[Federal Register: August 17, 2009 (Volume 74, Number 157)]
[Proposed Rules]
[Page 41521-41556]
[DOCID:fr17au09-13]

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Part III

Department of Transportation

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Federal Aviation Administration

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14 CFR Parts 1 and 23

Certification of Turbojets; Proposed Rule

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 1 and 23

[Docket No. FAA-2009-0738; Notice No. 09-09]
RIN 2120-AJ22

Certification of Turbojets

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This action proposes to enhance safety by amending the
applicable standards for part 23 turbojet-powered airplanes--which are
commonly referred to as ``turbojets''--to reflect the current needs of
industry, accommodate future trends, address emerging technologies, and
provide for future airplane operations. This action is necessary to
eliminate the current workload of processing exemptions, special
conditions, and equivalent levels of safety findings necessary to
certificate light part 23 turbojets. The intended effect of the
proposed changes would: Standardize and simplify the certification of
part 23 turbojets; clarify areas of frequent non-standardization and
misinterpretation, particularly for electronic equipment and system
certification; and codify existing certification requirements in
special conditions for new turbojets that incorporate new technologies.

DATES: Send your comments on or before November 16, 2009.

ADDRESSES: You may send comments identified by Docket Number FAA-2009-
0738 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, 1200 New Jersey Avenue, SE., Room W12-
140, West Building Ground Floor, Washington, DC 20590-0001.
     Hand Delivery or Courier: Bring 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>.

For more information on the rulemaking process, see the SUPPLEMENTARY
INFORMATION section of this document.
    Privacy: We will post all comments we receive, without change, to
http://www.regulations.gov, including any personal information you
provide. Using the search function of our docket Web site, anyone can
find and read the electronic form of all comments received into any of
our dockets, including the name of the individual sending the comment
(or signing the comment for an association, business, labor union,
etc.). You may review DOT's complete Privacy Act Statement in the
Federal Register published on April 11, 2000 (65 FR 19477-78) or you
may visit http://DocketsInfo.dot.gov.
    Docket: To read background documents or comments received, go to
http://www.regulations.gov at any time and follow the online
instructions for accessing the docket. Or, go 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.

FOR FURTHER INFORMATION CONTACT: For technical questions concerning
this proposed rule, contact Pat Mullen, Regulations and Policy, ACE-
111, Federal Aviation Administration, 901 Locust St., Kansas City, MO
64106; telephone:<PHONE_NUMBER>; facsimile<PHONE_NUMBER>; e-mail:
<EMAIL_ADDRESS>For legal questions concerning this proposed rule,
contact Mary Ellen Loftus, ACE-7, Federal Aviation Administration, 901
Locust St., Kansas City, MO 64106; telephone:<PHONE_NUMBER>; e-mail:
<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. Included in this discussion is
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.

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 safety
standards for the design of normal, utility, acrobatic, and commuter
category airplanes.

Table of Contents

I. Background
    A. Historical Certification Requirements Overview
    B. Aviation Rulemaking Committee (ARC) Recommendations
    C. Proposed Regulatory Requirements Overview
II. Discussion of the Proposed Regulatory Requirements
III. Regulatory Notices and Analyses
IV. The Proposed Amendments

I. Background

A. Historical Certification Requirements Overview

    Title 14 Code of Federal Regulations (14 CFR) part 23 provides the
airworthiness standards for Normal, Utility, Acrobatic, and Commuter
Category Airplanes. The first application for the certification of a
turbojet airplane under part 23 occurred in the 1970s before many of
the current turbine requirements were added to part 23. Prior to this,
turbojet powered airplanes were certificated to the standards under
part 25. Part 25 provides the airworthiness standards for Transport
category airplanes. A turbojet is a jet engine that develops thrust
using a turbine compressor which is propelled by high speed exhaust
gases expelled as a jet. The FAA implemented many of the certification
requirements for early part 23 turbojets through special conditions
based on 14 CFR part 25 (pre-amendment 25-42, (43 FR 2320))
requirements. Almost all special conditions applied to turbojets were
for part 23, subpart B, Flight, and subpart G, Operating Limitations
and Information.
    Special conditions for part 23 certification increased performance
requirements for emerging turbojets similar to those covered by early
part 25 standards. The FAA established these special conditions to
ensure a minimum one-engine inoperative (OEI) performance level that
would be included in the airplane's limitations, thereby guaranteeing
single-engine climb performance. The level of safety provided by the
special conditions was purposely higher for the early turbojets than
for propeller-driven airplanes in the same weight band because the
manufacturers and the FAA wanted part 23 turbojets to be similar to
part 25

business jets. Special conditions also addressed the following safety
concerns: (1) The lack of turbine requirements in part 23, (2) the
sensitivity of turbine engines to altitude and temperature effects, and
(3) the high takeoff and landing speeds associated with turbojets that
typically required long takeoff and landing distances, as compared to
the performance of reciprocating, multiengine airplanes of that era.
    In the mid-1990s, the FAA hosted a meeting for flight test pilot
representatives from the Aircraft Certification Offices. The purpose of
that meeting was to discuss how emerging 600 to 1,200 pound thrust
engines were being developed and how the FAA would certificate future
turbojet programs. The participants considered the prospect for small
single- and multi-engine turbojets. At that time, the FAA assumed that
any new part 23 turbojet would have similar characteristics to any
existing small part 25 turbojet. However, using the preliminary design
estimates from several new turbojets, FAA flight test personnel
realized these assumptions were outdated. Therefore, the FAA needed to
reevaluate its certification standards for turbojets against existing
light-weight airplanes.
    The meeting participants did not want to discourage development of
small part 23 turbojets by applying significantly higher standards than
for an equivalent propeller airplane. Therefore, the participants
decided the best approach for future turbojet certification programs
was to apply the existing part 23 weight differentiator of 6,000 pounds
in establishing requirements.

B. Aviation Rulemaking Committee (ARC) Recommendations

    On February 3, 2003, we published a notice announcing the creation
of the part 125/135 Aviation Rulemaking Committee.\1\ Part 125
addresses the certification and operations of airplanes having a
seating capacity of 20 or more passengers or a maximum payload capacity
of 6,000 pounds or more. Part 135 addresses the operating requirements
for commuter and on-demand operations and rules governing persons on
board such aircraft. Since some part 23 airplanes operate under parts
125 or 135, the ARC provided recommendations to the FAA for safety
standards applicable for part 23 turbojet airplanes to reflect the
current industry, industry trends, emerging technologies and operations
under parts 125 and 135, and associated regulations. The ARC also
reviewed the existing part 23 certification requirements and the
accident history of light piston-powered, multiengine airplanes up
through small turbojets used privately and for business. In addition,
the ARC reviewed the special conditions applied to part 23 turbojets.
The ARC completed its work in 2005 and submitted its recommendations to
the FAA. Those documents may be reviewed in the docket for this
proposed rule. The ARC recommended modifying forty-one 14 CFR part 23
sections as a result of its review of these areas.
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    \1\ 68 FR 5488
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    As stated earlier, the FAA's intent is to codify standards
consistent with the level of safety currently required through special
conditions. We compared the special conditions applied to part 23
turbojets, as well as several additional proposed part 23 changes, with
the ARC's recommendations. With few exceptions, the ARC recommendations
validated the FAA's long-held approach to certification of part 23
turbojets.
    The ARC did not want to impose commuter category takeoff speeds for
turbojets above 6,000 pounds, nor did the ARC want to impose more
stringent requirements for one-engine inoperative (OEI) climb
performance than those established for similar-sized piston-powered and
turboprop multiengine airplanes. The FAA ultimately accepted thirty-
nine of the forty-one ARC recommendations and developed this proposed
rulemaking in accordance with them. The two recommendations we
disagreed with would have lowered the standards previously applied
through special conditions.

C. Proposed Regulatory Requirements Overview

    The FAA currently issues type certificates (TCs) to part 23
turbojets using extensive special conditions, exemptions, and
equivalent levels of safety (ELOS). Until recently, this practice of
using special conditions, exemptions, and ELOS did not represent a
significant workload because there were relatively few part 23 turbojet
programs. However, in the past five years, the number of new part 23
turbojet type certification programs has increased more than 100
percent over the program numbers of the past three decades. The need to
incorporate special conditions, exemptions, and ELOS into part 23 stems
from this rise in the number of new turbojet programs and the expected
growth in the number of future programs. Codifying special conditions
would standardize and clarify the requirements for manufacturers during
the design phase of turbojets. Doing so would prevent instances where
manufacturers design turbojets and later have to demonstrate compliance
with special conditions that may require redesign. Codifying special
conditions, exemptions, and ELOS would also eliminate the
manufacturers' and the FAA's workload associated with processing these
documents and could reduce potential delays to project schedules. Many
of the proposed changes in this notice would codify certification
requirements and practices currently accomplished through use of
special conditions, exemptions, and ELOS.
    We propose changes to part 1 definitions to clarify new
requirements proposed for part 23. In addition, we propose changes to
part 23 in the areas of:
     Airplane categories to allow commuter category
certification of multiengine turbojets;
     Flight requirements, including standards for performance,
stability, stalls, and other flight characteristics;
     Structure requirements, including standards for emergency
landing conditions and fatigue evaluation;
     Design and construction requirements, including standards
for flutter, takeoff warning system, brakes, personnel and cargo
accommodations, pressurization, and fire protection;
     Powerplant requirements, including standards for engines,
powerplant controls and accessories, and powerplant fire protection;
     Equipment requirements, including general equipment
standards and standards for instruments installation, electrical
systems and equipment, and oxygen systems; and
     Operating limitations and information, including standards
for airspeed limitations, kinds of operation, markings and placards,
and airplane flight manual and approved manual material.

II. Discussion of the Proposed Regulatory Amendments

1. Part 1: Definitions Clarifying Power and Engine Terms

    We propose to amend part 1 definitions for ``rated takeoff power,''
``rated takeoff thrust,'' ``turbine engine,'' ``turbojet engine,'' and
``turboprop engine.'' Defining engine-specific terms would clarify the
new requirements proposed for part 23. The need to define some of these
terms was also shown by the following communications between the FAA
and members of industry. These communications were based on the
existing part 1 definitions for ``rated takeoff power'' and ``rated
takeoff thrust'', which limit the use of these

power and thrust ratings to no more than five minutes for takeoff
operation.
    In 1990, the Airline Transport Association (ATA) sent a letter to
the FAA asking the FAA to allow 10-minute OEI takeoff approval. At some
airports (mostly foreign), the climb gradient capability needed to
clear distant obstacles after takeoff requires more time at takeoff
thrust than 5 minutes. Using only 5 minutes of takeoff thrust to clear
distant obstacles limits the maximum allowable airplane takeoff weight.
The availability of takeoff thrust or power for use up to 10 minutes,
granted by some foreign authorities, enabled some foreign operators to
dispatch at an increased gross weight over that allowed for U.S.
operators. U.S. operators asked for equal treatment in similar
circumstances. The FAA has approved these requests when they have been
properly substantiated. This policy would also apply to operators of
part 23 turbojet-powered airplanes in order to achieve a climb gradient
necessary to clear obstacles.

2. Expanding Commuter Category to Include Turbojets

    Currently, we limit commuter category airplane requirements to
propeller-driven, multiengine airplanes. The FAA has issued exemptions
to allow turbojets weighing more than 12,500 pounds to be certificated
under part 23. The proposal to change Sec.  23.3 would codify the
current FAA practice of certificating multiengine turbojets weighing up
to and including 19,000 pounds under part 23 in the commuter category.

