iii. Proposed Sec.  23.10, Accepted Means of Compliance
    Proposed Sec.  23.10 would require an applicant to show the FAA how
it would demonstrate compliance with this part using a means of
compliance, which may include consensus standards, accepted by the
Administrator. Proposed Sec.  23.10 would also require an applicant
requesting acceptance of a means of compliance to provide the means of
compliance to the FAA in a form and manner specified by the
Administrator.
    Proposed Sec.  23.10 would create flexibility for applicants in
developing means of compliance and also specifically identify consensus
standards as a means of compliance the Administratory may find
acceptable. The Part 23 Reorganization ARC proposed using consensus
standards for the detailed means of compliance to the fundamental
safety requirements in proposed part 23. As discussed in the
International Harmonization Efforts section of this NPRM, the intent of
this proposal is to create a regulatory architecture for part 23 that
is agile enough to keep up with innovation. Allowing the use of
consensus standards would accomplish this goal.
    The Part 23 Reorganization ARC recommended creating this proposed
section to identify specifically the means of compliance documents
developed by industry, users such as large flight schools, the
interested public, and the FAA, that an applicant could use in
developing a certification application. The ARC expressed two concerns
that led to the creation of the proposed requirement. First, applicants
need to use a means of compliance accepted by the Administrator when
showing compliance to part 23. Second, while a consensus standards body
(i.e., ASTM, SAE, RTCA, etc.) developed means of compliance document
may be available, individuals or organizations may also submit their
own means of compliance documentation to the Administrator for
consideration and potential acceptance. Additionally, the FAA wants to
ensure applicants understand that an applicant-developed means of
compliance document would require FAA review and acceptance by the
Administrator.
    The FAA anticipates that individuals or organizations would develop
acceptable means for complying with the proposed performance standards.
A standards organization such as ASTM, for example, could generate a
series of consensus-based standards for review, acceptance, and public
notice of acceptance by the FAA. The ASTM standards could be one way,
but not the only way, to demonstrate compliance with part 23. Other
consensus standard bodies such as RTCA and SAE are currently focused on
developing standards for aircraft components and appliances.
    The proposed airworthiness standards would allow airplanes to be
certificated at different airplane certification levels. For example,
software integrity levels appropriate for a certification level 1
airplane may not be appropriate for a certification level 4 airplane.
Additionally, the takeoff performance of an airplane might be evaluated
differently for an airplane intended to be certificated at different
airplane certification levels. An applicant seeking certification of a
certification level 1 airplane with a takeoff distance of 200 feet, for
example, would not need to establish the takeoff distance with the same
degree of accuracy as would an applicant seeking certification of a
certification level 4 high-speed airplane with a takeoff distance of
4,000 feet.
    By using means of compliance documents to show compliance with the
proposed performance-based rules, the need for special conditions, ELOS

findings, and exemptions to address new technology advancements would
diminish. Once the Administrator accepted a means of compliance, it may
be used for future applications for certification unless formally
rescinded. Allowing the use of consensus standards as a means of
compliance to performance-based regulations would provide the FAA with
the agility necessary to more rapidly accept new technology, leverage
industry expectations in the development of new means of compliance
documents, and provide for the use of harmonized means of compliance
among the FAA, industry, and foreign CAAs. While an applicant would not
be required to use previously accepted means of compliance documents,
their use would streamline the certification process by eliminating the
need to develop an issue paper to address the certification of new
technology. Proposed AC 23.10,\19\ Accepted Means of Compliance, would
provide guidance for applicants on the process applicants would follow
to submit proposed means of compliance to the FAA for consideration by
the Administrator.
---------------------------------------------------------------------------

    \19\ See www.regulations.gov (Docket # FAA-2015-1621).
