[Federal Register Volume 89, Number 211 (Thursday, October 31, 2024)]
[Rules and Regulations]
[Pages 86713-86717]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-25238]
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Rules and Regulations
Federal Register
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This section of the FEDERAL REGISTER contains regulatory documents
having general applicability and legal effect, most of which are keyed
to and codified in the Code of Federal Regulations, which is published
under 50 titles pursuant to 44 U.S.C. 1510.
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Federal Register / Vol. 89, No. 211 / Thursday, October 31, 2024 /
Rules and Regulations
[[Page 86713]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 21
[Docket No. FAA-2022-1726]
Airworthiness Criteria: Special Class Airworthiness Criteria for
the AgustaWestland Philadelphia Corporation Model AW609 Powered-Lift
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Issuance of final airworthiness criteria.
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SUMMARY: The FAA announces the special class airworthiness criteria for
the AgustaWestland Philadelphia Corporation (AWPC) Model AW609 powered-
lift. This document sets forth the airworthiness criteria the FAA finds
to be appropriate and applicable for the powered-lift design.
DATES: These airworthiness criteria are effective December 2, 2024.
FOR FURTHER INFORMATION CONTACT: Richard C Snyder, Certification
Coordination Section, AIR-613, Policy and Standards Division, Aircraft
Certification Service, 10101 Hillwood Parkway, Fort Worth, TX 76177;
telephone and fax 817-222-4486; email [email protected].
SUPPLEMENTARY INFORMATION:
Background
The AWPC Model AW609 is a two-engine powered-lift with a maximum
weight of 17,500 lbs., and a capacity of two crew and nine passengers.
The aircraft has two ``proprotors'' instead of propellers or rotors.
The AW609 design is a direct descendant of the Bell Helicopter Model
BA609 certification project, which had design origins from the
experimental Bell XV-15 aircraft.
The FAA issued a notice of proposed airworthiness criteria for the
AW609 powered-lift, which published in the Federal Register on June 9,
2023 (88 FR 37805).
After several changes of applicants, on February 15, 2012,
AgustaWestland Tilt-Rotor Company, now AWPC, applied for a type
certificate for the Model AW609. Under 14 CFR 21.17(c), an application
for type certification is effective for three years, unless the FAA
approves a longer period. Section 21.17(d) provides that, where a type
certificate has not been issued within the time limit established under
Sec. 21.17(c), the applicant may file for an extension and update the
designated applicable regulations in the type certification basis.
Since the project was not certificated within the established time
limit, the FAA approved a series of requests for extension by AWPC with
the most recent request submitted on February 22, 2024. If the
application extension is approved, the date of the updated type
certification basis will change from March 31, 2021, to March 31, 2024.
Discussion
Powered-lift are type certificated as special class aircraft
because the FAA has not yet established powered-lift airworthiness
standards as a separate part of subchapter C of 14 CFR. Under the
procedures in Sec. 21.17(b), the airworthiness requirements for
special class aircraft are the portions of the requirements in parts
23, 25, 27, 29, 31, 33, and 35 found by the FAA to be appropriate and
applicable to the specific type design and any other airworthiness
criteria found by the FAA to provide an equivalent level of safety to
the existing standards. These final airworthiness criteria announce the
applicable regulations and other airworthiness criteria developed for
type certification of the Model AW609 powered-lift under Sec.
21.17(b).
The powered-lift has characteristics of both a rotorcraft and an
airplane. It is designed to function as a helicopter for takeoff and
landing, and as an airplane cruising at higher speeds than a helicopter
during the enroute portion of flight operations. Accordingly, the Model
AW609 certification basis contains standards from parts 23, 25, and 29,
as well as other airworthiness criteria specific for a powered-lift.
This certification basis includes parts 23, 25, and 29
airworthiness standards. These are part 23 at amendment 23-62, part 25
at amendment 25-135 (except Sec. 25.903(a) at amendment 25-140 and
Sec. 25.1517 at amendment 25-86), and part 29 at amendment 29-55
(except Sec. 29.1353 at amendment 29-59). The certification basis
incorporates by reference existing transport category airplane and
rotorcraft standards, one normal category airplane standard, Category A
rotorcraft standards, optional Category B rotorcraft standards, and
criteria for operation under instrument flight rules. Flight into known
icing conditions (FIKI) is not being sought with the current
certification; however, FIKI is included in these airworthiness
criteria for future certifications.
