[Federal Register Volume 88, Number 139 (Friday, July 21, 2023)]
[Rules and Regulations]
[Pages 46956-46958]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-15466]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2021-1035; Special Conditions No. 25-819-SC]
Special Conditions: Airbus Model A321neo XLR Airplane; Side-Stick
Controller--Controllability and Maneuverability
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
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SUMMARY: These special conditions are issued for the Airbus Model
A321neo XLR airplanes. The airplane will have a novel or unusual design
feature when compared to the state of technology envisioned in the
airworthiness standards for transport-category airplanes. This design
feature is side-stick controllers for pitch and roll control. The
applicable airworthiness regulations do not contain adequate or
appropriate safety standards for this design feature. These special
conditions contain the additional safety standards that the
Administrator considers necessary to establish a level of safety
equivalent to that established by the existing airworthiness standards.
[[Page 46957]]
DATES: This action is effective on Airbus on July 21, 2023. Send
comments on or before September 5, 2023.
ADDRESSES: Send comments identified by Docket No. FAA-2021-1035 using
any of the following methods:
Federal eRegulations Portal: Go to https://www.regulations.gov/ and follow the online instructions for sending
your comments electronically.
Mail: Send comments to Docket Operations, M-30, U.S.
Department of Transportation (DOT), 1200 New Jersey Avenue SE, Room
W12-140, West Building Ground Floor, Washington, DC 20590-0001.
Hand Delivery or Courier: Take comments to Docket
Operations in Room W12-140 of the West Building Ground Floor at 1200
New Jersey Avenue SE, Washington, DC, between 9 a.m. and 5 p.m., Monday
through Friday, except Federal holidays.
Fax: Fax comments to Docket Operations at 202-493-2251.
Privacy: Except for Confidential Business Information (CBI) as
described in the following paragraph, and other information as
described in title 14, Code of Federal Regulations (14 CFR) 11.35, the
FAA will post all comments received without change to https://www.regulations.gov/, including any personal information you provide.
The FAA will also post a report summarizing each substantive verbal
contact received about these special conditions.
Confidential Business Information: Confidential Business
Information (CBI) is commercial or financial information that is both
customarily and actually treated as private by its owner. Under the
Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from
public disclosure. If your comments responsive to these special
conditions contain commercial or financial information that is
customarily treated as private, that you actually treat as private, and
that is relevant or responsive to these special conditions, it is
important that you clearly designate the submitted comments as CBI.
Please mark each page of your submission containing CBI as ``PROPIN.''
The FAA will treat such marked submissions as confidential under the
FOIA, and the indicated comments will not be placed in the public
docket of these special conditions. Send submissions containing CBI to
Troy Brown, Performance and Environment Unit, AIR-621A, Technical
Policy Branch, Policy and Standards Division, Aircraft Certification
Service, Federal Aviation Administration, 1801 S Airport Rd., Wichita,
KS 67209-2190; telephone and fax 405-666-1050; email
[email protected]. Comments the FAA receives, which are not
specifically designated as CBI, will be placed in the public docket for
these special conditions.
Docket: Background documents or comments received may be read at
https://www.regulations.gov/ at any time. 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: Troy Brown, Performance and
Environment Unit, AIR-621A, Technical Policy Branch, Policy and
Standards Division, Aircraft Certification Service, Federal Aviation
Administration, 1801 S Airport Rd., Wichita, KS 67209-2190; telephone
and fax 405-666-1050; email [email protected].
SUPPLEMENTARY INFORMATION: The substance of these special conditions
has been published in the Federal Register for public comment in
several prior instances with no substantive comments received.
Therefore, the FAA finds, pursuant to Sec. 11.38(b), that new comments
are unlikely, and notice and comment prior to this publication are
unnecessary.
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.
The FAA will consider all comments received by the closing date for
comments. The FAA may change these special conditions based on the
comments received.
Background
On September 16, 2019, Airbus applied for an amendment to Type
Certificate No. A28NM to include the new Model A321neo XLR airplanes,
which include the Model A321-271NY and -253NY airplanes. These
airplanes are twin-engine, transport-category airplanes with seating
for 244 passengers and a maximum takeoff weight of 222,000 pounds.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Airbus must show that the
Model A321neo XLR airplanes meet the applicable provisions of the
regulations listed in Type Certificate No. A28NM, or the applicable
regulations in effect on the date of application for the change, except
for earlier amendments as agreed upon by the FAA.