---------------------------------------------------------------------------

    The Part 23 Reorganization ARC expressed concerns that a consensus
standard could be biased in favor of a few large manufacturers and
would create an unfair competitive advantage. The FAA notes that any
interested party may participate in the ASTM committees developing
consensus standards thereby, mitigating this concern. The FAA expects
that other consensus standards bodies would allow similar opportunities
for interested parties to participate in their standards development
work. Additionally, any individual or organization could develop its
own means of compliance and submit it to the FAA for acceptance by the
Administrator. The other risk identified by the Part 23 Reorganization
ARC was that specialists in the industry could argue for complex means
of compliance when the FAA would accept a simpler or more cost
effective approach. However, the FAA would continue to allow applicants
to propose their own means of compliance when the larger industry
standard may be the appropriate level of safety for one, but not all
certification levels. Lastly, the FAA intends to continue to allow the
use of the current prescriptive means of compliance contained in
current part 23 requirements as one obvious alternative to showing
compliance with proposed part 23. This would not apply to the proposed
sections that contain new requirements, such as Sec. Sec.  23.200,
23.215, and 23.230.
    The Part 23 Reorganization ARC also was aware the Administrator has
accepted various manufacturers' internal standards in the past and
recommended having that option stated in the proposal. Proposed Sec.
23.10 would allow applicants to submit their internal standards as
means of compliance for consideration by the Administrator.
iv. Removal of Subpart A Current Regulations
    The FAA proposes removing current Sec.  23.2, Special retroactive
requirements, from part 23 because the operational rules currently
address these requirements. The current retroactive rule is more
appropriate in the operating rules. The FAA proposes amending 14 CFR
part 91, as discussed later in the Discussion of the Proposed
Regulatory Amendments to ensure removing the current Sec.  23.2
requirement would not affect the existing fleet.
2. Subpart B--Flight
a. General Discussion
    The FAA proposes moving away from the current stall characteristics
and spin testing approach to address the largest cause of fatal
accidents in small airplanes. Proposed Sec.  23.215 in subpart B would
omit the one turn/three second spin requirement for normal category
airplanes, but it would increase the stall handling characteristics and
stall warning requirements so the airplane would be substantially more
resistant to stall-based departures than the current rules require.
    The FAA also proposes eliminating the utility, acrobatic, and
commuter categories in part 23. Accordingly, a new airplane would have
to be approved for aerobatic loads as the normal category, even if an
applicant only wanted to spin the airplane. Therefore, the FAA proposes
to restrict certification of new airplanes for dual use, which can be
done today using both the normal and utility categories. The FAA
believes that if the airplane can spin for spin training, then the
airplane can inadvertently stall and depart into a spin during normal
operations. One of the FAA's goals is to prevent inadvertent stalls, so
allowing airplanes that are commonly used as rental airplanes to spin
would defeat the goal. However, the FAA would consider accepting a
dual-purpose airplane if the airplane manufacturer provided a system
that could be changed mechanically or electronically from normal to
aerobatic as a maintenance function rather than controlled by the
pilot.
    The FAA proposes consolidating the performance requirements for
high-speed multiengine airplanes and multiengine airplanes that weigh
over 12,500 pounds. These airplanes are currently required to meet a
series of one-engine-inoperative climb gradients. These climb gradients
were based on part 25 requirements and intended for commuter category
airplanes used in scheduled air service under parts 135 and 121. New
airplanes certificated under part 23 are not eligible for operation in
scheduled service under part 121, diminishing the utility of the
commuter category for these airplanes.
    More recently, part 23 multiengine jets intended to be used under
parts 91 or 135 have been certificated in the commuter category, using
part 25 based climb gradient requirements. In the spirit of the
proposed rule change, the FAA has decided that the one-engine-
inoperative climb requirements would be independent of the number of
engines and some of the original requirements would be consolidated
into a single requirement that would require performance very close to
what is required today. This action intends to maintain the performance
capabilities expected in 14 CFR part 135 operations.
    The FAA proposes changes in the flight characteristics rules to
keep the safety intent of the existing requirements consistent with the
other proposed part 23 sections. The current part 23 requirements are
based on small airplanes, designed with reversible controls, which
include some accommodations for stability augmentation and autopilots.
The FAA believes the proposed language would capture the current
requirements for flight characteristics and allows for varying degrees
of automated flight control systems in the future.