The certification basis also includes new criteria unique to the
powered-lift design, designated as tiltrotor (TR) criteria. Many of
these TR criteria consist of modified part 25 or 29 standards. Some
include criteria that combine existing parts 23, 25, and 29 standards,
as the maximum weight of the Model AW609 exceeds the weight for normal
category rotorcraft and most part 23 category airplanes, but its
passenger seating is less than that of a transport category airplane or
a transport category rotorcraft. The FAA also developed TR criteria
because no existing standard captures the powered-lift's transitional
flight modes (during flight, the powered-lift nacelle rotates the
proprotor system from providing vertical lift to horizontal
propulsion). The TR criteria also contain definitions specific for the
powered-lift, such as flight modes, configurations, speeds, and
terminology (``flaperon'' instead of ``aileron'' or ``flap;''
``proprotor'' instead of ``rotor'' or ``propeller'').
For example, while existing parts 25 and 29 standards for passenger
emergency exits include a size classification (types I, II, III, IV)
depending on the passenger seating capacity and other factors, the
certification basis has a TR with criteria for the specific type of
passenger emergency exit that is part of the design of the Model AW609.
Another example involves fatigue evaluation. Part 25 contains
requirements such as a limit of validity (LOV) on airframe fatigue for
pressurized fuselages, which are not in part 29. Instead, fatigue
evaluation in part 29 includes a composite structures fatigue rule, due
to the more extreme fatigue environment of rotorcraft. For small
airplanes, part 23, amendment
[[Page 86714]]
23-48, added a composite airframe evaluation requirement for bonded
joints, which is included in agency compliance guidance for parts 25
and 29 but not required by a specific regulation (the safety
requirement is complied with through other broad existing regulations
in those parts). Since the Model AW609 has a pressurized fuselage, the
FAA developed TR criteria to include the LOV requirement. The
certification basis incorporates by reference the part 29 composite
rotorcraft structures fatigue rule, TR criteria to include the
composite bonding requirements from part 23, as well as TR criteria to
include fatigue requirements for elastomeric primary structural
elements. The new requirements specific to the AWPC Model AW609 in the
proposed airworthiness criteria used a ``TR.xxxx'' section-numbering
scheme.
Summary of Changes From the Proposed Airworthiness Criteria
Based on comments received, these final airworthiness criteria
reflect the following changes, in addition to others as explained in
more detail in the Discussion of Comments section:
Added Sec. 29.1547 to the final airworthiness criteria
for the case where a magnetic compass is installed.
Revised these final airworthiness criteria to provide
clarification on future certification for FIKI conditions.
Clarified statements about TR.45 applicability.
Revised proposed TR.575 to account for the unique nature
and operating environment of elastomeric principle structural elements
(PSEs).
Updated Sec. 25.775 to clarify that the reference to
Sec. 25.335(a) is replaced with TR.335(a) for the purposes of these
airworthiness criteria.
Did not include Sec. 25.875 and updated TR.875 in these
final airworthiness criteria to prevent confusion between the terms
propeller and proprotor, thereby combining proposed TR.875 and Sec.
25.875, which call out requirements for buffeting, proprotor
(propeller), and other rotating components. Accordingly, TR.875 in
these final airworthiness criteria addresses both proposed TR.875 and
Sec. 25.875.
Revised the incorporation by reference of Sec. 29.1521 to
reflect that the reference to Sec. 29.1509(c) is replaced with
TR.1509(c) since Sec. 29.1509 is not part of the type certification
basis for the Model AW609.
Specified the amendment level for Sec. 25.1517 to be 25-
86.
Revised these airworthiness criteria to remove Sec.
25.1353 and include Sec. 29.1353 at amendment 29-59 for electrical
wiring protection due to recent amendments to part 29.