3. Performance, Flight Characteristics, and Other Design Considerations

a. Performance
    We propose to extend the commuter category performance requirements
to multiengine turbojets weighing more than 6,000 pounds. This proposal
codifies requirements that we currently impose by special conditions
for these airplanes. Amendment 23-45 (58 FR 42136) requires all
turbine-powered airplanes weighing 6,000 pounds or less to meet many of
the same performance standards for reciprocating-powered airplanes
weighing more than 6,000 pounds. The FAA has determined that turbojets
should meet a higher level of safety than reciprocating-powered
airplanes in the same weight band. By requiring turbojets over 6,000
pounds to meet the higher commuter category certification requirements,
the FAA would remain consistent in establishing more stringent
requirements for turbojet airplanes than for reciprocating airplanes.
    The ARC recommended no changes to performance requirements in
Sec. Sec.  23.51, 23.53, 23.55, 23.57, 23.59 and 23.61. The ARC pointed
out that applying the commuter category takeoff performance
requirements to multiengine turbojets weighing more than 6,000 pounds
would include restrictions that could become a takeoff weight
limitation for operations. The ARC stated that these requirements are
too restrictive for part 91 operations. However, existing multiengine
turbojets weighing more than 6,000 pounds are required to meet these
standards through special conditions, and we have seen negligible
operational impact. We have no rationale or basis to support a reduced
level of safety for part 23 turbojets.
    The ARC also reviewed FAA and Flight Safety Foundation accident
studies for engine failure on takeoff. The ARC determined that existing
normal category part 23 turboprops operated under part 135 have an
acceptable safety record when compared to turbojets. Furthermore,
turboprops in the accident studies were not certificated with any of
the commuter category performance requirements for climb gradients.
    The ARC believed the safety record of the turboprops had more to do
with the inherent reliability of turbine engines rather than the higher
climb gradient. An ARC member suggested the higher OEI climb gradients
originated in part 25 during the large piston transport airplane engine
era. Back then, the large piston engines were prone to failure on
takeoff or initial climb, and the requirements for OEI climb gradients
were necessary for safety.
    The ARC further believed raising the OEI climb performance
requirements for most multiengine airplanes was appropriate. However,
the ARC debated the appropriate OEI climb gradients for turbine-powered
airplanes over 6,000 pounds. Based on the reliability of turbine
engines, the ARC only recommended raising the climb performance to 1
percent. This matched the ARC's recommendation of 1 percent for
turbojets under 6,000 pounds. The ARC's recommendation, however, would
reduce the OEI climb performance that is currently required through
special conditions from 2 to 1 percent for turbojet-powered airplanes
over 6,000 pounds.
    Existing multiengine turbojets weighing more than 6,000 pounds are
required through special conditions to meet the commuter category
performance requirements (2 percent climb gradient) for OEI. We propose
to maintain the 2 percent OEI climb gradient currently applied through
special conditions for multiengine turbojets over 6,000 pounds. This
climb gradient requirement is safe and prudent, and it is not
reasonable to reduce the level of safety that already exists with part
23 turbojets.
    Although special conditions have required 2 percent OEI climb
gradient for multiengine turbojets over 6,000 pounds, there was no data
to support whether small turbojets under 6,000 pounds could meet the
higher 2 percent climb gradient while maintaining reasonable utility.
If our rule changes to Sec. Sec.  23.63 and 23.67 negatively impacted
their utility (i.e., weight-carrying ability), the rule might give the
piston-powered, multiengine airplanes a distinct market advantage.
Accident studies show that turbojets are generally safer than piston-
powered airplanes. Therefore, we wanted to compromise by proposing a
requirement that would provide an adequate minimum safety standard and
encourage production of more turbojets. One multiengine turbojet in
this weight band has been operated as an air taxi, and the FAA expects
this type of operation to grow. While this particular jet is capable of
higher climb performance, we propose only to increase the OEI climb
performance requirement to 1.2 percent because other jets in this
weight band may not be capable of the higher 2 percent climb
performance. Based on accident data, 1.2 percent provides an adequate
minimum safety standard.
    Historically, piston-powered, multiengine airplanes were allowed a
lower climb requirement because they would not have any weight-carrying
utility if forced to meet the same requirements of the larger
airplanes. We are continuing this philosophy in this proposal. (See
summary in the table below.)

             Table 1--One-Engine Inoperative Climb Requirements to 400 Feet Above Ground Level (AGL)
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                                                                                ARC
  Multiengine type/airplane weight band               Current rule             recommendation     FAA proposal
                                                                                (percent)         (percent)
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Pistons >6,000 lbs.......................  Measurably positive..............               1.0               1.0
Turboprops <=6,000 lbs...................  Measurably positive..............               1.0               1.0
Turboprops >6,000 lbs....................  Measurably positive..............               1.0               1.0
Turbojets <=6,000 lbs....................  Measurably positive..............               1.0               1.2
Turbojets >6,000 lbs.....................  2.0 percent imposed through                     1.0               2.0
                                            special conditions.
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    In addition to the proposed changes in takeoff and climb
performance requirements described above, we also propose changes to
other performance rules. Currently, part 23 reflects the traditional
small airplane definition of landing configuration stall speed
(VSO). However, certification personnel have interpreted
VSO in part 23 as being the same as that in part 25. This
interpretation has resulted in an unnecessary burden to the applicant.
We are revising the part 23 requirement so that it is distinct from the
part 25 requirement and to retain the original definition of the term.
We are proposing to revise paragraphs (a) and (c) of Sec.  23.49 to
clarify the section. We are also proposing to correct the title of this
section in the CFR to ``Stalling speed'' instead of ``Stalling
period.''
    VSO, by definition, is the stall speed in the maximum
landing flap configuration and is not applicable to other flap
configurations. (V speeds are defined in part 1. To simplify the
understanding of the proposed rule, we are adding this information
here.) Current Sec.  23.73 references VSO. The reference to
VSO in this paragraph is an error and should be changed to
reference the stall speed for a specified flap configuration
(VS1). The reference landing approach speed
(VREF) should be based on 1.3 times the VS1. We
propose to amend the standards to address airplanes certificated under
part 23 that may have more than one landing flap setting. We also
propose to apply the commuter category requirements for VREF
to multiengine turbojets over 6,000 pounds maximum weight. In addition,
we propose to apply the commuter category requirements for balked
landings in Sec.  23.77 to all multiengine turbine-powered airplanes
over 6,000 pounds, consistent with current special conditions for
multiengine turbojets and turbine-powered airplanes over 6,000 pounds.
b. Flight Characteristics
    The FAA proposes to define ``maximum allowable speed'' and to
clarify the specific speed limitations, which include specific criteria
for VFC, VLE, or VFC/MFC as
appropriate. The proposal for Sec.  23.177 would codify special
conditions that include specific speed limitations. Furthermore, we are
adding a new paragraph to Sec.  23.175(b) to define the VFC/
MFC (maximum speed for stability characteristics) term in
part 23. This definition was inadvertently omitted in the last revision
to part 23.
    The FAA proposes to amend the combined lateral-directional dynamic
stability damping requirements for airplanes that operate above 18,000
feet. The existing stability damping requirements, which apply at all
certificated altitudes, were developed when small airplanes typically
operated under 18,000 feet and were not equipped with yaw dampers. The
existing requirement remains appropriate for low altitude operations,
such as for approaches, but it is not appropriate for larger airplanes
that typically use yaw dampers and fly at altitudes well above 18,000
feet. The FAA has issued exemptions for most turbojets certificated
under part 23 because it is appropriate for high-altitude, high-speed
operations. The proposed changes to Sec.  23.181 would reduce the
stability damping requirement at 18,000 feet and above. If adopted,
this amendment would reduce the number of exemptions processed by the
FAA by codifying what is allowed as an acceptable means of compliance.
    The FAA proposes to amend the existing stall requirements in
Sec. Sec.  23.201 and 23.203 to include language from the turbojet
special conditions. We propose clarifying the requirements for wings-
level and accelerated turning stalls. We also propose changing the
roll-off requirements for wings-level, high-altitude stalls.
    The FAA proposes additional high-speed and high-altitude
requirements to Sec. Sec.  23.251 and 23.253 to address the new
generation of high performance part 23 airplanes. The FAA also proposes
to extend provisions from part 25, Sec. Sec.  25.251(d) and (e), to
part 23. However, we would limit the requirements to airplanes that fly
over 25,000 feet and have a Mach dive speed (MD) faster than
Mach 0.6 (M 0.6) to be consistent with part 25 requirements. The FAA
also proposes the use of VDF/MDF, which is
demonstrated flight dive speed (VDF) or Mach
(MDF) as referenced in the part 23 turbojet special
conditions.
    Furthermore, we propose adding requirements in a new Sec.  23.255
that would be based on Sec.  25.255 and would address potential high-
speed Mach effects for airplanes with MD greater than M 0.6.
The FAA's approach would only apply the part 25-based requirements to
airplanes that incorporate a trimmable horizontal stabilizer, which is
consistent with the ARC's recommendation. The ARC's recommendation was
based on the positive service history with the existing fleet of part
23 and part 25 turbojets designed with conventional horizontal tails
that use trimmable elevators. The industry manufacturers have designed
airplanes that have experienced upset incidents involving out-of-trim
conditions with a trimmable horizontal stabilizer. Service experience
shows that out-of-trim conditions can occur in flight for various
reasons, and the control and maneuvering characteristics of the
airplane may be critical in recovering from upsets. The proposed
language would require exploring the airplane's high-speed control and
maneuvering characteristics.
c. Other Design Considerations
    We propose to revise language in Sec.  23.703 in the introductory
text and paragraph (b) to add takeoff warning system requirements to
all airplanes over 6,000 pounds and all turbojets. The definition of an
unsafe condition, in this case, is the inability to rotate or prevent
an immediate stall after rotation. High temporary control forces that
can be quickly ``trimmed out'' would not necessarily be considered
unsafe.
    We have proposed the commuter category, rejected takeoff
requirements for all multiengine turbojets over 6,000 pounds. The
higher takeoff speeds and distances for these airplanes make the
ability to stop in a specified distance a safety issue. Additional
braking considerations accompany the rejected

takeoff requirements. Therefore, we propose to apply the requirements
for brakes in Sec.  23.735 to all multiengine turbojets over 6,000
pounds, as well as to all commuter category airplanes.