    Finally, the FAA proposes adding a requirement to require
certification levels 1 and 2 multiengine airplanes, not capable of
climbing after a critical loss of thrust, to stall prior to reaching
the minimum directional control speed (VMC).
b. Specific Discussion of Changes
i. Proposed Sec.  23.100, Weight and Center of Gravity
    Proposed Sec.  23.100 would require an applicant to determine
weights and centers of gravity that provide limits for the safe
operation of the airplane. Additionally, it would require an applicant
to show compliance with each requirement of this subpart at each
combination of weight and center of

gravity within the airplane's range of loading conditions using
tolerances acceptable to the Administrator. Proposed Sec.  23.100 would
also require the condition of the airplane at the time of determining
its empty weight and center of gravity to be well defined and easily
repeatable.
    Proposed Sec.  23.100 would capture the safety intent of current
Sec. Sec.  23.21, Proof of compliance; 23.23, Load distribution limits;
23.25, Weight limits; 23.29, Empty weight and corresponding center of
gravity; and 23.31, Removable ballast. This proposed section would
ensure an applicant considers the important weight and balance
configurations that influence performance, stability, and control when
showing compliance with the flight requirements. The main safety
requirements of current Sec. Sec.  23.21-23.31 are located in current
Sec. Sec.  23.21 and 23.23. Current Sec.  23.21 allows for a range of
loading conditions shown by test or systematic investigation. The
proposed rule would still allow for this flexibility, including the
tolerances for flight test. Sections 23.25-23.31 provide definitions
and directions for determining weights and centers of gravity and
provides directions for informing the pilot. For these reasons, the
information in these sections is more appropriate as a means of
compliance.
ii. Proposed Sec.  23.105, Performance
    Proposed Sec.  23.105 would require an airplane to meet the
performance requirements of this subpart in various conditions based on
the airplane's certification and performance levels for which
certification is requested. Proposed Sec.  23.105 also would require an
applicant to develop the performance data required by this subpart for
various conditions, while also accounting for losses due to atmospheric
conditions, cooling needs, and other demands on power sources. Finally,
proposed Sec.  23.105 would require the procedures used for determining
takeoff and landing distances to be executed consistently by pilots of
average skill in atmospheric conditions expected to be encountered in
service.
    Proposed Sec.  23.105 would capture the safety intent of current
Sec.  23.45, Performance--General. The safety intent of Sec.  23.45(a)
is captured in proposed Sec.  23.105(a) and is essentially unchanged
from the current rule, except to incorporate the proposed certification
levels and speed divisions.
    Proposed Sec.  23.105(b) would capture the safety intent of Sec.
23.45(b) by retaining Sec.  23.45(b)(1) requirements and combining
Sec.  23.45(b)(2) and (b)(3) and allowing all airplanes to use the
cooling climb limits as their upper temperature. The level of safety
remains the same as the current part 23 because part 23 airplane pilots
only have the limitations identified in the airplane flight manual,
including engine temperature limits.
    Proposed Sec.  23.105(c) would also capture the safety intent of
Sec.  23.45(f). The safety intent of the current rule is to ensure an
average pilot can consistently get the same results as published in the
Airplane Flight Manual (AFM). The FAA believes this requirement would
ensure applicants either perform their performance tests in a
conservative manner or add margins and procedures to the AFM
performance section so an average pilot can achieve the same
performance.
    Proposed Sec.  23.105(d) would require performance data to account
for losses due to atmospheric conditions, cooling needs, and other
demands. The current rule specifies the position of cowl flaps or other
means for controlling the engine air supply. The proposed language
accounts for airplane performance, if affected by the cooling needs of
the propulsion system, which is the safety intent of Sec.  23.45, but
would omit the details because they are more appropriate as a means of
compliance.
    Proposed Sec.  23.105(d) would also capture the safety intent Sec.
23.45(d) and (e). The safety intent of the current rule is to ensure
the airplane performance accounts for minimum power available from the
propulsion system, considering atmospheric and cooling conditions and
accessories requiring power.
iii. Proposed Sec.  23.110, Stall Speed
    Proposed Sec.  23.110 would require an applicant to determine the
airplane stall speed or the minimum steady flight speed for each flight
configuration used in normal operations, accounting for the most
adverse conditions for each flight configuration, with power set at
idle or zero thrust.
    Proposed Sec.  23.110 would capture the safety intent of current
Sec.  23.49, Stalling speed. Stall speeds are necessary to define
operating and limiting speeds used to determine airplane performance.
They also provide a basis for determining kinetic energy in emergency
landing conditions. Therefore, determining stall speeds is required in
the configurations used in the operation of the airplane.
