[Federal Register Volume 84, Number 197 (Thursday, October 10, 2019)]
[Rules and Regulations]
[Pages 54476-54480]
[FR Doc No: 2019-22118]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2019-0805; Special Condition No. 23-298-SC]

Special Conditions: Diamond Aircraft Industries of Canada Model
DA-62 Airplanes; Diesel Cycle Engine Installation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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

SUMMARY: These special conditions are issued for the Diamond Aircraft
Industries of Canada DA-62 airplane. This airplane will have novel or
unusual design features associated with the installation of a diesel
cycle engine utilizing turbine fuel. The applicable airworthiness
regulations do not contain adequate or appropriate safety standards for
this design feature. These special conditions contain the additional
safety standards the Administrator considers necessary to establish a
level of safety equivalent to that established by the existing
airworthiness standards.

DATES: These special conditions are effective October 10, 2019.
    The FAA must receive your comments by November 12, 2019.

ADDRESSES: Send comments identified by docket number FAA-2019-0805
using any of the following methods:
    [square] Federal eRegulations Portal: Go to http://www.regulations.gov and follow the online instructions for sending your
comments electronically.
    [square] Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE. Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
    [square] Hand Delivery of Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE, Washington, DC, between 9 a.m., and 5 p.m.,
Monday through Friday, except Federal holidays.
    [square] Fax: Fax comments to Docket Operations at<PHONE_NUMBER>.
    Privacy: The FAA will post all comments it receives, without
change, to http://regulations.gov, including any personal information
the commenter provides. Using the search function of the docket
website, anyone can find and read the electronic form of all comments
received into any FAA docket, including the name of the individual
sending the comment (or signing the comment for an association,
business, labor union, etc.). DOT's complete Privacy Act Statement can
be found in the Federal Register published on April 11, 2000 (65 FR
19477-19478), as well as at http://DocketsInfo.dot.gov.
    Docket: Background documents or comments received may be read at
http://www.regulations.gov at any time. Follow the online instructions
for accessing the docket or go to the Docket Operations in Room W12-140
of the West Building Ground Floor at 1200 New Jersey Avenue SE,
Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday,
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Jeff Pretz, AIR-691, Small Airplane
Standards Branch, Policy & Innovation Division, Aircraft Certification
Service, Federal Aviation Administration, 901 Locust, Room 301, Kansas
City, MO 64106; telephone<PHONE_NUMBER>; facsimile<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Reason for No Prior Notice and Comment Before Adoption

    The FAA has determined, in accordance with 5 U.S. Code 553(b)(3)(B)
and 553(d)(3), that notice and opportunity for prior public comment
hereon are unnecessary because substantially identical special
conditions have been subject to the public comment process in several
prior instances such that the FAA is satisfied that new comments are
unlikely. For the same reason, the FAA finds that good cause exists for
making these special conditions effective upon issuance. The FAA is
requesting comments to allow interested persons to submit views that
may not have been submitted in response to the prior opportunities for
comment.

------------------------------------------------------------------------
  Special condition No. \2\              Company/airplane model
------------------------------------------------------------------------
23-169-SC....................  Diamond Aircraft Industries GmbH/DA 42,
                                DA 42 NG, DA 42 M-NG, and DA62.
23-185-SC....................  Piper/PA28-236.
23-188-SC....................  Piper/PA28-161.
23-259-SC....................  Cessna Aircraft Company/J183T.
------------------------------------------------------------------------

Comments Invited

    The FAA invites interested people to take part in this rulemaking
by sending written comments, data, or views. The most helpful comments
reference a specific portion of the special conditions, explain the
reason for any recommended change, and include supporting data.
---------------------------------------------------------------------------

    \2\ See http://rgl.faa.gov/ to review the listed special
conditions.
---------------------------------------------------------------------------

    The FAA will consider all comments received on or before the
closing date for comments. The FAA will consider comments filed late if
it is possible to do so without incurring expense or delay. The FAA may
change these special conditions based on the comments received.