Addition of Position Light TRs
After the FAA issued the notice of proposed airworthiness criteria
for public comment, AWPC presented a forward left and right position
light design that would not meet the prescriptive regulatory
requirements defined under Sec. Sec. 29.1385-29.1395. In general
terms, the existing requirements define the use of a single left and a
single right forward-looking position light. Due to the AW609
configuration, AWPC proposed using multiple light sources for each
forward position light providing lighting at a level comparable to the
part 29 lighting requirements. The FAA developed TR.1385, TR.1387,
TR.1389, TR.1391, TR.1393, and TR.1395 to establish the same level of
safety to Sec. Sec. 29.1385, 29.1387, 29.1389, 29.1391, 29.1393, and
Sec. 29.1395 to address the non-traditional configuration of the AW609
powered-lift's position lights. These TRs modified the language in
certain part 29 sections to allow for a group of forward position
lights to be installed on each side of the aircraft.
Discussion of Comments
The FAA received responses from six commenters including: Overair,
Inc (Overair), Parker Lord Corporation (Parker Lord), Advanced Air
Mobility Institute, Transport Canada, and two individual commenters.
Subpart A--General
The FAA proposed criteria that adopted existing and developed
definitions and abbreviations specifically for the Model AW609 powered-
lift under subpart A. The FAA received and reviewed comments from
Transport Canada and Overair regarding subpart A of the proposed
airworthiness criteria.
Transport Canada requested the FAA revise TR.10(c) to use the
phrase ``flightdeck'' instead of ``cockpit'' for consistency with
TR.1322. The FAA concurs and has revised TR.10(c) to use the term
``flightdeck.''
Transport Canada requested the FAA revise TR.11 by adding a
statement that abbreviations in these criteria apply in addition to the
abbreviations in 14 CFR 1.2. The FAA does not agree with Transport
Canada's request because 14 CFR part 1.2 abbreviations are applicable
unless specifically addressed as not being applicable in the
certification basis.
Overair stated that ``VMIN'' as defined in TR.11(c) and
``minimum safe speed'' as defined in other previously issued powered-
lift special class airworthiness criteria would cause confusion between
the two terms. The FAA disagrees with Overair. The airworthiness
criteria for the AW609 are a special class certification basis and as
such, the requirements are specific for this aircraft rather than
generally applicable. In addition, the development of the AW609
certification basis predates the use of performance-based rules, which
is the approach generally used for other special class powered-lift or
similar aircraft.
Subpart B--Flight
The FAA proposed criteria that adopted existing regulations from
subpart B of parts 23, 25, and 29, as well as developed criteria
specifically for the Model AW609 powered-lift . Subpart B covers a wide
range of flight criteria including performance, controllability, trim,
stability, and stalls.
The FAA received and reviewed comments from Overair regarding
subpart B of the proposed airworthiness criteria.
Overair requested the FAA clarify the safety intent of TR.45
related to the hovering ceiling given the differences in airworthiness
criteria proposed for different powered-lift types. The FAA
acknowledges Overair's request. TR.45 is general performance for
Category A aircraft. The FAA developed these airworthiness criteria for
the AW609 for guaranteed performance that would integrate all aircraft
flight modes defined in TR.10 and HTR.45 including hover. TR Appendix
H--Category B Performance defines Category B performance and HTR.45
addresses general performance determination.
Overair requested the FAA justify the climb performance identified
in TR.67. Specifically, Overair requested the FAA explain why Sec.
29.67(a)(1) was not adopted for the first takeoff segment and explain
the rationale for adopting part 25 fixed-wing OEI minimum climb
gradient criteria for this powered-lift special class aircraft.
Finally, Overair inquired whether these performance requirements will
provide the same level of safety when operating out of heliports and/or
vertiports.
The FAA acknowledges Overair's comment. The FAA determined Sec.
29.67(a)(1), which establishes climb performance at 200 ft, was
inappropriate for a transport category powered-lift such as the AW609.
In addition, the FAA did not adopt part 25 fixed-wing OEI climb
requirements for the AW609. Rather, the FAA established different
takeoff flight paths for ground-level heliports under TR.59 and
elevated heliports under TR.60 that do not exist
[[Page 86715]]
under part 25. The takeoff flight path under TR.59 and TR.69 utilizes
the performance established under TR.67 to ensure positive engine out
climb performance from the surface to 1500 ft above ground level, for
different segments.