    The FAA proposes removing the 61-knot stall speed division for
single-engine airplanes from the rules because this speed has not been
a limitation since 1992 with the addition of the options for stall
speeds in excess of 61 knots in Sec.  23.562, Emergency landing dynamic
conditions. Therefore, the 61-knot stall speed is a technical division
rather than a limitation and would be more appropriate as a means of
compliance.
    The FAA is changing its approach to crashworthiness. Instead of
constraining the connection between stall speed and crashworthiness to
a single fixed speed, the FAA proposes allowing alternative approaches
to crashworthiness. The intent is to encourage incorporation of
innovations from other industries to provide more occupant protection
in the airframe. This approach would base occupant protection on the
actual stall speed rather than a single mandated stall speed.
iv. Proposed Sec.  23.115, Takeoff Performance
    Proposed Sec.  23.115 would require an applicant to determine
airplane takeoff performance, which includes the determination of
ground roll and initial climb distance to 50 feet, accounting for stall
speed safety margins, minimum control speeds; and climb gradients.
Proposed Sec.  23.115 would also require the takeoff performance
determination to include accelerate-stop, ground roll and initial climb
to 50 feet, and net takeoff flight path, after a sudden critical loss
of thrust for certification levels 1, 2, and 3 high-speed multiengine
airplanes, multiengine airplanes with a maximum takeoff weight greater
than 12,500 pounds, and certification level 4 multiengine airplanes.
    Proposed Sec.  23.115 would capture the safety intent of current
Sec. Sec.  23.51, Takeoff speeds; and 23.61, Takeoff flight path.
Takeoff distance information and the associated procedures for
achieving those distances are necessary for the safe operation of all
airplanes certified under part 23. Proposed Sec.  23.115 would require
applicants to determine, develop, and publish distance and procedure
data for the pilot to use. The effects of airplane weight, field
temperature and elevation, winds, runway gradient, and runway surface
also need to be available to the pilot because they affect airplane
performance. For proposed simple entry-level airplanes, conservative
analysis may supplement flight test while data for larger, higher
performance airplanes are expected to provide the level of precision
that is accepted today.
    Additionally, proposed Sec.  23.115 would require applicants to
determine critical thrust loss cases for multiengine airplanes. Today,
the loss of one engine on a two-engine airplane is the standard model.
The future possibilities for the functions of engines, if different
from

thrust, and how the engines are controlled, may determine critical
thrust loss. For example, a large number of engines along the leading
edge of a wing could function as a high-lift device as well as provide
thrust.
    Historically, limited propulsion options and the need for inherent
stability from reversible, mechanical control systems have restrained
airplane configurations. The FAA anticipates that new propulsion
systems and affordable electronic flight control systems will challenge
these traditional designs and need alternative means of compliance.
Speed multiples and factors used in current part 23 prescriptive
requirements are based on traditional airplane configurations. Part 23
mandates these details of design for compliance. The FAA believes
removing these details would provide applicants with the agility and
flexibility to address these new airplane configurations. The current
factors will still apply for traditional configurations, but proposed
performance-based requirements should allow rapid adoption of new means
of compliance for future airplane configurations.
    The FAA proposes removing airplane categories and weight and
propulsion certification divisions for multiengine jets over 6,000
pounds and replacing them with divisions based on risk and performance.
The commuter category, originally intended for the certification of
airplanes over 12,500 pounds and up to 19 passengers, is currently used
for larger business jets with less than ten passengers. The FAA
proposes that high-speed, multiengine and multiengine airplanes over
12,500 pounds should continue meeting the equivalent commuter category
performance-based requirements. The historical assumption applied to
jets was that they were fast, had high wing loadings, and used
significant runway distances for takeoff and landing. Therefore, all
jets were required to have guaranteed climb performance with one engine
inoperative. This requirement does not currently apply to single engine
jets. The proposed performance requirements would be based on number of
passengers (certification level) and airplane performance (performance
level), not weight or propulsion type. The proposed certification and
performance levels approach would not offer a one-to-one relationship
with the current requirements. A low-speed turbine-powered airplane may
be more appropriately addressed by regulations currently applicable to
piston-powered airplanes, while a piston-powered or a high-speed
electric airplane may be more appropriately addressed by regulations
currently used for the certification of turbine-powered airplanes. The
proposed certification and performance level approach, while different
from the current divisions, would capture the safety intent of part 23
more appropriately than the current propulsion and weight divisions.