4. Structural Considerations for Crashworthiness and High-Altitude
Operations

    The FAA proposes to codify into Sec.  23.561 the recent turbojet
special conditions that were not available during the ARC's effort.
This proposal applies to single-engine turbojets with centerline
engines embedded in the fuselage. Part 23 did not encompass embedded
centerline engine installations, except for in-line propeller-pusher
types. In light of several new turbojet designs, it is prudent to
require greater engine retention strength for engines mounted aft of
the cabin. This is especially true for engines mounted inside the
fuselage behind the passengers. The proposed requirement would reduce
the potential for the engine to separate from its mounts under forward-
acting crash loads and subsequently intrude into the cabin. We recently
applied this proposed requirement to a single-engine turbojet through
special conditions.
    The ARC did not consider emergency landing dynamic conditions in
Sec.  23.562. We recognize, however, that Sec.  23.562 should be
applicable to all turbojets, including those operating in the commuter
category. All manufacturers of recently certificated commuter category
turbojets have agreed to comply with Sec.  23.562. The FAA proposes to
amend Sec.  23.562 to include all commuter category turbojets. This
proposal would adopt current industry practice and ensure a consistent
level of safety for all turbojets.
    At one time, the FAA proposed to apply the requirements for
emergency landing dynamic conditions to all commuter category
airplanes.\2\ Subsequently, we published new certification and
operations requirements for commuter operations.\3\ These actions
required certain commuter operators that previously conducted
operations under part 135 to conduct those operations under part 121.
This rule, in effect, eliminated the use of new part 23 airplanes with
10 seats or more in scheduled service. This action negated any
projected benefits supporting the addition of emergency landing dynamic
conditions to commuter category airplanes.
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    \2\ 58 FR 38028.
    \3\ 60 FR 65832 and 61 FR 2608.
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    The commuter operators affected were those conducting scheduled
passenger-carrying operations in airplanes that have passenger-seating
configurations of 10 to 30 seats (excluding any crewmember seat) and
those conducting scheduled passenger-carrying operations in turbojet
airplanes regardless of seating configuration. The action increased
safety in scheduled passenger-carrying operations and clarified,
updated, and consolidated the certification and operations requirements
for persons who transport passengers or property by air for
compensation or hire.
    In terms of overall configuration, commuter category turbojets have
little resemblance to their propeller-driven counterparts. During an
emergency landing, most commuter category turbojets will have more
structure underneath the cabin floor available to absorb energy than
traditional propeller-driven airplanes. This capability, along with the
differences in the overall airplane configuration of turbojets, would
suggest the test conditions specified in the current rule should be
applicable to all turbojets. However, commuter category airplanes
cannot exceed a maximum takeoff weight of 19,000 pounds. With this
limitation, the amount of crushable, energy absorbing structure is
small when compared to most part 25 airplanes. For this reason, we
propose to require the dynamic test conditions specified in part 23
rather than those in Sec.  25.562.
    We also propose to modify the seating head injury criteria (HIC)
calculation in the proposed rule to be consistent with the HIC
definition in part 25. This proposal addresses the concern that the HIC
definition in part 23 would lead to a HIC calculation only for the
total time of the head impact, which would not necessarily maximize
HIC.
    In the event of a ditching, the proposed change in Sec.  23.807
would provide an alternative to meeting the current requirement for an
emergency exit, above the waterline, on both sides of the cabin for
multiengine airplanes. Proposed section 23.807 would allow the
placement of a water barrier in the doorway before the door would be
opened as a means to comply with the above waterline exit requirement.
This barrier would be used to slow the inflow of water. The FAA has
approved the use of this barrier as an alternative to the above
waterline exit for several airplanes by issuing an ELOS finding.
    Several new part 23 turbojet programs include approval for
operations at altitudes above 40,000 feet. Additionally, the FAA has
issued special conditions for operations up to 49,000 feet. We propose
rule changes for structures and the cabin environment to ensure
structural integrity of the airplane at higher altitudes. We also
propose rule changes to prevent exposure of the occupants to cabin
pressure altitudes that could cause them physiological injury or
prevent the flight crew from safely flying and landing the airplane.
    We propose to amend Sec.  23.831 to add new paragraphs (c) and (d),
which include standards appropriate for airplanes operating at high
altitudes beyond those included in part 23. The proposed changes are
intended to ensure flight deck and cabin environments do not result in
the crew's mental errors or physical exhaustion that would prevent the
crew from successfully completing assigned tasks for continued safe
flight and landing. An applicant may demonstrate compliance with
paragraph (d) of this requirement if the applicant can show that the
flight deck crew's performance is not degraded.
    The cabin environment must be conservatively specified such that no
occupant would incur any permanent physiological harm after
depressurization. The environmental and physiological performance
limits used for demonstrating compliance must originate from recognized
and cognizant authorities as accepted by the regulatory authority
reviewing the compliance finding.
    As part of the certification process, we would consider the entire
flight profile of the airplane during the depressurization event. The
profile would include cruise and transient conditions during descent,
approach, landing, and rollout to a stop on the runway. We would not
include taxiing as a compliance consideration because the airplane
would be on the ground and could be evacuated, or flight deck windows
and cabin doors could be opened for ventilation. The condition of the
airplane from the beginning of the event to the end of the landing roll
is accounted for when assessing the safe exit of an airplane.
    We chose the words ``* * * shall not adversely affect crew
performance * * *'' to mean the crew can be expected to reliably
perform either their published or trained duties, or both, to complete
a safe flight and landing. We have measured this in the past by a
person's ability to track and perform tasks. The event should not
result in expecting the crew to perform tasks beyond the procedures
defined by the manufacturer or required by existing regulations. We use
the phrase ``No occupant shall sustain permanent physiological harm''
to mean the occupants who may have required some

form of assistance, once treated, must be expected to return to their
normal activities.
    To show compliance to the proposed rule, the applicant should
consider what would happen to the airplane and systems during
depressurization. The applicant may also consider operational
provisions, which provide for or mitigate the resulting environmental
effects to airplane occupants. If the manufacturer provides an approved
procedure(s) for depressurization, the flight deck and cabin crew may
configure the airplane to moderate either temperature or humidity
extremes, or both, on the flight deck and in the cabin. This
configuration may include turning off non-critical electrical equipment
and opening the flight deck door, or opening the flight deck window(s).
    As with Sec.  23.831, we find it necessary to amend the standards
in Sec.  23.841 to prevent exposure of the occupants to cabin pressure
altitudes that could keep the flight crew from safely flying and
landing the airplane or cause permanent physiological injury to the
occupants. The intent of the proposed changes to Sec.  23.841 is to
provide airworthiness standards that allow subsonic, pressurized
turbojets to operate at their maximum achievable altitudes--the highest
altitude an applicant can choose to demonstrate the effects to several
occupant related items after decompression. The applicant must show
that: (1) The flight crew would remain alert and be able to fly the
airplane, (2) the cabin occupants would be protected from the effects
of hypoxia (i.e., deprivation of adequate oxygen supply), and (3) if
some occupants do not receive supplemental oxygen, they would be
protected against permanent physiological harm.
    Existing rules require the cabin pressure control system maintain
the cabin at an altitude of not more than 15,000 feet if any probable
failure or malfunction in the pressurization system occurs. Cabin
pressure control systems on part 23 airplanes frequently exhibit a
slight overshoot above 15,000 feet cabin altitude before stabilizing
below 15,000 feet. Existing technology for cabin pressure control
systems on part 23 airplanes cannot prevent this momentary overshoot,
which prevents strict compliance with the rule. We have granted ELOS
findings for this characteristic because physiological data shows the
brief duration of the overshoot would have no significant effect on an
airplane's occupants.
    Special conditions issued for part 23 turbojets are similar and,
for operating altitudes above 41,000 feet, equivalent to the
requirements in Sec.  25.841 adopted in Amendment 25-87 (61 FR 28684).
That amendment revised Sec.  25.841(a) to include requirements for
pressurized cabins that were previously covered only in special
conditions. The special conditions required consideration of specific
failures. The FAA incorporated reliability, probability, and damage
tolerance concepts addressing other failures and methods of analysis
into part 25 after the issuance of the special conditions. Sections
23.571, 23.573, and 23.574 address damage tolerance requirements. We
propose to require the use of these additional methods of analysis as
part of this rulemaking.
    This proposal also specifies a more performance-based criterion,
such that failures cannot adversely affect crew performance nor result
in permanent physiological harm to passengers.

    (Note: There is a different standard for the crew than the
passengers.)

    Part 23 requires a warning of an excessive cabin altitude at 10,000
feet. Those regulations do not adequately address airfield operation
above 10,000 feet. Rather than disable the cabin altitude warning to
prevent nuisance warnings, we have issued ELOS findings that allow the
warning altitude setting to be shifted above the maximum approved field
elevation, not to exceed 15,000 feet. We propose to revise Sec.  23.841
to incorporate language from existing ELOSs into the regulation.
    Currently, we address oxygen systems for airplanes operating above
41,000 feet using special conditions derived from part 25. A large
number of new turbojets and high-performance airplanes entering part 23
certification will operate at higher altitudes than previously
envisioned for part 23 airplanes. We are proposing revisions to
Sec. Sec.  23.1443, 23.1445, and 23.1447 to establish requirements for
oxygen systems. These new requirements would eliminate the need for
special conditions for airplanes operating above 40,000 feet.

5. General Fire Protection and Flammability Standards for Insulation
Materials

    When we initially introduced powerplant fire protection provisions
in part 23, we did not foresee turbojet engines embedded in the
fuselage, nor in pylons on the aft fuselage, for airplanes certificated
to part 23 standards. We propose to add fire protection requirements
for turbojets in Sec. Sec.  23.1193, 23.1195, 23.1197, 23.1199, and
23.1201. Part 23 has historically addressed fire protection through
prevention, identification, and containment. Manufacturers have
provided prevention through minimizing the potential for ignition of
flammable fluids and vapors. Also historically, pilots had been able to
see the engines and identify the fire or use the incorporated fire
detection systems, or both. The ability to see the engine provided for
the rapid detection of a fire, which led to a fire being rapidly
extinguished. However, engine(s) embedded in the fuselage or in pylons
on the aft fuselage do not allow the pilot to see a fire.
    Isolating designated fire zones, through flammable fluid shutoff
valves and firewalls, provides for containment of a fire. Containing
fires ensures that components of the engine control system function
effectively to permit a safe shutdown of the engine. We have only
required a demonstration of containment for 15 minutes. If a fire
occurs in a traditional part 23 airplane, the corrective action is to
land as soon as possible. For a small, simple airplane originally
envisioned by part 23, it is possible to descend the airplane to a
suitable landing site within 15 minutes. If the isolation means do not
extinguish the fire, the occupants can safely exit the airplane before
the fire breaches the firewall.
    Simple and traditional airplanes normally have the engine located
away from critical flight control systems and the primary structure.
This location has ensured that throughout the fire event, the pilot can
continue safe flight and control of the airplane and predict the
effects of a fire. Other design features of simple and traditional
airplanes (e.g., low stall speeds and short landing distances) ensure
that even if an off-field landing occurs, the potential for a
catastrophic outcome is minimized.
    Specifically for airplanes equipped with embedded engines, the
consequences of a fire in an engine embedded in the fuselage are more
varied, adverse, and difficult to predict than the engine fire for a
typical part 23 airplane. Engine(s) embedded in the fuselage offer
minimal opportunity to actually see a fire. The ability to extinguish
an engine fire becomes extremely critical due to this location. With
the engine(s) embedded in the fuselage, an engine fire could affect
both the airplane's fuselage and the empennage structure, which
includes the pitch and yaw controls. A sustained fire could result in
damage to this primary structure and loss of airplane control before a
pilot could make an emergency landing. For embedded engine
installations, we also propose requiring a two-shot fire-extinguishing
system because the metallic components

in the fire zone can become hot enough to reignite flammable fumes
after someone extinguishes the first fire.
    We propose to upgrade flammability standards for thermal and
acoustic insulation materials used in part 23 airplanes. The current
standards do not realistically address situations where thermal or
acoustic insulation materials may contribute to propagating a fire. The
changes we propose are based on the requirements in Sec.  25.856(a),
which were adopted following accidents involving part 25 airplanes,
such as the Swissair MD-11. We believe the proposed standards would
enhance safety by reducing the incidence and severity of cabin fires,
particularly those in inaccessible areas where thermal and acoustic
insulation materials are installed.
    The proposed standards include new flammability tests and criteria
that address flame propagation, which would apply to thermal/acoustic
insulation material installed in the fuselage of part 23 airplanes.
Certification tests would consist of samples of thermal/acoustic
insulation that would be exposed to a radiant heat source and a propane
burner flame for 15 seconds. The insulation must not propagate flame
more than 2 inches away from the burner. The flame time after removal
of the burner must not exceed 3 seconds on any specimen. (See proposed
Part II, Appendix F to part 23 for more details.)
    Current flammability requirements focus almost exclusively on
materials located in occupied compartments (Sec.  23.853) and cargo
compartments (Sec.  23.855). The potential for an in-flight fire is not
limited to those specific compartments. Thermal/acoustic insulation can
be installed throughout the fuselage in other areas, such as
electrical/electronic compartments or surrounding air ducts, where the
potential also exists for materials to spread fire. Proposed Sec.
23.856 accounts for insulation installed within a specific compartment
in areas the regulations might not otherwise cover. Proposed Sec.
23.856 would be applicable to all part 23 airplanes, regardless of size
or passenger capacity. Advisory material describing test sample
configurations to address design details (e.g., tapes and hook-and-loop
fasteners) is available in DOT/FAA/AR-00/12, Aircraft Materials Fire
Test Handbook, dated April 2000. A copy of the handbook has been placed
in the docket for this rulemaking.
    Insulation is usually constructed in what is commonly referred to
as a ``blanket.'' Insulation blankets typically consist of two things:
(1) A batting of a material generically referred to as fiberglass
(i.e., glass fiber or glass wool), and (2) a film covering to contain
the batting and to resist moisture penetration, usually metalized or
non-metalized polyethylene terephthalate (PET), or metalized polyvinyl
fluoride (PVF). Polyimide, a heat-resistant fiber used in insulation
and adhesive, is another film used on certain airplanes. Regardless of
the film type used, there are variations associated with its assembly
for manufacture that result in performance differences from a fire
safety standpoint. These variations include the density of the film,
the type and fineness of the scrim bonded to the film, and the adhesive
used to bond the scrim to the film. The scrim resembles a screen, and
the mesh can vary in fineness. The scrim is usually constructed of
either nylon or polyester and is bonded to the backside of the film to
add shape and strength to the surface area. The adhesive used to bond
the scrim to the film also varies. However, the type of adhesive used
is important because fire retardant is frequently concentrated in the
adhesive of the assembled sheet.