Background

    On November 16, 2018, Diamond Aircraft Industries of Canada (DAI-
Canada) applied for FAA validation for a new type certificate for its
Model DA-62 airplane. The Model DA-62 is a normal category, composite,
6 place (excluding pilots seats), twin-engine airplane with retractable
gear, cantilevered low-wing and T-tail monoplane, and a maximum takeoff
weight of 4,407 pounds. The airplane is powered by two Austro Engine
GmbH E4P aircraft diesel engines (E4P), which are type certificated in
the United States (TC No. E00081EN).
    The DAI-Canada Model DA-62 is the same design as the Diamond
Aircraft Industries GmbH Model DA62, a normal category airplane type
certificated under the airworthiness standards listed in Type
Certificate Data Sheet (TCDS) No. A57CE. The FAA issued special
conditions to the Diamond Aircraft Industries GmbH Model DA-42 (Special
Condition No. 23-169-SC) under TCDS No. A57CE \3\ and later applied
them to the Model DA-62, a derivative model that was added to the TCDS
later. DAI-Canada plans to produce the Model DA-62 under a new type
certificate (TC A00012NY); therefore, the FAA is issuing the same
special conditions for the DAI-Canada Model DA-62.
---------------------------------------------------------------------------

    \3\ http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/A4F565159645862583EE00756A7D?OpenDocument.
---------------------------------------------------------------------------

    Expecting the reintroduction of diesel engine technology into the
small airplane fleet, the FAA issued Policy Statement PS-ACE100-2002-
004, Final Policy Statement; Diesel Engine Installation, on May 15,
2004,\4\ which identified areas of technological concern introduction
of new technology diesel engines into small airplanes.
---------------------------------------------------------------------------

    \4\ See http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgPolicy.nsf/0/CD377FA81E29D93A86256D440059EC2F?OpenDocument.
---------------------------------------------------------------------------

    The general areas of concern involved the power characteristics of
the diesel engines, the use of turbine fuel in an airplane class that
has typically been powered by gasoline-fueled engines, and the
vibration characteristics and failure modes of diesel engines. These
concerns were identified after a review of the record of diesel engine
use in airplanes and a review of the part 23 regulations, which
identified specific regulatory areas that needed to be evaluated for
applicability to aircraft diesel engine installations. These concerns
are not considered universally applicable to all types of aircraft
diesel engines and diesel engine installations. However, after review
of the DAI Canada installation, the E4P engine type and the E4P
requirements, and after applying the guidance in PS-ACE100-2002-004,
the FAA has determined the fuel system and engine related special
conditions previously issued in Special Condition No. 23-169-SC on
Diamond Aircraft Industries GmbH Models DA 42, DA 42 NG, DA 42 M-NG,
and DA62

airplanes are necessary for the DAI-Canada Model DA-62 airplane.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, DAI-Canada must show that the
Model DA-62 meets the applicable provisions of 14 CFR part 23, as
amended by amendments 23-1 through 23-62 thereto.
    If the Administrator finds that the applicable airworthiness
regulations in part 23 do not contain adequate or appropriate safety
standards for the Model DA-62 airplane because of a novel or unusual
design feature, special conditions are prescribed under the provisions
of Sec.  21.16.
    The FAA issues special conditions, as defined in Sec.  11.19, under
Sec.  11.38 and they become part of the type certification basis under
Sec.  21.17(a)(2).
    Special conditions are initially applicable to the model for which
they are issued. Should the type certificate for that model be amended
later to include any other model that incorporates the same novel or
unusual design feature, or should any other model already included on
the same type certificate be modified to incorporate the same novel or
unusual design feature, the FAA would apply these special conditions to
the other model.
    In addition to the applicable airworthiness regulations and special
conditions, the Model DA-62 must comply with the fuel vent and exhaust
emission requirements of 14 CFR part 34 and the noise certification
requirements of 14 CFR part 36; and the FAA must issue a finding of
regulatory adequacy under section 611 of Public Law 92-574, the ``Noise
Control Act of 1972.''