v. Proposed Sec.  23.120, Climb Requirements
    Proposed Sec.  23.120 would require an applicant to demonstrate
various minimum climb performances out of ground effect, depending on
the airplane's certification level, engines, and performance
capability. This new provision would capture the safety intent of
current Sec. Sec.  23.65, Climb: All engines operating; 23.67, Climb:
One engine inoperative; and 23.77, Balked landing. Minimum climb
performance information is necessary so pilots can determine if they
have adequate clearance from obstacles beyond the end of the runway.
New engine technologies, especially electric, would allow for
alternative configurations that would invalidate many of the detailed
test configuration and power assumptions that are in the current
requirements.
    Part 23 currently has a large matrix for all the climb requirements
that includes category, weight, and number of engines, resulting in
over 20 different climb gradient requirements. This reflects the growth
in the variety of different airplane types that has occurred since the
certification regulations were first adopted in CAR 3. Because the FAA
proposes simplifying these divisions using certification levels and
airplane performance levels, it can eliminate required climb gradients
for three and four engines. The FAA proposes basing multiengine climb
gradients on critical loss for thrust and using the gradient for the
current twin-engine airplanes because it has resulted in a safe service
history. The FAA proposes replacing the term ``failure of the critical
engine'' (which addresses a twin engine airplane) with ``critical loss
of thrust'' for airplanes certificated under those provisions. The
reason for replacing this term is that with configurations utilizing
large numbers of engines, the failure modes may not follow the
traditional failure modes as with the loss of one engine on a two-
engine airplane. Furthermore, the FAA proposes retaining and
consolidating the climb gradients from current Sec.  23.67 because
these gradients are important minimum performance requirements for
maintaining the current level of safety.
    Proposed Sec.  23.120(a) would capture the safety intent of current
Sec.  23.65. It would retain the existing climb gradients and
atmospheric conditions required for pilot planning.
    Proposed Sec.  23.120(b) would capture the safety intent of current
Sec.  23.67, and consolidates the weight and propulsion divisions into
all engines operating, critical loss of thrust, and balked landing
groups. Furthermore, for high-speed airplanes, after a critical loss of
thrust, the FAA proposes reducing the number of required climb
conditions for certification to one gradient at 400 feet (122 meters)
above the takeoff surface. For the typical part 23 certified twin-
engine airplane, the required climb gradient at 400 feet (122 meters)
above the takeoff surface is generally the most challenging. Airplanes
that have the performance to meet this one requirement typically can
meet all the current requirements. For certification levels 3 and 4,
high-speed multiengine airplanes, the FAA proposes consolidating the
configurations currently prescribed for the second segment climb and a
discontinued approach. The climb gradient difference between these
segments is 0.1 percent and uses the takeoff flap configuration rather
than the approach flap configuration. Requiring only one climb gradient
at 400 feet (122 meters) above the takeoff surface with the landing
gear retracted and flaps in the approach position would maintain the
current level of safety while reducing the requirements by eliminating
initial, final, and discontinued approach climb tests. Because the
proposed requirements would reduce the amount of climb testing for
designs intended for use under part 91, applicants would also need to
provide the traditional operational performance data, as is currently
done, if the design is intended to be used for commercial operations
under part 135 operating rules.
    The FAA also proposes to normalize the initial climb height to 50
feet (15 meters) above the takeoff surface. The regulations for the
certification of commuter category airplanes essentially adopted many
of the part 25 climb requirements, including an initial climb height of
35 feet (11 meters) above the takeoff surface. When the commuter
category was adopted, the expectation was that these airplanes would be
used in part 121 service. This expectation allowed the FAA to accept
the part 25 assumption that takeoff distances would be factored; thus,
providing a safety margin to offset the lower initial climb height.
Part 23 requirements provide minimum safe operations for part 91, which
does not require factored takeoff

distances. Therefore, allowing a 35 foot (11 meters) height above the
takeoff surface is a lower safety margin than used for smaller