6. Powerplant and Operational Considerations

    Current Sec.  23.777 standardizes the height and location of
powerplant controls because pilots may become confused and use the
wrong controls on propeller-driven airplanes. This requirement,
however, does not include single-power levers (which are typical for
electronically-controlled engines). The FAA currently makes an ELOS
finding for each airplane program that includes a single-power lever.
We propose to revise paragraph (d) in Sec.  23.777 to incorporate the
ELOS language.
    We propose to revise Sec.  23.903, paragraph (b)(2), to add
requirements for fuselage-embedded, turbofan engine installations.
These types of engine installations may have a negative impact on
passenger safety because passengers occupy an area directly ahead of
the turbojet engine fan disk. Certain turbofan engine designs have
failure conditions that allow the fan disk to exit the front of the
engine. This failure condition occurs if engines have bearing/shaft
configurations that would allow the disk to separate from the engine
and travel forward. If the engine has demonstrated this failure mode or
if an analysis shows such a failure is conceivable, then the
requirements of this section would apply. This requirement would be
applicable to engines embedded in the airplane's fuselage where it
could move forward into areas occupied by passengers or crew when a
disk fails.
    In addition to the changes described above, we also propose
requiring that electronic engine control systems meet the equipment,
systems, and installation standards of Sec.  23.1309. We have applied
this requirement to all digital engine controls in part 23 airplanes by
special condition. The proposed rule change for Sec.  23.1141 would
largely eliminate the need to issue special conditions on future
certification programs.
    The ARC believed few single-engine airplane manufacturers have
analyzed the criticality of their control system to meet the
requirements of this proposed rule. The fundamental rule change
recommended by the ARC for Sec.  23.1141 was not intended to invalidate
or overrule the 14 CFR part 33 certification requirements. The proposed
change for Sec.  23.1141 is intended for consideration of the airframe/
engine interface and how that interface protects against high intensity
radiated fields (HIRF) and lightning.
    Over the years, airplane engines, including turbines, generated
their own ignition system electrical power separate from the airplane's
electrical generation system. Even with a complete electrical failure
of the primary electrical systems, the engines would still run and be
fully functional. However, all new engines are not designed with self-
electrical-generation capability. Some new engines rely on the
airplane's electrical system to continue running and to be fully
functional. Revising Sec.  23.1165(f) would ensure that when approved
engines are installed on part 23 airframes, the engine ignition system
is identified as an essential load. This would ensure that those
engines have power during emergencies.\4\
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    \4\ Under the proposed changes, we would certificate new
engines, which include electronic ignition systems and engines with
electronic controls necessary for the engine's operation, through
the Engine and Propeller Directorate.
---------------------------------------------------------------------------

7. Avionics, Systems, and Equipment Changes

    Updated system requirements should reduce the regulatory burden on
the applicant by clarifying and expanding the applicability of
Sec. Sec.  23.1301 and 23.1309 to specific systems and functions. Most
new part 23 airplane manufacturers are installing electronic primary
flight displays (PFD) and multifunction displays (MFD) that replace
conventional electromechanical and mechanical instruments. These new
systems also offer more capability, reliability, and features that
improve safety.

    We propose changes that would address displays, software, hardware,
and power requirements. Besides advanced avionics and integrated
systems, we propose to update the certification requirements to
consider other advanced technologies (e.g., digital engine controls).
We intend to apply lessons learned from recent small turbojet
certification programs to update requirements for intended function and
system safety.
    The ARC did not make a specific recommendation for Sec.  23.1301.
However, the FAA seeks to clarify the intent of this section because it
is frequently misinterpreted and misapplied. Clarifying the intent of
Sec.  23.1301 would improve standardization for systems and equipment
certification, particularly for non-required equipment and non-
essential functions embedded within complex avionic systems. Our intent
is for the applicant to define proper functionality and to propose a
means of compliance acceptable to the Administrator. We expect
applicants to coordinate or negotiate deviations from established means
of compliance with the Administrator as early as possible to minimize
delay to project schedules.
    We propose to remove Sec.  23.1301(d), which currently states that
equipment must ``function properly when installed.'' The proposed
change would limit the scope of the rule since it would apply only to
equipment required for type certification or operation. We propose a
related change to clarify similar language in Sec.  23.1309 for proper
functionality of installed equipment.
    The ARC did not make a specific recommendation for Sec.  23.1303.
However, the FAA seeks to clarify the intent of this rule to
accommodate new technology and eliminate the need to issue an ELOS for
part 23 airplanes. We propose to amend Sec.  23.1303(c) by changing the
current requirement from ``A direction indicator (non-stabilized
magnetic compass)'' to ``A magnetic direction indicator.'' Section
23.1303 does not include a direction indicator, other than the typical
non-stabilized compass for part 23 airplanes. As new technology becomes
more affordable for part 23 airplanes, many electronic flight
instrument systems will use magnetically stabilized direction
indicators (or electric compass systems) to measure and indicate the
airplane heading to provide better performance.
    Current regulations require powerplant displays, referred to as
``indicators'' in Sec.  23.1305, to provide trend or rate-of-change
information. Advisory Circular (AC) 23.1311-1B, Installation of
Electronic Displays in Part 23 Airplanes, dated June 14, 2005,
currently provides a basis for an ELOS finding for digital engine
display parameters.\5\ The proposed rule changes to Sec. Sec.  23.1303,
23.1305, and 23.1311 would largely eliminate the need to issue ELOS
findings for these systems and help standardize certification of new
technology.
---------------------------------------------------------------------------

    \5\ A copy of the advisory circular is available on the Internet
at http://www.faa.gov/regulations_policies/.
---------------------------------------------------------------------------

    The ARC also did not make a specific recommendation for Sec.
23.1307. However, the FAA seeks to clarify language so applicants
understand they may need additional equipment to operate their
airplane. Part 23 is a minimum performance standard, and it may not
include all the required equipment for commercial operations under 14
CFR part 135. We propose to include parts 91 and 135 operations as
examples to use when deciding which equipment is necessary for an
airplane to operate at the maximum altitude.
a. System SafetyAssessment Requirements
    We originally designed the system safety assessment requirements of
Sec.  23.1309 to address certification of electronic systems driven by
microprocessors and other complex systems. However, the requirements of
Sec.  23.1309 are being applied to conventional mechanical and
electromechanical systems with well-established design and
certification processes. This was not our intent, and we propose to
revise Sec.  23.1309 to clarify the intended application of the rule.
    Proposed changes for Sec.  23.1309 also clarify the intent for
certification of electronic engine controls. The current section
excludes systems certificated with the engine. Therefore, we use
special conditions for all electronic engine control installation
approvals to capture the evaluation requirements of Sec.  23.1309. We
applied special conditions to the interface of the electronic engine
control system and the airplane. We also applied special conditions to
verify that the installation does not invalidate the assumptions made
during part 33 certification of the engine. This proposal would address
electronic engine controls and eliminate the need for special
conditions to apply Sec.  23.1309 to electronic engine control systems.
    Proposed Sec.  23.1309(a) would have requirements for two different
types of equipment and systems installed in the airplane. Proposed
Sec.  23.1309(a)(1) would cover the equipment and systems that have no
negative safety effect and those installed to meet a regulatory
requirement. Such systems and equipment are required to ``perform as
intended under the airplane operating and environmental conditions.''
Proposed Sec.  23.1309(a)(2) would require the applicant to show that
all equipment and systems (including approved ``amenities,'' such as a
coffee pot and entertainment systems) have no safety effect on the
operation of the airplane. The phrase ``improper functioning''
identifies equipment and system failures that have a potentially
negative effect on airplane safety. Therefore, we must consider their
potential failure condition(s). Using Sec.  23.1309, we must analyze
any installed equipment or system that has potential failure
condition(s) that are catastrophic, hazardous, major, or minor to
determine their impact on the safe operation of the airplane.
    We propose to clarify the certification requirements, environmental
qualification test requirements, and our intent for determining proper
``intended function'' of non-required systems and equipment that do not
have a safety effect on the airplane. A problem with the current
requirements for airplane manufacturers arises when certification
authorities question installation of non-required systems and equipment
that do not perform following their specifications and, therefore, are
``not functioning properly when installed.'' Usually, normal
installation practices can be based on a relatively simple qualitative
installation evaluation. If the possible safety impacts (including
failure modes or effects) are questionable, or isolation between
systems is provided by complex means, more formal structured evaluation
methods or a design change may be necessary. We do not require these
types of equipment and systems to function properly when installed.
However, we would require them to function when they are tested to
verify that they do not interfere with the operation of other airplane
equipment and systems and do not pose a hazard in and of themselves.
    Also under proposed changes to Sec.  23.1309(a), we would replace
the conditional qualifiers of ``under any foreseeable operating
condition,'' contained in the current Sec.  23.1309(b)(1), with ``under
the airplane operating and environmental conditions.'' Our intent with
this proposal is for the applicant to take two actions. First, the
applicant must consider the full normal operating envelope of the
airplane, as defined by the airplane flight manual (AFM), with any
modification to that envelope associated with abnormal or emergency
procedures and any anticipated crew