Overair requested the FAA clarify why a stall speed has been
adopted for the AW609 as opposed to the ``minimum safe speed'' in other
powered-lift special class airworthiness criteria. The FAA acknowledges
Overair's comment. The AW609 is a Sec. 21.17(b) special class
certification basis aircraft and the airworthiness criteria are
specific to this aircraft. Unlike other Sec. 21.17(b) powered-lift,
the AW609 certification basis did not use performance-based criteria.
There are differences between performance-based and prescriptive
criteria. Conversion-mode minimum safe speed is covered elsewhere in
the AW609 airworthiness criteria; in the AW609 airworthiness criteria,
airplane-mode (wing-borne) minimum safe speed is covered in TR.103,
201, 203, and 207. Conversion-mode (Semi-thrust borne) minimum safe
speed is covered in TR.38 and 143. While the airworthiness criteria for
the AW609 may be different from the airworthiness criteria for other
powered-lift, the safety intent is the same with regards to stall and
minimum speeds.
Overair requested the FAA explain why the wind velocity
requirement, from all azimuths, has been increased from ``at least 17
knots'' in Sec. 29.143(c) to 20 knots. The FAA acknowledges Overair's
comment. The AW609, as a special class aircraft, is a transport
category aircraft and its certification basis includes appropriate
requirements from both parts 25 and 29. Section 25.237(a)(1) requires
``a 90-degree cross component of wind velocity, demonstrated to be safe
for takeoff and landing, . . . [that] must be at least 20 knots . . .''
The FAA determined that Sec. 29.143(c) and (d)'s requirements of at
least 17 knots all azimuth capability could provide a controllability
gap for the AW609 when attempting to land or takeoff; as such the FAA
adopted 20 knots to maintain consistency with transport aircraft
requirements for specific applicability to the AW609. This approach is
consistent with the draft ``Interim Airworthiness Criteria for Powered-
Lift Transport Category Aircraft,'' dated July 1988.
The FAA received several comments from Overair on the topics of
flight performance and characteristics, and Overair requested an
explanation as to why the FAA adopted older, non-performance-based
criteria. The FAA establishes the minimum safety standards without
dictating designs. Manufacturers are free to choose the design strategy
that suits their powered-lift, as long as these designs meet a minimum
accepted safety standard.
The FAA received multiple comments from Overair regarding the
stability criteria proposed in TR.173 (static longitudinal stability),
TR.175 (demonstration of static longitudinal stability), and TR.177
(static lateral-directional stability). Overair asked for clarification
as to why proposed TR.173, TR.175, and TR.177 include stability
requirements from the 1960's instead of using recent special conditions
for part 25 aircraft equipped with a full-authority electronic flight
control system. Overair requested the FAA incorporate more current
airworthiness standards for fly-by-wire technology into the AW609
certification basis. The FAA does not concur with Overair's request to
revise TR.173, TR.175, and TR.177 to incorporate recent special
conditions for fly-by-wire technology. The recent fly-by-wire special
conditions were considered in TR.173, TR.175, and TR.177. The
commenter's assumption, that the recent special conditions were not
considered for the TRs, is incorrect.
Overair also inquired as to why proposed TR.181(a)(1) and
TR.181(a)(2) (free and fixed position dynamic stability criteria,
respectively) were included in the airworthiness criteria for an
aircraft equipped with an irreversible electronic flight control
system. Overair requested the FAA not adopt proposed TR.181(a)(1) and
TR.181(a)(2) in the final airworthiness criteria. The FAA does not
concur with Overair's request to not adopt proposed TR.181(a)(1) and
TR.181(a)(2) in the final airworthiness criteria. The FAA determined
that evaluation of free and fixed flight control characteristics is
necessary even if an aircraft has an irreversible electronic flight
control system.
Subpart C--Structure and Strength
The FAA proposed criteria that adopted existing regulations from
subpart C of parts 25 and 29, as well as developed criteria
specifically for the AW609. Subpart C covers a wide range of strength
criteria including flight loads, control surface loads, emergency
landing conditions, and fatigue evaluations. The FAA received and
reviewed comments from Parker Lord and one individual commenter.
Parker Lord requested the FAA revise the definition of a Primary
Structural Element (PSE). Parker Lord also recommended the FAA change
the qualification and certification of elastomeric PSEs from physical
and static strength attributes to material functionality and the
dynamic response within the design requirements of the rotor system.