Novel or Unusual Design Features

    The Model DA-62 will incorporate the following novel or unusual
design feature: Installation of aircraft diesel engines that use
turbine (jet) fuel.

Discussion

    The major concerns with diesel engine installations identified by
the FAA include installing the diesel engine and noting its vibration
levels under both normal operating conditions and when one cylinder is
inoperative. The concerns also include accommodating turbine fuels in
airplane systems that have generally evolved based on gasoline
requirements, anticipated use of a FADEC to control the engine, and
appropriate limitations and indications for a diesel engine powered
airplane. The general concerns associated with the aircraft diesel
engine installation are as follows:

 Installation and Vibration Requirements
 Fuel and Fuel System Related Requirements
 Full Authority Digital Engine Control (FADEC) and Electrical
System Requirements
 Limitations and Indications

    Installation and Vibration Requirements: These special conditions
include requirements similar to the requirements of Sec.  23.901(d)(1)
for turbine engines. In addition to the requirements of Sec.  23.901
applied to reciprocating engines, the applicant will be required to
construct and arrange each diesel engine installation to result in
vibration characteristics that do not exceed those established during
the type certification of the engine. These vibration levels must not
exceed vibration characteristics that a previously certificated
airframe structure has been approved for, unless such vibration
characteristics are shown to have no effect on safety or continued
airworthiness. The engine limit torque design requirements as specified
in Sec.  23.361 are also modified.
    An additional requirement to consider vibration levels and/or
effects of an inoperative cylinder was imposed. Also, a requirement to
evaluate the engine design for the possibility of, or effect of,
liberating high-energy engine fragments, in the event of a catastrophic
engine failure was added.
    Fuel and Fuel System Related Requirements: Due to the use of
turbine fuel, this airplane must comply with the requirements in Sec.
23.951(c).
    Section 23.961 will be complied with using the turbine fuel
requirements. These requirements will be substantiated by flight-
testing as described in Advisory Circular AC 23-8C, Flight Test Guide
for Certification of Part 23 Airplanes.
    This special condition specifically requires testing to show
compliance with Sec.  23.961 and adds the possibility of testing non-
aviation diesel fuels.
    To ensure fuel system compatibility and reduce the possibility of
misfueling, and discounting the first clause of Sec.  23.973(f)
referring to turbine engines, the applicant will comply with Sec.
23.973(f).
    Due to the use of turbine fuel, the applicant will comply with
Sec.  23.977(a)(2), and Sec.  23.977(a)(1) will not apply. ``Turbine
engines'' will be interpreted to mean ``aircraft diesel engines'' for
this requirement. An additional requirement to consider the possibility
of fuel freezing was imposed.
    Due to the use of turbine fuel, the applicant will comply with
Sec.  23.1305(c)(8).
    Due to the use of turbine fuel, the applicant must comply with
Sec.  23.1557(c)(1)(ii). Section 23.1557(c)(1)(ii) will not apply.
``Turbine engine'' is interpreted to mean ``aircraft diesel engine''
for this requirement.
    FADEC and Electrical System Requirements: The electrical system
must comply with the following:

     In case of failure of one power supply of the electrical
system, there will be no significant engine power change. The
electrical power supply to the FADEC must remain stable in such a
failure.
     The transition from the actual engine electrical network
(FADEC) to the remaining electrical system with the consumer's,
avionics, communication, etc., should be made by a single point only.
If several transitions (e.g., for redundancy reasons) are needed, then
the number of the transitions must be kept as small as possible.
     There must be the ability to separate the FADEC power
supply (alternator) from the battery and from the remaining electrical
system.
     In case of loss of alternator power, the installation must
guarantee that the battery will provide the power for an appropriate
time after appropriate warning to the pilot.
     FADEC, alternator, and battery must be interconnected in
an appropriate way so, in case of loss of battery power, the supply of
the FADEC is guaranteed by the alternator.