action. Second, the applicant must consider the anticipated external
and internal airplane environmental conditions, as well as any
additional conditions where equipment and systems are assumed to
``perform as intended.'' We propose to make this change in response to
an observation that although certain operating conditions are
foreseeable, achieving normal performance when they exist is not always
possible (e.g., you may foresee ash clouds from volcanic eruptions, but
airplanes with current technology cannot safely fly in such clouds).
    The FAA currently accepts equipment that is susceptible to failures
if these failures do not contribute significantly to the existing risks
(e.g., some degradation in functionality and capability is routinely
allowed during some environmental qualifications, such as HIRF and
lightning testing). System lightning protection specifically allows the
loss of function and capability of some electrical/electronic systems
when the airplane is exposed to lightning, if ``these functions can be
recovered in a timely manner.''
    Proposed Sec.  23.1309(a)(3) is applicable for all functional
reliability, flight testing, or flight evaluations. This proposed
change clarifies the FAA's expectations for functional testing during
certification of complex systems, but it is not meant to increase the
testing burden on the applicant. The FAA's intent is to prohibit
certification of systems with known defects in required functions that
could impact safety. For example, it would not be acceptable for an
integrated avionics system to be approved until known functional
defects in required functions are corrected. The system would not be
allowed to exhibit unintended or improper functionality for flight
critical functions. The rate of occurrence of failures, malfunctions,
and design errors must be appropriate for the failure condition(s) of
the type of system and airplane.
    Proposed Sec.  23.1309(b) would codify a long-established means of
compliance with current Sec.  23.1309(b) and update failure
condition(s) terminology used in related system safety assessment
documents developed by industry working groups (e.g., RTCA and the
Society of Automotive Engineers (SAE)). This means of compliance
identifies four classes of airplanes as defined in Appendix K of this
proposal and applies appropriate probability values and development
assurance levels for each class. The original text of Sec.
23.1309(b)(4) has been retained and appears as Sec.  23.1309(b)(5) in
this revision. The proposed changes to Sec.  23.1309(c) and (d) are
meant to define the proper scope and intent for applying Sec.  23.1309
depth of analysis for system safety assessments to all systems.
    With proposed Sec.  23.1309(f), we would make Sec.  23.1309
compatible with the current Sec.  23.1322 (``Warning, caution, and
advisory lights'') that distinguishes between caution, warning, and
advisory lights installed on the flight deck. Rather than only
providing a warning to the flight crew, which is required by the
current rule, proposed Sec.  23.1309(f) would require that information
concerning an unsafe system operating condition(s) be provided to the
flight crew.
    A warning indication would still be required if immediate action by
a flight crewmember were required. The particular method of indication
would depend on the urgency and need for flight crew awareness or
action that is necessary for the particular failure. Inherent airplane
characteristics may be used in lieu of dedicated indications and
annunciations that can be shown to be timely and effective. The use of
periodic maintenance or flight crew checks to detect significant latent
failures when they occur should not be used in lieu of practical and
reliable failure monitoring and indications.
    Proposed Sec.  23.1309(f) would clarify the current rule by
specifying that the design of systems and controls, including
indications and annunciations, must reduce crew errors that could
create more hazards. The additional hazards to be minimized would be
those that are caused by inappropriate actions made by a crewmember in
response to the failure, or those that could occur after a failure. Any
procedures for the flight crew to follow after the occurrence of a
failure indication or annunciation would be described in the approved
Airplane Flight Manual (AFM), AFM revision, or AFM supplement, unless
they are accepted as part of normal aviation abilities.
    Current Sec.  23.1309 (c) and (d) are not directly related to the
other safety and analysis requirements of Sec.  23.1309. The ARC
considered it appropriate to state the requirements separately for
clarity. We agree with this suggested change and propose to add a new
Sec.  23.1310 to accommodate the change. The requirements as originally
stated in current Sec.  23.1309 would not change, except for a new
section number.
    We propose several changes to Sec.  23.1311(a)(5) for plain
language purposes. In proposed Sec.  23.1311(a)(5), we replace the
phrase ``individual electronic display indicators'' with ``electronic
display parameters.'' The term ``indicator'' has a long-standing
definition based on conventional, mechanical indicators; therefore, the
term has caused confusion. These electronic display parameters could be
integrated on one electronic display that is independent of the primary
flight display. In proposed Sec.  23.1311(a)(6), we add the phrase
``that provide a quick-glance sense of rate and, when appropriate,
trend information'' to clarify ``sensory cues.''
    We propose to add the term ``when appropriate'' to eliminate the
requirement to display trend information when it would otherwise
provide intuitive information to the pilot. For example, the trend for
fuel burn is always negative. We propose to remove the remainder of
section (a)(6), ``* * * that are equivalent to those in the instrument
being replaced by the electronic display indicator'' to prevent
confusion since most instruments will be electronic. In proposed Sec.
23.1311(a)(7), we have added the word ``equivalent'' to make acceptable
instrument markings on electronic displays that are equivalent to those
instrument markings on conventional mechanical and electromechanical
instruments.
    In proposed Sec.  23.1311(b), we replace the phrase ``remain
available to the crew, without need for immediate action'' with ``be
available within one second to the crew with a single pilot action or
by automatic means.'' The proposed language allows an applicant to take
credit for reversionary or secondary flight displays on a multi-
function flight display (MFD) that provides a secondary means of
primary flight information (PFI). This is acceptable if the display can
``be available within one second to the crew with a single pilot action
or by automatic means.'' MFD's may also display PFI as needed to ensure
continuity of operations. The display of PFI on reversionary
(secondary) displays must be arranged in the basic T-configuration.
Also, such displays must be legible and usable from the pilot's
position with minimal head movement to meet the requirements of Sec.
23.1321.
    There are three acceptable methods for meeting the requirements of
Sec.  23.1311(b)--(1) Dedicated standby instruments, (2) dual primary
flight displays (PFDs), or (3) reversionary displays that display
independent attitude. The standby instruments, or another independent
PFD, would ensure that primary flight information is available to the
pilot during all phases of flight and system failures. The

electronic display systems with dual PFDs should incorporate dual,
independently-powered sensors that would provide primary flight
parameters (e.g., attitude heading reference system (AHRS) with
comparators and dual air data computer (ADC)). A reversionary
configuration would have a single pilot action that would force MFD
displays into reversionary mode operation by a single pilot action
within one second or less. However, the PFI must be displayed in
substantially the same format and size in the reversionary mode as it
is in normal mode. The single pilot action should be easily recognized,
readily accessible, and have the control within the pilot's primary
field of view.
    The reversionary method could include an automatic reversionary
display with a single pilot action. If PFI on another display is not
provided, we would require automatic switching to ensure PFI is
available to the pilot. This automatic reversionary capability would
cover most possible malfunctions. While a total loss of the display may
not be reliably detected automatically, such a failure condition would
be obvious to the pilot. Malfunctions that result in automatic
switching would be extensive enough to ensure PFI is available at the
reliability level required by Sec.  23.1309. If such a malfunction
occurs, a single pilot action would provide a full display of the
essential information on the remaining display within one second. All
modes, sources, frequencies, and flight plan data would be exactly as
they were on the PFD before the failure.
    Another reversionary method would include a means to access the
reversionary mode manually through a single pilot action. Manual
activation of the reversionary mode on the MFD through single action by
the pilot would be acceptable when procedures to activate the PFI are
accomplished before entering critical phases of flight. The PFI would
display continuously on the reversionary display during critical phases
of flight (e.g., takeoff, landing, and missed or final approach).
    To meet the proposed turbojet performance requirements in subpart
B, the pilot would need accurate speed indicators while accelerating on
the runway. We propose to revise Sec.  23.1323(e) to add the
requirement to calibrate the airspeed system down to 0.8 of the minimum
value of V1. Also, we propose to adopt the language used in
part 25 for this same requirement because it is more in line with
operating new part 23 turbojets.
    The proposed changes to Sec.  23.1331 would apply to instruments
that rely on a power source to provide required flight information for
instrument flight rules (IFR) operations. Consequently, this section
would apply to all flight instruments, such as those required by parts
23, 91, 121, and 135. Airplanes limited by type design to visual flight
rules (VFR) operations would not have to comply with the requirements
of proposed Sec.  23.1331(c).
    Each independent power source must provide sufficient power for
normal operations throughout the approved flight envelope of the
airplane and for any operations approved for the airplane. Section
23.1331(c) would not require the installation of dual alternators or
vacuum systems on single-engine airplanes. One option would include a
dedicated battery that meets the requirements of Sec.  23.1353(h) for
electrical instrument loads essential to continued safe flight and
landing. Another option would include separately powered instruments
for primary and standby use. The last option would include performing a
system safety analysis, per Sec.  23.1309, to identify the procedures
necessary to verify the charge state of any airplane starting battery
that is used to power a stand-by system.
    The ARC did not make a specific recommendation for Sec.  23.1353.
However, we propose to add additional battery endurance requirements
depending on the airplane's altitude performance. Proposed Sec.
23.1353 addresses the power needs of new all-electrical instruments,
navigation and communications equipment, and engine controls.
    When Sec.  23.1353(h) was adopted, part 23 airplanes were mostly
mechanical. We did not envision all-electric, or almost all-electric,
airplanes. Current Sec.  23.1353(h) requires 30 minutes of sufficient
electrical power for a reduced or emergency group of equipment and
instrumentation. We considered 30 minutes adequate to reach VFR
conditions to continue flying to an adequate airport and to accomplish
a safe landing for traditional part 23 airplanes. We did not envision
integrated electric cockpits when we developed Sec.  23.1353(h). New
part 23 airplanes are being certificated with all-electrical
instruments, including the standby instruments. This reliance on
electric power increases the importance of ensuring adequate battery
power until the pilot can descend and make a safe landing.
    Most new engines utilize electronic engine controls. These engine
controls may rely on the airplane's electrical system for power and to
control fuel and ignition. Large engines typically installed on part 25
airplanes have a dedicated power source running off the engine; as long
as the engine is running, the electronic engine control has power. Some
of the smaller, simpler engines emerging in part 23 airplanes may not
have these dedicated power sources and may rely on the airplane's
electrical system to keep functioning.
    We believe that most new turbine-powered airplanes, and some
turbocharged, piston-powered airplanes, will operate at high altitudes
under IFR. Under these conditions, 30 minutes may not be adequate for
battery power because of the time it would take to descend from maximum
altitude to find visual meteorological conditions (VMC) and land, or to
perform an instrument approach for a landing. For these reasons,
proposed Sec.  23.1353(h) would extend the battery time requirement to
60 minutes for airplanes approved with a maximum altitude above 25,000
feet.
    Many new single-engine airplanes are intended for use in part 135
passenger service. Proposed Sec.  23.1353(h) provides consistency with
the operating requirements for single-engine IFR in Sec.  135.163(i).
That section requires a 60-minute battery to power all emergency
equipment, as specified by the manufacturer, to allow continued safe
flight and landing.
b. Allowable Qualitative Failure Condition Probabilities
    We propose to add Appendix K to show the appropriate airplane
systems probability standards, failure conditions, and related
development assurance for four certification classes of airplanes
designed to part 23 standards. Proposed Appendix K includes development
assurance levels that correlate to the software levels in RTCA/DO-178B
and the complex design assurance levels in RTCA/DO-254. We provided
quantitative values in Appendix K to indicate the order of probability
range for each certification class and failure condition.
    As used in Sec.  23.1309, the FAA proposes the following
definitions for terms used in Appendix K:
    i. Extremely remote failure conditions: Those failure conditions
not anticipated to occur to each airplane during its total life but
which may occur a few times when considering the total operational life
of all airplanes of this type. For quantitative assessments, refer to
the probability values shown for hazardous failure conditions in
Appendix K.
    ii. Extremely improbable failure conditions: For commuter category
airplanes, those failure conditions so unlikely that they are not
anticipated to occur during the entire operational life of all
airplanes of one type. For other

classes of airplanes, the likelihood of occurrence may be greater. For
quantitative assessments, refer to the probability values shown for
catastrophic failure conditions in Appendix K.
    iii. Probable failure conditions: Those failure conditions
anticipated to occur one or more times during the entire operational
life of each airplane. These failure conditions may be determined on
the basis of past service experience with similar components in
comparable airplane applications. For quantitative assessments, refer
to the probability values shown for minor failure conditions in
Appendix K.
    iv. Remote failure conditions: Those failure conditions that are
unlikely to occur to each airplane during its total life but that may
occur several times when considering the total operational life of a
number of airplanes of this type. For quantitative assessments, refer
to the probability values shown for major failure conditions in
Appendix K.
    v. Design appraisal: A qualitative appraisal of the integrity and
safety of the system design. An effective appraisal requires
experienced judgment.
    vi. Development assurance level: All planned and systematic actions
used to substantiate, to an adequate level of confidence, that errors
in requirements, design, and implementation have been identified and
corrected such that the system satisfies the applicable certification
basis. (The development assurance levels in Appendix K are intended to
correlate to software levels in RTCA/DO-178B and complex hardware
design assurance levels in RTCA/DO-254 for the system or item.)
    vii. Simple and conventional systems: A system is considered
``simple'' or ``conventional'' if its function, the technological means
to implement its function, and its intended usage are all the same as,
or closely similar to, that of previously approved systems commonly
used. The systems that have established an adequate service history and
the means of compliance for approval are generally accepted as
``simple'' or ``conventional.'' Simple systems do not contain software
or complex hardware requiring compliance by documents. These documents
are the developmental assurance levels assigned in RTCA/DO-178A/B,
Software Considerations in Airborne Systems and Equipment
Certification, or RTCA/DO-254, Design Assurance Guidance for Airborne
Electronic Hardware documents or later versions.
    For simple and conventional installations, it may be possible to
assess a hazardous or catastrophic failure condition(s) as being
extremely remote or extremely improbable, respectively, based on an FAA
approved qualitative analysis. The basis for the assessment would be
the degree of redundancy, the established independence and isolation of
the channels, and the reliability record of the technology involved.
Satisfactory service experience on similar systems commonly used in
many airplanes may be sufficient when a close similarity is established
regarding both the system design and operating conditions.
    viii. Installation appraisal: A qualitative appraisal of the
integrity and safety of the installation. Any deviations from normal
industry-accepted installation practices should be evaluated.