The FAA agrees with Parker Lord's requests and has revised the language
in final TR.575 to use the designed dynamic response of the material as
compliance criteria instead of traditional static loading, deformation,
and fatigue for compliance criteria.
An individual commenter suggested the AW609 may become unstable in
a windmilling condition and may develop whirl flutter. The commenter
stated the aircraft should be tested for stability in this situation
and if necessary given procedures and limitations. The commenter also
stated that if the system design prevents windmilling, there should be
backup systems and procedures. FAA acknowledges the commenter's
concern. Windmilling impact on aircraft stability, including any impact
on whirl flutter, is already evaluated under Sec. 25.629 and TR.629,
therefore, no additional changes are deemed necessary to those
airworthiness criteria.
Subpart D--Design and Construction
The FAA proposed criteria that adopted existing regulations from
subpart D of parts 25 and 29, as well as developed criteria
specifically for the Model AW609 powered-lift. Subpart D covers a wide
range of design and construction criteria including criteria covering
rotors, control systems, landing gear, and personnel and cargo
accommodations.
The FAA received and reviewed comments from Overair and Transport
Canada regarding subpart D of the proposed airworthiness criteria.
Transport Canada requested the FAA specify which paragraphs of
Sec. 25.335 and TR.335 the FAA is referring to in the reference to
Sec. 25.775 in the proposed airworthiness criteria. The FAA has
revised the reference to Sec. 25.775 in the final airworthiness
criteria to indicate that Sec. 25.335(a) is replaced with TR.335(a).
Transport Canada requested the FAA add Sec. 25.865 to the final
airworthiness criteria because that regulation addresses fire
protection requirements for the engine mounting structure and engine
attachment points. The FAA does not agree with Transport Canada's
request. Section 29.861(a) is included in the final airworthiness
criteria, and uses the term ``structure,'' which includes engine mounts
as indicated by the example in the guidance material of AC 29.861. As a
result, compliance with Sec. 29.861(a) must also address engine
[[Page 86716]]
mounting structure and engine attachment points. Applying Sec.
29.861(a) is sufficient for this powered-lift, and requiring compliance
to Sec. 25.865 is not necessary. AC 29-2C ``Certification of Transport
Category Rotorcraft'' and AC 29.861 ``Fire Protection of Structure,
Controls, and Other Parts'' provide guidance for engine mounts and fire
protection requirements.
Transport Canada stated that Sec. 25.867 does not define clearly
what surfaces to consider as ``rear of the nacelles'' and requested the
FAA clarify the intent with a figure to define the envelope and
boundaries radially and axially. The FAA does not agree with Transport
Canada's request to provide a figure as this figure is defined in the
project specific methods of compliance to Sec. 25.867.
Transport Canada requested a rationalization of the FAA's exception
of Sec. 25.869(a)(3) from the proposed airworthiness criteria and
requested the FAA include Sec. 25.869(a)(3) in the final airworthiness
criteria. Additionally, the commenter provided wording for Sec.
25.869(a)(3) from amendment 25-113 even though the current amendment is
25-123, which has different language. The FAA does not concur with
Transport Canada's request to include Sec. 25.869(a)(3) at either
amendment level in the final airworthiness criteria as the
airworthiness criteria already contain criteria such as Sec. 29.1301,
TR.1309, and Sec. 29.1353 that are intended to address the same
requirements as those covered by the various part 25 wiring and EWIS
requirements, including Sec. 25.869(a)(3).
Overair commented that the inclusion of both Sec. 25.675(a) and
Sec. 29.675(a) in the proposed airworthiness criteria was confusing
and requested the FAA not make Sec. 25.675(a) applicable to the AW609
because Sec. 29.675(a) is also applicable. The FAA does not concur
with this request. Both regulations need to be included in the final
airworthiness criteria because the AW609 operates in both helicopter
and airplane modes including the conversion mode. The AW609 aircraft
control is affected by rotor collective and cyclic pitch, conventional
airplane control surfaces (elevator, flaperons), and nacelle tilt;
traditional helicopter-type pilot controls in the cockpit provide
aircraft control in pitch, roll, and yaw axes.