Limitations and Indications

    Section 23.1305(a) and (b)(2) will apply, except that propeller
revolutions per minute (RPM) will be displayed. Section 23.1305(b)(4),
(5), and (7) are deleted.
    Additional critical engine parameters for this installation that
will be displayed include--
    (1) Power setting, in percentage (in place of manifold pressure);
and
    (2) Fuel temperature.
    Due to the use of turbine fuel, the requirements for Sec.
23.1521(d), as applicable to fuel designation for turbine engines, will
apply.

Applicability

    As discussed above, these special conditions are applicable to the
DAI-Canada Model DA-62. Should DAI-Canada apply at a later date for a
change to the type certificate to include another model incorporating
the same novel or unusual design feature, the FAA would

apply these special conditions to that model as well.

Conclusion

    This action affects only certain novel or unusual design features
on the Model DA-62 airplane. It is not a rule of general applicability
and it affects only the applicant who applied to the FAA for approval
of these features on the airplane.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

    The authority citation for these special conditions is as follows:

    Authority:  49 U.S.C. 106(f), 106(g), 40113, 44701-44702, 44704,
Pub. L. 113-53, 127 Stat. 584 (49 U.S.C. 44704) note.

The Special Conditions

    Accordingly, pursuant to the authority delegated to me by the
Administrator, the following special conditions are issued as part of
the type certification basis for Diamond Aircraft Industries of Canada
Model DA-62 airplanes.
    1. Engine torque (Provisions similar to Sec.  23.361, paragraphs
(b)(1) and (c)(3)):
    a. For diesel engine installations, the engine mounts and
supporting structure must be designed to withstand the following:
    (1) A limit engine torque load imposed by sudden engine stoppage
due to malfunction or structural failure.
    (a) The effects of sudden engine stoppage may alternatively be
mitigated to an acceptable level by utilization of isolators, dampers
clutches, and similar provisions, so unacceptable load levels are not
imposed on the previously certificated structure.
    b. The limit engine torque to be considered under Sec.  23.361(a)
must be obtained by multiplying the mean torque by a factor of four for
diesel cycle engines.
    (1) If a factor of less than four is used, it must be shown that
the limit torque imposed on the engine mount is consistent with the
provisions of Sec.  23.361(c). In other words, it must be shown that
the use of the factors listed in Sec.  23.361(c)(3) will result in
limit torques on the mount that are equivalent to or less than those
imposed by a conventional gasoline reciprocating engine.
    2. Powerplant--Installation (Provisions similar to Sec.
23.901(d)(1) for turbine engines):
    Considering the vibration characteristics of diesel engines, the
applicant must comply with the following:
    a. Each diesel engine installation must be constructed and arranged
to result in vibration characteristics that--
    (1) Do not exceed those established during the type certification
of the engine; and
    (2) Do not exceed vibration characteristics that a previously
certificated airframe structure has been approved for--
    (i) Unless such vibration characteristics are shown to have no
effect on safety or continued airworthiness, or
    (ii) Unless mitigated to an acceptable level by utilization of
isolators, dampers clutches, and similar provisions, so that
unacceptable vibration levels are not imposed on the previously
certificated structure.
    3. Powerplant--Fuel System--Fuel system with water saturated fuel
(Compliance with Sec.  23.951 requirements):
    Considering the fuel types used by diesel engines, the applicant
must comply with the following:
    a. Each fuel system for a diesel engine must be capable of
sustained operation throughout its flow and pressure range with fuel
initially saturated with water at 80 [deg]F and having 0.75cc of free
water per gallon added and cooled to the most critical condition for
icing likely to be encountered in operation.
    b. Methods of compliance that are acceptable for turbine engine
fuel systems requirements of Sec.  23.951(c) are also considered
acceptable for this requirement.
    4. Powerplant--Fuel System--Fuel system hot weather operation
(Compliance with Sec.  23.961 requirements):
    In place of compliance with Sec.  23.961, the applicant must comply
with the following:
    a. Each fuel system must be free from vapor lock when using fuel at
its critical temperature, with respect to vapor formation, when
operating the airplane in all critical operating and environmental
conditions for which approval is requested. For turbine fuel, or for
aircraft equipped with diesel cycle engines that use turbine or diesel
type fuels, the initial temperature must be 110 [deg]F, -0[deg],
+5[deg], or the maximum outside air temperature for which approval is
requested, whichever is the most critical.
    b. The fuel system must be in an operational configuration that
will yield the most adverse, that is, conservative results.
    c. To comply with this requirement, the applicant must use the
turbine fuel requirements and must substantiate these by flight-
testing, as described in Advisory Circular AC 23-8C, Flight Test Guide
for Certification of Part 23 Airplanes.
    5. Powerplant--Fuel system--Fuel tank filler connection (Compliance
with Sec.  23.973(f) requirements):
    In place of compliance with Sec.  23.973(e) and (f), the applicant
must comply with the following:
    For airplanes that operate on turbine or diesel type fuels, the
inside diameter of the fuel filler opening must be no smaller than 2.95
inches.
    6. Powerplant--Fuel system--Fuel tank outlet (Compliance with Sec.
23.977 requirements):
    In place of compliance with Sec.  23.977(a)(1) and (2), the
applicant will comply with the following:
    There must be a fuel strainer for the fuel tank outlet or for the
booster pump. This strainer must, for diesel engine powered airplanes,
prevent the passage of any object that could restrict fuel flow or
damage any fuel system component.
    7. Powerplant--Powerplant Controls and Accessories--Engine ignition
systems (Compliance with Sec.  23.1165 requirements):
    Considering that the FADEC provides the same function as an
ignition system for this diesel engine, in place of compliance with
Sec.  23.1165, the applicant will comply with the following:
    a. The electrical system must comply with the following
requirements:
    (1) In case of failure of one power supply of the electrical
system, there will be no significant engine power change. The
electrical power supply to the FADEC must remain stable in such a
failure.
    (2) The transition from the actual engine electrical network (FADEC
network) to the remaining electrical system should be made at a single
point only. If several transitions (for example, redundancy reasons)
are needed, then the number of the transitions must be kept as small as
possible.
    (3) There must be the ability to separate the FADEC power supply
(alternator) from the battery and from the remaining electrical system.
    (4) In case of loss of alternator power, the installation must
guarantee the battery will provide the power for an appropriate time
after appropriate warning to the pilot. This period must be at least 30
minutes required, 60 minutes desired.
    (5) FADEC, alternator, and battery must be interconnected in an
appropriate way so, in case of loss of battery power, the supply of the
FADEC is guaranteed by the alternator.