8. Placards, Speeds, Operating Limitations, and Information

    Currently, Sec.  23.853(d)(2) requires placards for commuter
category airplanes to have red letters at least \1/2\ inch high on a
white background at least 1 inch high. The letter size is not a
requirement for the part 23 normal category or for the part 25
transport category airplanes. We propose removing the letter size
requirement from this section. We also propose removing the ashtray
requirement from this section since smoking is no longer allowed in
parts 121 and 135 operations. We propose to amend paragraph (d)(2) of
this section to read ``Lavatories must have `No Smoking' or `No Smoking
in Lavatory' placards located conspicuously on each side of the entry
door.''
    Proposed Sec.  23.629 would allow the use of VDF in
place of VD for flight testing turbojets. In addition, the
proposed amendment for Sec.  23.1505 would require airspeed limits
based on a combination of analytical (VD/MD) and
demonstrated (VDF/MDF) dive speeds for turbojets.
Proposed Sec.  23.1505(c) would include specific turbojet speed
designations.
    The ARC did not make a specific recommendation regarding Sec.
23.1525. However, we propose to clarify language so applicants
understand that additional equipment may be needed to operate their
airplane. Part 23 is a minimum performance standard, and it may not
include all the required equipment for operations under part 135. We
propose to include parts 91 and 135 operations as examples of the kinds
of operation authorized.
    Proposed Sec.  23.1545 limits the white flap arc to reciprocating
engine airplanes. This change reflects standard practice for turbojets
and is included in all part 23 turbojet special conditions.
    Proposed Sec.  23.1555(d)(3) would require fuel systems with a
calibrated fuel quantity indication system to comply with Sec.
23.1337(b)(1) while removing current placard requirements. Most modern
turbine-powered airplanes have a calibrated fuel quantity indicating
system that is density compensated and accurately indicates the actual
usable fuel quantity in each tank. When using these types of fuel
indicating systems, we consider the placards required by Sec. Sec.
23.1555(d)(1) and (2) redundant. The placards or markings required by
Sec. Sec.  23.1555(d)(1) and (2) indicate the maximum capacity of the
tank. For these reasons, we propose to remove the placard requirement
for these accurate fuel quantity indicating systems.
    The placard requirements of Sec. Sec.  23.1559, 23.1563 and 23.1567
have been a source of confusion to both FAA and industry personnel
relative to placard lighting. We are proposing changes to these three
rules to clarify the intent of these requirements. The requirements
specified on the placard in Sec.  23.1559 are relative to preflight
planning, and this placard is not normally referenced in flight. As
long as the placard is ``in clear view of the pilot'' and the pilot can
view it at night using a flashlight or other means, the intent of the
rule is met. The requirement has been confusing for certification
offices and this proposal makes the placard lighting intent clear. We
propose to add a new paragraph Sec.  23.1559(d), which states ``The
placard required by this section need not be lighted.''
    With modern flight display equipment, the necessary information may
now be available on that equipment and is automatically illuminated as
part of the display. Therefore, we also propose to update Sec.  23.1563
to clarify requirements for night lighting of the placard. Maneuvering
speed is applicable to operations that may involve intentional large
control input and is therefore not applicable to normal night
operations. Most modern airplanes have means for the landing gear speed
to be displayed in the airspeed indicator or on lighted portions of the
landing gear control. They have the means for the airspeed indicator to
display low speed awareness or other airspeed reference information to
provide safety above VMC. Lighting this placard is
unnecessary for safety and provides another source of unwanted lighting
reflections in the cockpit.
    The requirements specified in Sec.  23.1567 for the limitation
placard relate to acrobatic maneuvers and spin information related to
preflight

planning. Since these maneuvers are not normally conducted during night
operations, the placard information is not required for night flight.
If the placard is ``in clear view of the pilot'' and the pilot can view
the placard at night using a flashlight or other means, it meets the
intent of the rule. The proposed change to Sec.  23.1567 clarifies our
intent of this rule relative to lighting.
    We propose to incorporate the existing special conditions into the
AFM requirements in Sec. Sec.  23.1583, 23.1585, and 23.1587. These are
necessary to be consistent with the performance requirements proposed
in subpart B. These requirements include the ARC recommended, single-
engine climb performance increase for turboprops.

III. Regulatory Notices and Analyses

Paperwork Reduction Act

    According to the 1995 amendments to the Paperwork Reduction Act (5
CFR 1320.8(b)(2)(vi)), an agency may not collect or sponsor the
collection of information, nor may it impose an information collection
requirement unless it displays a currently valid OMB control number.
The OMB control number for this information collection will be
published in the Federal Register, after the Office of Management and
Budget approval.

International Compatibility

    In keeping with U.S. obligations under the Convention on
International Civil Aviation, it is FAA policy to comply with
International Civil Aviation Organization (ICAO) Standards and
Recommended Practices to the maximum extent practicable. The FAA has
reviewed the corresponding ICAO Standards and Recommended Practices and
has identified no differences with these proposed regulations.

Regulatory Evaluation, Regulatory Flexibility Determination,
International Trade Impact Assessment, and Unfunded Mandates Assessment

    Changes to Federal regulations must undergo several economic
analyses. First, Executive Order 12866 directs that each Federal agency
shall propose or adopt a regulation only upon a reasoned determination
that the benefits of the intended regulation justify its costs. Second,
the Regulatory Flexibility Act of 1980 (Pub. L. 96-354) requires
agencies to analyze the economic impact of regulatory changes on small
entities. Third, the Trade Agreements Act (Pub. L. 96-39) prohibits
agencies from setting standards that create unnecessary obstacles to
the foreign commerce of the United States. In developing U.S.
standards, this Trade Act requires agencies to consider international
standards and, where appropriate, that they be the basis of U.S.
standards. Fourth, the Unfunded Mandates Reform Act of 1995 (Pub. L.
104-4) requires agencies to prepare a written assessment of the costs,
benefits, and other effects of proposed or final rules that include a
Federal mandate likely to result in the expenditure by State, local, or
tribal governments, in the aggregate, or by the private sector, of $100
million or more annually (adjusted for inflation with base year of
1995). This portion of the preamble summarizes the FAA's analysis of
the economic impacts of this proposed rule. We suggest readers seeking
greater detail read the full regulatory evaluation, a copy of which we
have placed in the docket for this rulemaking.
    In conducting these analyses, FAA has determined that this proposed
rule: (1) Has benefits that justify its costs, (2) is not an
economically ``significant regulatory action'' as defined in section
3(f) of Executive Order 12866, (3) the Office of Management and Budget
has determined this proposal is ``significant''; (4) would not have a
significant economic impact on a substantial number of small entities;
(5) would not create unnecessary obstacles to the foreign commerce of
the United States; and (6) would not impose an unfunded mandate on
state, local, or tribal governments, or on the private sector by
exceeding the threshold identified above. These analyses are summarized
below.
Total Benefits and Costs of This Rule
    The estimated base case cost of this proposed rule is about
$472,000 ($443,000 in 7 percent present value terms). The estimated
safety benefits would be to avoid 14 accidents and are valued at about
$82.7 million. The estimated base case efficiency benefits to
streamline the part 23 certification process are valued at about $1.6
million. The total base case benefit is equal to the sum of the safety
and efficiency benefits and is valued at about $84.2 million.
Who Is Potentially Affected by This Rule
    This proposed rulemaking will affect manufacturers and operators of
part 23 reciprocal engine, turboprop and turbojet airplanes.

Assumptions

    The proposed rule makes the following assumptions:
    1. The base year is 2008.
    2. The average retirement age of a U.S. operated part 23 airplane
is 32 years.
    3. The average part 23 airplane production life cycle is 24 years.
    4. The analysis period extends for 56 (32 + 24) years.
    5. U.S companies would manufacture 75 percent of the turbojets
forecasted by the FAA.
    6. All business and commercial part 23 airplanes would operate in
commuter service.
    7. The value of a fatality avoided is $5.8 million.

Benefits of This Rule

    For part 23 airplanes, we estimated that the proposed changes would
avoid about 14 accidents over the 24-year operating lives of 37,657
new-production airplanes. The resulting benefits include averted
fatalities and injuries, loss of airplanes, investigation cost, and
collateral damages for the accidents. The safety benefits for averting
the 14 accidents are about $82.7 million ($17.8 million in 7 percent
present value terms).
    Other benefits of this proposal include FAA and industry paperwork
and certification time saved by standardizing and streamlining the
certification of part 23 airplanes. The base case efficiency benefits
for standardizing and streamlining the certification process is valued
at $1.6 million.
    The total base case benefit is equal to the sum of the safety and
efficiency benefits and is about $84.2 million ($19.3 million in 7
percent present value terms).

Costs of This Rule

    Constant-dollar (2008$) unit costs per aircraft by 14 CFR Part 23
could be as high as: $165 for turboprop airplanes and $6,550 for
turbojet airplanes. Total incremental costs equal the constant-dollar
unit costs multiplied by the number of aircraft produced over 10 years.
The base case costs of this rule are about $472,000 ($443,000 in 7
percent present value terms) and the high case costs of this rule are
about $11.1 million ($5.0 million in 7 percent present value terms).

Alternatives Considered

    Alternative 1--The FAA would continue to issue special exemptions,
exceptions and equivalent levels of safety to certificate part 23
airplanes. As that would perpetuate ``rulemaking by exemption,'' we
choose not to continue with the status quo.
    Alternative 2--The FAA continue to enforce the current regulations
that affect single engine climb performance.

The FAA rejected this alternative because the accident rate on twin
piston engine and turboprop airplanes identified a safety issue that
had to be addressed.

Regulatory Flexibility Determination

    The Regulatory Flexibility Act of 1980 (Pub. L. 96-354) (RFA)
establishes ``as a principle of regulatory issuance that agencies shall
endeavor, consistent with the objectives of the rule and of applicable
statutes, to fit regulatory and informational requirements to the scale
of the businesses, organizations, and governmental jurisdictions
subject to regulation. To achieve this principle, agencies are required
to solicit and consider flexible regulatory proposals and to explain
the rationale for their actions to assure that such proposals are given
serious consideration.'' The RFA covers a wide-range of small entities,
including small businesses, not-for-profit organizations, and small
governmental jurisdictions.
    Agencies must perform a review to determine whether a rule will
have a significant economic impact on a substantial number of small
entities. If the agency determines that it will, the agency must
prepare a regulatory flexibility analysis as described in the RFA.
However, if an agency determines that a rule is not expected to have a
significant economic impact on a substantial number of small entities,
section 605(b) of the RFA provides that the head of the agency may so
certify and a regulatory flexibility analysis is not required. The
certification must include a statement providing the factual basis for
this determination, and the reasoning should be clear.
    The FAA believes that this proposed rule would not have a
significant impact on a substantial number of entities. The purpose of
this analysis is to provide the reasoning underlying the FAA
determination.
    First, we will discuss the reasons why the FAA is considering this
action. We will follow with a discussion of the objective of, and legal
basis for, the proposed rule. Next we explain there are no relevant
federal rules which may overlap, duplicate, or conflict with the
proposed rule. Lastly, we will describe and provide an estimate of the
number of small entities affected by the proposed rule and why the FAA
believes this proposed rule would not result in a significant economic
impact on a substantial number of small entities.
    We now discuss the reasons why the FAA is considering this action.
    The FAA proposes this action to amend safety and applicability
standards of the part 23 turbojet industry to reflect the current needs
of the industry, accommodate future trends, address emerging
technologies, and provide for future aircraft operations. This proposal
primarily standardizes and streamlines the certification of part 23
turbojet airplanes. The intent of the proposed changes to parts 1 and
23 are necessary to eliminate the current workload of exemptions,
special conditions, and equivalent levels of safety determinations
necessary to certificate part 23 turbojets. These proposed part 23
changes will also clarify areas of frequent non-standardization and
misinterpretation and provide appropriate safety and applicability
standards that reflect the current state of the industry, emerging
technologies and new types of operations for all part 23 airplanes;
including turbojet, turboprop and reciprocating engine airplanes.
    The FAA currently issues type certificates (TCs) for part 23
turbojets using extensive special conditions. Issuance of TCs has not
been significant until now because there were few part 23 turbojet
programs. However, in the past five years, the number of new turbojet
certification programs in part 23 has increased more than 100 percent
over the past three decades.
    The need to incorporate these special conditions into part 23 stems
from both the existing number of new jet programs and the expected
future jet programs. Codifying these special conditions will allow
manufacturers to know the requirements during their design phase
instead of designing the turbojet and then having to apply for special
conditions that may ultimately require a redesign. Codifying will also
reduce the manufacturers and FAA's paper process required to TC an
airplane and reduces the potential for program delays. These proposed
changes would also clarify areas of frequent non-standardization and
misinterpretation, particularly for electronic equipment and system
certification.
    The revisions include general definitions, error correction, and
specific requirements for performance and handling characteristics to
ensure safe operation of part 23 transport category airplanes. The
proposed revisions would apply to all future new part 23 turbojet,
turboprop and reciprocating engine airplane certifications.
    We now discuss the legal basis for, and objective of, the proposed
rule. Next, we discuss if there are relevant federal rules, which may
overlap, duplicate, or conflict with the proposed rule.
    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 aircraft in air
commerce by prescribing minimum standards required in the interest of
safety for the design and performance of aircraft. This regulation is
within the scope of that authority because it prescribes new safety
standards for the design of part 23 normal, utility, acrobatic, and
commuter category airplanes.
    Accordingly, this proposed rule will amend Title 14 of the Code of
Federal Regulations to address deficiencies in current regulations
regarding the certification of part 23 light jets, turboprops and
reciprocating engine airplanes. The proposed rule would clarify areas
of frequent non-standardization and misinterpretation and codify
certification requirements that currently exist in special conditions.
    The FAA is unaware the proposed rule will overlap, duplicate, or
conflict with existing Federal Rules.
    We now discuss our methodology to determine the number of small
entities for which the proposed rule will apply.
    Under the RFA, the FAA must determine whether a proposed rule
significantly affects a substantial number of small entities. This
determination is typically based on small entity size and cost
thresholds that vary depending on the affected industry.
    Using the size standards from the Small Business Administration for
Air Transportation and Aircraft Manufacturing, we defined companies as
small entities if they have fewer than 1,500 employees.\6\
---------------------------------------------------------------------------