If the Administrator finds that the applicable airworthiness
regulations (e.g., 14 CFR part 25) do not contain adequate or
appropriate safety standards for the Airbus Model A321neo XLR airplanes
because of a novel or unusual design feature, special conditions are
prescribed under the provisions of Sec. 21.16.
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, these special conditions would also apply to
the other model under Sec. 21.101.
In addition to the applicable airworthiness regulations and special
conditions, the Airbus Model A321neo XLR airplanes 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.
The FAA issues special conditions, as defined in Sec. 11.19, in
accordance with Sec. 11.38, and they become part of the type
certification basis under Sec. 21.101.
Novel or Unusual Design Features
The Airbus Model A321neo XLR airplanes will incorporate the
following novel or unusual design feature: Side-stick controllers for
pitch and roll control.
Discussion
These proposed special conditions for the Airbus A321neo XLR
airplane address the novel features of the side-stick controllers. The
A321neo XLR will incorporate side-stick controllers controlling a fly-
by-wire (FBW) electronic flight control system (EFCS). This system
provides an electronic interface between the pilot's flight controls
and the flight control surfaces for both normal and failure states, and
it generates the actual surface commands that provide for stability
augmentation and control about all three airplane axes. In addition,
pilot control authority may be uncertain, because the side-stick
controllers are not mechanically interconnected as with conventional
wheel and column controls.
Current FAA regulations do not specifically address the use of
side-stick controllers for pitch and roll control.
[[Page 46958]]
The unique features of the side stick must therefore be demonstrated
through flight and simulator tests to have suitable handling and
control characteristics when considering the following:
1. The handling-qualities tasks and requirements of the Airbus
Model A321neo XLR airplane special conditions, and other 14 CFR part 25
requirements for stability, control, and maneuverability, including the
effects of turbulence.
2. General ergonomics: Armrest comfort and support, local freedom
of movement, displacement angle suitability, and axis harmony.
3. Inadvertent input in turbulence.
4. Inadvertent pitch-roll crosstalk.
The FAA Handling Qualities Rating Method (HQRM) of Appendix E of
the Flight Test Guide for Certification of Transport Category
Airplanes, AC 25-7D, may be, but is not required to be, used to show
compliance.
These special conditions contain the additional safety standards
that the Administrator considers necessary to establish a level of
safety equivalent to that established by the existing airworthiness
standards.
Applicability
As discussed above, these special conditions apply to Airbus Model
A321neo XLR airplanes. Should Airbus apply later for a change to the
type certificate to include another model incorporating the same novel
or unusual design feature, the special conditions would apply to that
model as well.
Conclusion
This action affects only certain novel or unusual design features
on one model series of airplanes. It is not a rule of general
applicability.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
Authority Citation
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702, 44704.
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 Airbus Model A321neo XLR airplanes.
(a) Pilot Strength. In lieu of the ``strength of pilots'' limits of
Sec. 25.143(d) for pitch and roll, and in lieu of the specific pitch
force requirements of Sec. Sec. 25.145(b) and 25.175(d), the following
applies:
The applicant must show that the temporary and maximum prolonged
force levels for the side-stick controllers are suitable for all
expected operating conditions and configurations, whether normal or
non-normal.
(b) Controller Coupling. The electronic side-stick controller
coupling design must provide for corrective and/or overriding control
inputs by either pilot with no unsafe characteristics. Annunciation of
controller status must be provided and must not be confusing to the
flightcrew.
(c) Pilot Control. The applicant must show by flight tests that the
use of side-stick controllers does not produce unsuitable pilot-in-the-
loop control characteristics when considering precision path control
tasks and turbulence. In addition, pitch and roll control-force
sensitivity and displacement sensitivity must be compatible, so that
normal inputs on one control axis will not cause significant
unintentional inputs on the other.
Issued in Kansas City, Missouri, on July 17, 2023.
Patrick R. Mullen,
Manager, Technical Policy Branch, Policy and Standards Division,
Aircraft Certification Service.
[FR Doc. 2023-15466 Filed 7-20-23; 8:45 am]
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