Overair requested the FAA not adopt Sec. 25.875 from the proposed
airworthiness criteria and reword TR.875 to prevent confusion. The FAA
concurs with this request and has revised the final airworthiness
criteria to not adopt Sec. 25.875 and reworded TR.875 to reflect the
use of ``proprotors'' instead and of propellers to reflect TR.10(o)
terminology.
Subpart E--Powerplant
The FAA proposed criteria that adopted existing regulations from
subpart E of parts 25 and 29, as well as developed criteria
specifically for the Model AW609 powered-lift. Subpart E covers a wide
range of powerplant criteria including rotor drive systems, fuel
systems, oil systems, and cooling and exhaust systems. The FAA received
and reviewed comments from Transport Canada and one individual
commenter regarding subpart E of the proposed airworthiness criteria.
Transport Canada requested the FAA revise proposed TR.963 to remove
the phrase ``for compliance with'' and replace it with ``in addition
to.'' FAA does not concur with Transport Canada's request. The
requested change would increase the testing requirements for flexible
fuel tank bladders in a way that is not intended.
Transport Canada requested the FAA rationalize the exception of
Sec. 25.1203(h) from the proposed airworthiness criteria and to
include Sec. 25.1203(h) in the final airworthiness criteria. The FAA
does not concur with the request to include Sec. 25.1203(h) in the
final airworthiness criteria as the airworthiness criteria already
contain criteria such as Sec. 29.1301, TR.1309, and Sec. 29.1353 that
are intended to address similar requirements as those covered by the
various part 25 EWIS requirements, including Sec. 25.1203(h).
The FAA received several comments with no specific requested
changes to the proposed airworthiness criteria from an individual on
several aspects regarding FIKI, icing protection, and inadvertent icing
encounters.
The commenter inquired as to whether the AW609 has any relief from
the subpart E powerplant-related requirements of normal FIKI
certification other than having no subpart B testing with ice shapes
and the relief of limited exposure time. The commenter also inquired as
to whether the flight manual limitation that ``the pilot is prohibited
from flight into known or forecast icing'' reduces or eliminates any of
the other subpart E requirements for the AW609 that are normally
included in a FIKI certification. The FAA acknowledges the commenter's
questions: the powerplant icing requirements are applicable per
TR.1093, regardless of the aircraft's FIKI status.
Subpart G--Operating Limitations and Information
The FAA proposed criteria that adopted existing regulations from
subpart G of parts 25 and 29, as well as developed criteria
specifically for the Model AW609 powered-lift. Subpart G covers a wide
range of operating limitations and information criteria including
airspeed, markings and placards, indicators, and flight manuals. The
FAA received and reviewed comments from Transport Canada regarding
subpart G of the proposed airworthiness criteria.
Transport Canada requested the FAA revise the reference to Sec.
25.1585(a)(8) in Sec. 25.1517 to read ``Sec. 25.1585(a)(3)'' and
explained that Sec. 25.1585(a)(8) does not exist.'' The FAA
acknowledges Transport Canada's request; however, the reference to
Sec. 25.1585(a)(8) is correct. The FAA revised the final airworthiness
criteria to indicate that the criteria includes Sec. 25.1517, Rough
air speed, VRA is at amendment 25-86, which contains (a)(8).
Transport Canada requested the FAA revise the reference to Sec.
29.1509 and TR.1509 in Sec. 29.1521 to include the appropriate
paragraphs. The FAA concurs and revised the reference to Sec. 29.1509
and TR.1509 to indicate that paragraph (c) is the appropriate
paragraph.
Transport Canada requested the FAA add ``Sec. 29.1547 Magnetic
direction indicator. (a)-(d) [Applicable to AW609]'' to the
airworthiness criteria and, if the FAA agrees, then also add a
reference to Sec. 29.1547 in TR.1501(b). The FAA concurs with adding
Sec. 29.1547 to these final airworthiness criteria and notes that
Sec. 29.1327 is the requirement for a magnetic compass and Sec.
29.1547 is the requirement for a calibration card if a compass is
installed. In lieu of a magnetic compass, Sec. 25.1303 and TR.1303
allow for direction indicators (gyroscopically stabilized, magnetic or
non-magnetic).