    \6\ 13 CFR 121.201, Size Standards Used to Define Small Business
Concerns, Sector 48-49 Transportation, Subsector 481 Air
Transportation.
---------------------------------------------------------------------------

    There are 11 U.S. aircraft manufacturers currently producing part
23 airplanes and could be affected by this proposal. These
manufacturers are American Champion, Cessna, Cirrus, Eclipse, Hawker
Beechcraft, Liberty, Maule, Mooney, Piper, Quest, and Sino Swearingen.
    Using information provided by the World Aviation Directory,
Internet filings and industry contacts, manufacturers that are
subsidiary

businesses of larger businesses, manufacturers that are foreign owned,
and businesses with more than 1,500 employees were eliminated from the
list of entities. Cessna and Hawker Beechcraft are businesses with more
than 1,500 employees and Cirrus and Liberty are foreign owned. We found
no source of employment or revenue data for American Champion. For the
remaining businesses, we obtained company revenue and employment from
the above sources.
    The base year for the proposed rule is 2008. Although the FAA
forecasts traffic and air carrier fleets, we can not determine the
number of new entrants nor who will be in business in the future.
Therefore we use current U.S. manufacturer's revenue and employment in
order to determine the number of operators this proposal would affect.
    The methodology discussed above resulted in the following six U.S.
part 23 aircraft manufacturers, with less than 1,500 employees, shown
in Table RF1.

                                Table RF1
------------------------------------------------------------------------
                Company                    Employees     Annual revenue
------------------------------------------------------------------------
Quest.................................              60        $4,600,000
Maule.................................              86         5,700,000
Piper.................................             100         7,600,000
Mooney................................             400        42,083,000
Sino Swearingen.......................             400        25,300,000
Eclipse...............................           1,000        36,700,000
------------------------------------------------------------------------

    The majority of this proposal affects the certification of
turbojets and has a minor affect on the certification of turboprop and
reciprocating engine airplanes by clarifying frequent non-
standardization and misinterpretations of the current part 23 rules.
    From the list of part 23 small entity U.S. airplane manufacturers
above, only Eclipse and Sino Swearingen produce turbojet airplanes and
Piper and Quest produce turboprop airplanes. The remaining part 23
small entity U.S. airplane manufacturers produce reciprocating engine
airplanes.
    In the regulatory evaluation, we estimated that operators of newly
certificated part 23 airplanes would incur additional fuel costs.
Additionally, operators could incur costs from added weight and a
reduced payload capacity. The U.S. Census Bureau data on the Small
Business Administration's Web site shows an estimate of the total
number of small business entities who could be affected if they
purchase newly certificated part 23 airplanes.\7\ The U.S. Census
Bureau data lists 39,754 small entities in the Non-scheduled Air
Transportation Industry that employ less than 500 employees. Many of
these non-scheduled businesses are in part 25. Other small businesses
may own aircraft and not be included in the U.S. Census Bureau Non-
scheduled Air Transportation Industry category. The estimate of the
affect of this proposal on the total number of small entities that
operate part 23 airplanes is developed below.
---------------------------------------------------------------------------

    \7\ http://www.sba.gov/advo/research/us05_n6.pdf.
---------------------------------------------------------------------------

    We now discuss our methodology to estimate the costs of this
proposal to the small entities part 23 airplane manufacturers and
operators. We will also discuss why the FAA believes this proposed rule
would not result in a significant economic impact to part 23 airplane
manufacturers and operators.
    In 2003, we published a notice (68 FR 5488) creating the part 125/
135 Aviation Rulemaking Committee (ARC). FAA and the part 23 industry
have worked together to develop common certification part 23 airplane
requirements proposed in this rulemaking. We contacted the part 23
aircraft manufacturers, the ARC, and General Aviation Manufacturers
Association (GAMA) (an industry association for part 23 aircraft
manufacturers) for specific cost estimates for each proposed section
change for this rule. Not every party we contacted responded to our
request for costs. Many of the ARC members, from the domestic and
international manufacturing community, collaborated and filed a joint
cost estimate for this proposed rule. We are basing our cost estimates
for this proposed rule from these part 23 U.S. aircraft manufacturers,
ARC members and GAMA.
    The part 23 U.S. airplane manufacturers, ARC members, and industry
association informed us that this proposed rulemaking would add
manufacturer certification costs for fire extinguishing systems, climb,
and take-off warning systems. Industry informed us that this proposal
would save the manufacturers design time for the certification of
cockpit controls. Industry has also informed us that every other
proposed section of this rule is either clarifying, error correcting,
or would only add minimal to no costs.
    The proposed rule adds certification requirements for the following
part 23 airplane categories:
    1. All turbojet airplanes,
    2. All turbojet airplanes with a MTOW less than 6,000 pounds,
    3. All turboprop airplanes,
    4. All reciprocal engine airplanes, and
    5. All reciprocal twin engine airplanes with a MTOW greater than
6,000 pounds.
    In some cases the proposed regulations only affect part 23
airplanes operated in revenue service. Any part 23 airplane could be
used as a business airplane to haul passengers and cargo in commercial
service. We estimated the business versus personal use of a part 23
airplane by analyzing the number of all US-operated airplanes from
Table 3.1 of the 2006 General Aviation and Part 135 Activity Survey.
Table 3.1 shows the breakout of the 2006 General Aviation fleet by
business, corporate, instructional, aerial applications, aerial
observations, aerial other, external load, other work, sight see, air
medical, other, part 135 Air Taxi, Air Tours, and Air Medical airplane
usage. For the purpose of estimating the cost of this proposal, we
assume all business part 23 airplane operators from Table 3.1 of the
2006 General Aviation and Part 135 Activity Survey would operate in
Commuter service. Table RF2 shows these results.

                    Table RF2--2006 General Aviation and Part 135 Activity Survey--Table 3.1
----------------------------------------------------------------------------------------------------------------
                  Aircraft type                    Total active      Personal       % Personal      % Business
----------------------------------------------------------------------------------------------------------------
Piston..........................................         163,743         118,618           72.44           27.56
Turboprop.......................................           8,063           1,177           14.60           85.40
Turbojet........................................          10,379             750            7.23           92.77
----------------------------------------------------------------------------------------------------------------

    Table RF3 shows the results of the proposed sections that add (or
subtract) incremental costs by increasing design or flight testing
times, adds weight, or reducing payload.

                                                                                Table RF3
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                     Certification        Flight Operation                            Part 23 Airplane Categories Affected
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Twin
                                                                                Turbojet                           reciprocal
                                                                   Design     Flight   Additional    Payload                 <6,000                Reciprocal    engine
           Part 23 Section                   Section title         hours       test      weight     reduction   Turbojet       Turboprop    engine      >6,000           Category
                                                                              hours                                           MTOW
                                                                                MTOW
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
23.1193(g), 23.1195(a), 23.1197,       Cowling and Nacelle,      .........         50          25  ..........  ..........  ..........          X   ..........  ..........  Commuter.
 23.1199, 23.1201.                      Fire Extinguisher
                                        Systems, Fire
                                        Extinguishing Agents,
                                        Extinguishing Agent
                                        Containers, Fire
                                        Extinguishing System
                                        Materials.
23.63, 23.67, 23.77..................  Climb: General, Climb--   .........  .........  ..........        10%   ..........          X           X   ..........          X   All.
                                        One Engine, Balked
                                        Landing.
23.703...............................  Take-Off Warning System.      1,000         25  ..........  ..........  ..........          X           X   ..........          X   All.
23.777...............................  Cockpit Controls........        -25  .........  ..........  ..........          X   ..........          X           X   ..........  All.
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimated part 23 airplane manufacturer fixed (added
certification plus flight test hours) and operator variable (added fuel
burn plus 10 percent reduction in payload) costs and applied our
estimated costs to expected fleet delivered in compliance with this
proposal. The total cost of this rule is the sum of the fixed
certification cost plus the airplane fuel-burn variable cost multiplied
by the expected fleet delivered over the analysis period.
    The total fixed certification compliance cost equals the average
compliance cost multiplied by the expected number of certifications of
newly delivered part 23 turbojet, turboprop and reciprocating engine
airplane. In the regulatory evaluation we estimated a base case and
high case range for the certification costs. This range was based on
the estimated number of new turbojet certifications. In the base case,
we estimated five new turbojet certifications in the analysis interval.
In the high case, we estimated eight new turbojet certifications. We
will use the high cost case scenario for this analysis.
    We estimated the certification costs for fire extinguishing
systems, climb, and take-off warning systems. Based on the hours
provided by the part 23 U.S. airplane manufacturers, ARC members and
industry association and the Economic Values For FAA Investment and
Regulatory Decisions, A Guide for the hourly rates.\8\ Table RF4 shows
the incremental certification costs estimate we calculated.
---------------------------------------------------------------------------

    \8\ http://www.faa.gov/regulations_policies/policy_guidance/
benefit_cost/media/
050404%20Critical%20Values%20Dec%2031%20Report%2007Jan05.pdf.

                             Table RF4--High Cost Scenario for Part 23 Manufacturers
----------------------------------------------------------------------------------------------------------------
                              Costs                                    Recip        Commuter TP     TJ < 6,000
----------------------------------------------------------------------------------------------------------------
Design..........................................................              $0        $152,020         $94,496
Design..........................................................         (9,501)         (3,801)        (22,803)
Flight Test.....................................................               0         114,400          93,489
Total High Cost.................................................         (9,501)         262,620         165,181
 Certifications........................................               5               4              12
Cost per Cert...................................................         (1,900)          65,655          13,765
----------------------------------------------------------------------------------------------------------------

    We applied the estimated incremental certification costs to the
each of the small part 23 airplane manufacturing average number of
historical certifications over a ten-year period. We then divided the
small part 23 airplane

manufacturer's annual revenue by the incremental costs. Table RF5 shows
these results.