    8. Equipment--General--Powerplant Instruments (Compliance with
Sec.  23.1305 requirements):
    a. In place of compliance with Sec.  23.1305, the applicant will
comply with the following:
    (1) The following are required powerplant instruments:
    (a) A fuel quantity indicator for each fuel tank, installed in
accordance with Sec.  23.1337(b).
    (b) An oil pressure indicator.
    (c) An oil temperature indicator.
    (d) A tachometer indicating propeller speed.
    (e) A coolant temperature indicator.
    (f) An indicating means for the fuel strainer or filter required by
Sec.  23.997 to indicate the occurrence of contamination of the
strainer or filter before it reaches the capacity established in
accordance with Sec.  23.997(d).
    1. No indicator is required if the engine can operate normally for
a specified period with the fuel strainer exposed to the maximum fuel
contamination as specified in MIL-5007D and provisions for replacing
the fuel filter at this specified period (or a shorter period) are
included in the maintenance schedule for the engine installation.
    (g) Power setting, in percentage.
    (h) Fuel temperature.
    (i) Fuel flow (engine fuel consumption).
    9. Operating Limitations and Information--Powerplant limitations--
Fuel grade or designation (Compliance with Sec.  23.1521(d)
requirements):
    Instead of compliance with Sec.  23.1521(d), the applicant must
comply with the following:
    The minimum fuel designation (for diesel engines) must be
established so it is not less than that required for the operation of
the engines within the limitations in paragraphs (b) and (c) of Sec.
23.1521.
    10. Markings and Placards--Miscellaneous markings and placards--
Fuel, oil, and coolant filler openings (Compliance with Sec.
23.1557(c)(1) requirements):
    Instead of compliance with Sec.  23.1557(c)(1), the applicant must
comply with the following:
    a. Fuel filler openings must be marked at or near the filler cover
with--
    (1) For diesel engine-powered airplanes--
    (a) The words ``Jet Fuel''; and
    (b) The permissible fuel designations, or references to the
Airplane Flight Manual (AFM) for permissible fuel designations.
    (c) A warning placard or note that states the following or similar:
    ``Warning--this airplane equipped with an aircraft diesel engine,
service with approved fuels only.''
    The colors of this warning placard should be black and white.
    11. Powerplant--Fuel system--Fuel-freezing:
    If the fuel in the tanks cannot be shown to flow suitably under all
possible temperature conditions, then fuel temperature limitations are
required. These will be considered as part of the essential operating
parameters for the aircraft and must be limitations.
    a. The takeoff temperature limitation must be determined by testing
or analysis to define the minimum cold-soaked temperature of the fuel
that the airplane can operate on.
    b. The minimum operating temperature limitation must be determined
by testing to define the minimum operating temperature acceptable after
takeoff (with minimum takeoff temperature established in (a) of this
paragraph).
    12. Powerplant Installation--Vibration levels:
    a. Vibration levels throughout the engine operating range must be
evaluated and:
    (1) Vibration levels imposed on the airframe must be less than or
equivalent to those of the gasoline engine; or
    (2) Any vibration level that is higher than that imposed on the
airframe by the replaced gasoline engine must be considered in the
modification and the effects on the technical areas covered by the
following paragraphs must be investigated: 14 CFR part 23, Sec. Sec.
23.251; 23.613; 23.627; 23.629 (or CAR 3.159, as applicable to various
models); 23.572; 23.573; 23.574 and 23.901.
    b. Vibration levels imposed on the airframe can be mitigated to an
acceptable level by use of isolators, dampers clutches, and similar
provisions, so unacceptable vibration levels are not imposed on the
previously certificated structure.
    13. Powerplant Installation--One cylinder inoperative:
    It must be shown by test or analysis, or by a combination of
methods, that the airframe can withstand the shaking or vibratory
forces imposed by the engine if a cylinder becomes inoperative. Diesel
engines of conventional design typically have extremely high levels of
vibration when a cylinder becomes inoperative. Data must be provided to
the airframe installer/modifier so either appropriate design
considerations or operating procedures, or both, can be developed to
prevent airframe and propeller damage.
    14. Powerplant Installation--High Energy Engine Fragments:
    It may be possible for diesel engine cylinders (or portions
thereof) to fail and physically separate from the engine at high
velocity (due to the high internal pressures). This failure mode will
be considered possible in engine designs with removable cylinders or
other non-integral block designs. The following is required:
    a. It must be shown that the engine construction type (massive or
integral block with non-removable cylinders) is inherently resistant to
liberating high energy fragments in the event of a catastrophic engine
failure; or,
    b. It must be shown by the design of the engine, that engine
cylinders, other engine components or portions thereof (fragments)
cannot be shed or blown off the engine in the event of a catastrophic
engine failure; or
    c. It must be shown that all possible liberated engine parts or
components do not have adequate energy to penetrate engine cowlings; or
    d. Assuming infinite fragment energy, and analyzing the trajectory
of the probable fragments and components, any hazard due to liberated
engine parts or components will be minimized and the possibility of
crew injury is eliminated. Minimization must be considered during
initial design and not presented as an analysis after design
completion.

    Issued in Kansas City, Missouri, on October 3, 2019.
William Schinstock,
Acting Manager, Small Airplane Standards Branch, Policy and Innovation
Division, Aircraft Certification Service.
[FR Doc. 2019-22118 Filed 10-9-19; 8:45 am]
 BILLING CODE 4910-13-P