General Comments
The FAA received comments on the proposed criteria that were not
specific to any subpart from The Advanced Air Mobility Institute,
Transport Canada, and one individual commenter.
Transport Canada made several comments concerning the structure and
formatting of the airworthiness criteria document. Transport Canada
further stated that the airworthiness criteria as written references
many requirements instead of writing the actual text for the
airworthiness criteria. Transport Canada suggested the FAA write the
actual text for airworthiness criteria throughout the
[[Page 86717]]
document to make explicit the text agreed to when these airworthiness
criteria are finalized. The FAA disagrees, because the 14 CFR
regulations listed in the airworthiness criteria for the AW609 are
incorporated into the criteria by referencing the existing rule.
Transport Canada stated that the formula in proposed TR.725 Limit
drop test, paragraph (d), is incomplete. The FAA disagrees with
Transport Canada. The formula is correctly stated in the proposed
criteria, and matches the formula suggested by the commenter.
Transport Canada stated the heading for proposed TR.103 Stall SPEED
is incorrect and that the term ``SPEED'' should be lower case and in
bold text. The FAA agrees with Transport Canada and has corrected the
heading in TR.103 in the final airworthiness criteria.
Transport Canada requested the FAA explain why Sec. Sec. 25.1701-
25.1733 for an EWIS were not included in the proposed airworthiness
criteria and requested the FAA add Sec. Sec. 25.1701-25.1733. The FAA
does not concur with Transport Canada's request to include Sec. Sec.
25.170-25.1753 in the final airworthiness criteria as the FAA updated
the final airworthiness criteria to replace Sec. 25.1353 with Sec.
29.1353 due to the recent addition of amendment 29-59 which introduced
a part 29 safety target for electrical wiring. The final airworthiness
criteria also contain Sec. 29.1301, and TR.1309 which, in addition to
Sec. 29.1353, address similar requirements to those covered by the
referenced part 25 EWIS and energy storage requirements.
Transport Canada requested the FAA clarify whether part 34, Fuel
Venting and Exhaust Emission Requirements For Turbine Engine Powered
Airplanes, is applicable to the AW609, either to the engine or
aircraft, as fuel venting can be influenced by the engine's
installation effects. The FAA acknowledges Transport Canada's concern.
The AW609 uses the PT6C-67A, which is a turboshaft engine. Part 34 does
not apply to turboshaft engines. As long as the AW609 continues to use
a turboshaft engine, part 34 will not be applicable.
Transport Canada requested the FAA clarify whether part 38,
Airplane Fuel Efficiency Certification is applicable to the AW609. The
AW609 certification basis precedes the promulgation of 14 CFR part 38,
and thus part 38 is not applicable to the AW609.
The Advanced Air Mobility Institute recommended the FAA update and
expand the airworthiness criteria for the Model AW609 powered-lift to
require the implementation of a mandatory safety management system
(SMS), designated as TR criteria. The FAA does acknowledge the value of
implementation of a proactive SMS system. However, implementation of
SMS is beyond the scope of this present effort to designate the
applicable airworthiness criteria for this powered-lift.
Applicability
These airworthiness criteria, established under the provisions of
Sec. 21.17(b), are applicable to the AWPC Model AW609 powered-lift.
Should AWPC apply at a later date for a change to the type certificate
to include another model, these airworthiness criteria would apply to
that model as well, provided the FAA finds them appropriate in
accordance with the requirements of subpart D to part 21.
Conclusion
This action affects only certain airworthiness criteria for the
AWPC Model AW609 powered-lift. It is not a standard of general
applicability.
Authority Citation
The authority citation for these airworthiness criteria is as
follows:
Authority: 49 U.S.C. 106(g), 40113, and 44701-44702, 44704.
Airworthiness Criteria
Pursuant to the authority delegated to me by the Administrator, the
following airworthiness criteria are issued as part of the type
certification basis for the AgustaWestland Philadelphia Corporation
Model AW609 powered-lift. You may view the final airworthiness criteria
on the internet at www.regulations.gov in Docket No. FAA-2022-1726.
Issued in Kansas City, Missouri, on October 25, 2024.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2024-25238 Filed 10-30-24; 8:45 am]
BILLING CODE 4910-13-P