                                                                        Table RF5
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                    Annual       Average  certs 10                               Estimated cert
            Company                Employees        revenue                years                Airplane certificated          cost           Percent
--------------------------------------------------------------------------------------------------------------------------------------------------------
Quest.........................              60      $4,600,000  1.00.......................  Turboprop..................         $65,655            1.43
Maule.........................              86       5,700,000  0.20.......................  Recip......................            -380           -0.01
Piper.........................             100       7,600,000  1.00 (Recip) + 33 (TP).....  Recip + Turboprop..........          65,022            0.86
Mooney........................             400      42,083,000  0.17.......................  Recip......................            -317            0.00
Sino Swearingen...............             400      25,300,000  1.00.......................  Turbojet...................          13,765            0.05
Eclipse.......................           1,000       36,700,00  1.00.......................  Turbojet...................          13,765            0.04
--------------------------------------------------------------------------------------------------------------------------------------------------------

    We estimated that the incremental fixed certification cost this
proposed rule would be less than one percent in five of the six small
entity part 23 airplane manufacturers, and less than 1.5 percent in the
remaining one. We do not believe these are significant economic costs.
Further, we believe that the manufacturers of the part 23 airplanes
would have additional costs savings associated with the proposal
standardizes and streamlining the certification process. Additional
costs savings of the proposed changes to parts 1 and 23 would be to
eliminate the current workload of exemptions, special conditions, and
equivalent levels of safety necessary to certificate part 23 turbojets
and by clarifying frequent non-standardization and misinterpretations
of current part 23 rules.
    To estimate the incremental variable costs to a part 23 operator,
we multiplied the annual per-unit fuel burn cost by the expected fleet
delivered over the analysis interval.
    In the regulatory evaluation, we estimated a minimal base and high
case cost for the 10 percent loss in capacity occurs the operators may
incur. The base case was a no cost scenario because the average GA
airplane has about 3.7 seats and flies about half full.\9\ The cargo
load factor for all cargo carriers is 60 percent.\10\ Therefore, we
conclude that the 10 percent reduction in payload caused by the
proposed sections on climb and balked landings could have a minimum
cost impact on part 23 airplanes for the base case. For the high case
we realize that a percentage of the part 23 airplanes, in commuter
service, could have a load factor over 90 percent on some of their
flights. Although we believe any capacity affected would be distributed
over other flights in the operator's network, we estimate the cost of a
10 percent payload capacity reduction. Table RF6 shows the results of
our calculations.
---------------------------------------------------------------------------

    \9\ Table 3.15 of the Economic Values For FAA Investment and
Regulatory Decisions, A Guide
    \10\ Ibid.

                                                    Table RF6
----------------------------------------------------------------------------------------------------------------
                                       Recip         TurboProp      Commuter TP      Total TJ        TJ<6,000
----------------------------------------------------------------------------------------------------------------
Base Case Cost..................              $0              $0          $8,430              $0              $0
High Case Cost..................              $0              $0      $1,413,692              $0      $3,086,919
Number of A/P...................          23,160           1,248           1,066          11,040           1,143
Base Case Cost / A/P............              $0              $0              $8              $0              $0
High Case Cost / A/P............              $0              $0          $1,326              $0          $2,700
A/P Value.......................        $431,681      $3,389,054      $3,389,054      $6,300,000      $6,300,000
% Base of Value.................           0.00%           0.00%           0.00%           0.00%           0.00%
% High of Value.................           0.00%           0.00%           0.04%           0.00%           0.04%
----------------------------------------------------------------------------------------------------------------

    For this proposal, our high case estimate for small business part
23 operators of turboprop airplanes would pay an additional $1,326 to
operate a newly certificated airplane. Operators of newly certificated
and delivered part 23 turbojet airplanes with a maximum take off weight
less than 6,000 pounds would pay an additional $2,700 to operate a
newly certificated airplane. Operators would not incur these costs
unless they purchase a newly certificated part 23 airplane.
    We do not believe that these proposals costs would be a significant
impact to small entity operators because, even for the high-cost case,
the compliance costs of this proposal to operators would only be 0.04
percent for a turboprop and 0.04 percent for a turbojet with a maximum
take-off weight less than 6,000 pounds, of the price of a newly
certificated airplane.
    Therefore the FAA certifies that this proposed rule would not have
a significant economic impact on a substantial number of small
entities. The FAA solicits comments regarding this determination.

International Trade Impact Assessment

    The Trade Agreements Act of 1979 (Pub. L. 96-39) prohibits Federal
agencies from establishing any standards or engaging in related
activities that create unnecessary obstacles to the foreign commerce of
the United States. Legitimate domestic objectives, such as safety, are
not considered unnecessary obstacles. The statute also requires
consideration of international standards and, where appropriate, that
they be the basis for U.S. standards. The FAA has assessed the
potential effect of this final rule and has no basis for believing the
rule will impose substantially different costs on domestic and
international entities. Thus the FAA believes the rule has a neutral
trade impact.

Unfunded Mandates Assessment

    Title II of the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-
4) requires each Federal agency to prepare

a written statement assessing the effects of any Federal mandate in a
proposed or final agency rule that may result in an expenditure of $100
million or more (in 1995 dollars) in any one year by State, local, and
tribal governments, in the aggregate, or by the private sector; such a
mandate is deemed to be a ``significant regulatory action.'' The FAA
currently uses an inflation-adjusted value of $136.1 million in lieu of
$100 million. This proposed rule does not contain such a mandate;
therefore, the requirements of Title II of the Act do not apply.

Executive Order 13132, Federalism

    The FAA has analyzed this proposed rule under the principles and
criteria of Executive Order 13132, Federalism. We determined that this
action would not have a substantial direct effect on the States, on the
relationship between the national Government and the States, or on the
distribution of power and responsibilities among the various levels of
government, and, therefore, would not have federalism implications.

Regulations Affecting Intrastate Aviation in Alaska

    Section 1205 of the FAA Reauthorization Act of 1996 (110 Stat.
3213) requires the Administrator, when modifying regulations in Title
14, Code of Federal Regulations in a manner affecting intrastate
aviation in Alaska, to consider the extent to which Alaska is not
served by transportation modes other than aviation and to establish
appropriate regulatory distinctions. Because this proposed rule would
apply to the certification of future designs of transport category
airplanes and their subsequent operation, it could, if adopted, affect
intrastate aviation in Alaska. The FAA, therefore, specifically
requests comments on whether there is justification for applying the
proposed rule differently in intrastate operations in Alaska.

Environmental Analysis

    FAA Order 1050.1E identifies FAA actions that are categorically
excluded from preparation of an environmental assessment or
environmental impact statement under the National Environmental Policy
Act in the absence of extraordinary circumstances. The FAA has
determined this proposed rulemaking action qualifies for the
categorical exclusion identified in paragraph 312(f) and involves no
extraordinary circumstances.

Regulations That Significantly Affect Energy Supply, Distribution, or
Use

    The FAA has analyzed this NPRM under Executive Order 13211, Actions
Concerning Regulations that Significantly Affect Energy Supply,
Distribution, or Use (May 18, 2001). We have determined that it is not
a ``significant energy action'' under the executive order because while
it is a ``significant regulatory action,'' it is not likely to have a
significant adverse effect on the supply, distribution, or use of
energy.

Additional Information

Comments Invited
    The FAA invites interested persons to participate in this
rulemaking by submitting written comments, data, or views. We also
invite comments relating to the economic, environmental, energy, or
federalism impacts that might result from adopting the proposals in
this document. The most helpful comments reference a specific portion
of the proposal, explain the reason for any recommended change, and
include supporting data. To ensure the docket does not contain
duplicate comments, please send only one copy of written comments, or
if you are filing comments electronically, please submit your comments
only one time.
    We will file in the docket all comments we receive, as well as a
report summarizing each substantive public contact with FAA personnel
concerning this proposed rulemaking. Before acting on this proposal, we
will consider all comments we receive on or before the closing date for
comments. We will consider comments filed after the comment period has
closed if it is possible to do so without incurring expense or delay.
We may change this proposal in light of the comments we receive.
Proprietary or Confidential Business Information
    Do not file in the docket information that you consider to be
proprietary or confidential business information. Send or deliver this
information directly to the person identified in the FOR FURTHER
INFORMATION CONTACT section of this document. You must mark the
information that you consider proprietary or confidential. If you send
the information on a disk or CD ROM, mark the outside of the disk or CD
ROM, and also identify electronically within the disk or CD ROM the
specific information that is proprietary or confidential.
    Under 14 CFR 11.35(b), when we are aware of proprietary information
filed with a comment, we do not place it in the docket. We hold it in a
separate file to which the public does not have access, and we place a
note in the docket that we have received it. If we receive a request to
examine or copy this information, we treat it as any other request
under the Freedom of Information Act (5 U.S.C. 552). We process such a
request under the DOT procedures found in 49 CFR part 7.
Availability of Rulemaking Documents
    You can get an electronic copy of rulemaking documents using the
Internet by--
    1. Searching the Federal eRulemaking Portal (http://
www.regulations.gov);
    2. Visiting the FAA's Regulations and Policies web page at http://
www.faa.gov/regulations_policies/; or
    3. Accessing the Government Printing Office's Web page at http://
www.gpoaccess.gov/fr/index.html.
    You can also get a copy by sending a request to the Federal
Aviation Administration, Office of Rulemaking, ARM-1, 800 Independence
Avenue SW., Washington, DC 20591, or by calling<PHONE_NUMBER>. Make sure
to identify the docket number or notice number of this rulemaking.
    You may access all documents the FAA considered in developing this
proposed rule, including economic analyses and technical reports, from
the Internet through the Federal eRulemaking Portal referenced in
paragraph (1).

List of Subjects

14 CFR Part 1

    Air transportation.

14 CFR Part 23

    Aviation Safety, Signs, Symbols, Aircraft.

The Proposed Amendments

    In consideration of the foregoing, the Federal Aviation
Administration proposes to amend Chapter I of Title 14, Code of Federal
Regulations, as follows:

PART 1--DEFINITIONS AND ABBREVIATIONS

    1. The authority citation for part 1 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.

    2. Revise the definitions of ``Rated takeoff power'' and ``Rated
takeoff thrust'' and add the definitions of ``Turbine engine'',
``Turbojet engine'', and ``Turboprop engine'' in alphabetical order in
Sec.  1.1 to read as follows:

Sec.  1.1  General definitions.

* * * * *

    Rated takeoff power, with respect to reciprocating, turbopropeller,
and turboshaft engine type certification, means the approved brake
horsepower that is developed statically under standard sea level
conditions, within the engine operating limitations established under
part 33 of this chapter, and limited in use--
    (1) To periods of not more than 5 minutes for takeoff operations
with reciprocating, turbopropeller, and turboshaft engines; and
    (2) When specifically requested by the engine manufacturer, to
periods of not more than 10 minutes for one-engine-inoperative takeoff
operations with turbopropeller engines.
    Rated takeoff thrust, with respect to turbojet engine type
certification, means the approved turbojet thrust that is developed
statically under standard sea level conditions, without fluid injection
and without the burning of fuel in a separate combustion chamber,
within the engine operating limitations established under part 33 of
this chapter, and limited in use--
    (1) To periods of not more than 5 minutes for takeoff operations;
and
    (2) When specifically requested by the engine manufacturer, to
periods of not more than 10 minutes for one-engine-inoperative takeoff
operations.
* * * * *
    Turbine engine, with respect to part 23 airplane type
certification, consists of an air compressor, a combustion section, and
a turbine. Thrust is produced by increasing the velocity of the air
flowing through the engine.
    Turbojet engine, with respect to part 23 airplane type
certification, is a turbine engine which produces its thrust entirely
by accelerating the air through the engine.
    Turboprop engine, with respect to part 23 airplane type
certification, is a turbine engine which drives a propeller through a
reduction gearing arrangement. Most of the energy in the exhaust gases
is converted into torque, rather than using its acceleration to drive
the airplane.
* * * * *

PART 23--AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND
COMMUTER CATEGORY AIRPLANES

    3. The authority citation for part 23 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701-44702, 44704.

    4. Amend Sec.  23.3 by revising the first sentence in paragraph (d)