Special Conditions: Airbus, Model A350-900 series Airplane; Pitch and Roll Limiting by Electronic Flight Control System, 67320-67321 [2013-26928]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 78, Number 218 (Tuesday, November 12, 2013)]
[Proposed Rules]
[Pages 67320-67321]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-26928]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR part 25

[Docket No. FAA-2013-0902; Notice No. 25-13-25-SC]


Special Conditions: Airbus, Model A350-900 series Airplane; Pitch 
and Roll Limiting by Electronic Flight Control System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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SUMMARY: This action proposes special conditions for the Airbus Model 
A350-900 series airplanes. This airplane will have a novel or unusual 
design feature(s) associated with the Electronic Flight Control System 
that limits pitch and roll attitude functions. The applicable 
airworthiness regulations do not contain adequate or appropriate safety 
standards for this design feature. These proposed 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.

DATES: We must receive your comments by December 27, 2013.

ADDRESSES: Send comments identified by docket number FAA-2013-0902 
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: The FAA will post all comments it receives, without change, to 
https://www.regulations.gov/, including any personal information the 
commenter provides. Using the search function of the docket Web site, 
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 https://DocketsInfo.dot.gov/.
    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 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: Joe Jacobsen, FAA, Airplane and 
Flightcrew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington, 98057-3356; telephone (425) 227-2011; facsimile (425) 227-
1320.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite 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.
    We will consider all comments we receive on or before the closing 
date for comments. We may change these proposed special conditions 
based on the comments we receive.

Background

    On August 25, 2008, Airbus applied for a type certificate for their 
new Model A350-900 series airplane. Later, Airbus requested and the FAA 
approved an extension to the application for FAA type certification to 
June 28, 2009, The Model A350-900 series has a conventional layout with 
twin wing-mounted Rolls-Royce Trent engines. It features a twin aisle 
9-abreast economy class layout, and accommodates side-by-side placement 
of LD-3 containers in the cargo compartment. The basic Model A350-900 
series configuration will accommodate 315 passengers in a standard two-
class arrangement. The design cruise speed is Mach 0.85 with a Maximum 
Take-Off Weight of 602,000 lbs. Airbus proposes the Model A350-900 
series to be certified for extended operations (ETOPS) beyond 180 
minutes at entry into service for up to a 420-minute maximum diversion 
time.
    A special condition to supplement Sec.  25.143 concerning pitch and 
roll limits was developed for the Airbus A320, A330, A340, and A380 
Models wherein performance of the limiting functions was monitored 
throughout the flight test program. The FAA expects similar monitoring 
to take place during the A350 flight test program in order to 
substantiate the pitch and roll attitude limiting functions and the 
appropriateness of the chosen limits.

Type Certification Basis

    Under Title 14, Code of Federal Regulations (14 CFR) 21.17, Airbus 
must show that the Model A350-900 series meets the applicable 
provisions of 14 CFR part 25, as amended by Amendments 25-1 through 25-
128.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 14 CFR part 25) do not contain adequate or 
appropriate safety standards for the Model A350-900 series because of a 
novel or unusual design feature, special conditions are prescribed 
under 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 or similar 
novel or unusual design feature, the proposed special conditions would 
also apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and 
proposed special conditions, the Model A350-900 series 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 Sec.  611 of Public Law 
92-574, the ``Noise Control Act of 1972.''

[[Page 67321]]

    The FAA issues special conditions, as defined in 14 CFR 11.19, 
under Sec.  11.38, and they become part of the type-certification basis 
under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The Airbus Model A350-900 series will incorporate the following 
novel or unusual design features: an Electronic Flight Control system 
(EFCS), that when operating in its normal mode, will prevent airplane 
pitch attitudes greater than +30 degrees and less than -15 degrees, and 
roll angles greater than plus or minus 67 degrees. In addition, 
positive spiral stability is introduced for roll angles greater than 33 
degrees at speeds below VMO/MMO. At speeds 
greater than VMO and up to VDF, maximum aileron 
control force is limited to only 45 degrees maximum bank angle.

Discussion

    It is expected that high thrust-to-weight ratios will provide the 
most critical cases for the positive pitch limit. A margin in pitch 
control must be available to enable speed control in maneuvers such as 
climb after takeoff, and balked landing climb. The pitch limit must not 
impede likely maneuvering made necessary by collision avoidance 
efforts. A negative pitch limit must similarly not interfere with 
collision avoidance capability or with attaining and maintaining speeds 
near VMO/MMO for emergency descent.
    Spiral stability, which is introduced above 33 degrees roll angle, 
and the roll limit must not restrict attaining roll angles up to 66 
degrees (approximately 2.5g level turn) with flaps up and 60 degrees 
(approximately 2.0g level turn) with flaps down. The implementation of 
this spiral stability will require a steady aileron control force to 
maintain a constant bank angle above 33 degrees. This force must not 
require excessive pilot strength as stated in Sec.  25.143(f).

Applicability

    As discussed above, these proposed special conditions apply to 
Airbus Model A350-900 series 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 proposed special 
conditions would apply to that model as well.

Conclusion

    This action affects only certain novel or unusual design features 
on the Airbus Model A350-900 series airplanes. It is not a rule of 
general applicability.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and recordkeeping 
requirements.

    The authority citation for these special conditions is as follows:

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

The Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for Airbus Model A350-900 series airplanes.
    In addition to Sec.  25.143, the following requirements apply:
    1. The pitch limiting function must not impede normal maneuvering 
for pitch angles up to the maximum required for normal maneuvering, 
including a normal all-engines operating takeoff, plus a suitable 
margin to allow for satisfactory speed control.
    2. The pitch and roll limiting functions must not restrict or 
prevent attaining pitch attitudes necessary for emergency maneuvering 
or roll angles up to 66 degrees with flaps up, or 60 degrees with flaps 
down. Spiral stability, which is introduced above 33 degrees roll 
angle, must not require excessive pilot strength to achieve these limit 
roll angles. Other protections, which further limit the roll capability 
under certain extreme angle of attack or attitude or high speed 
conditions, are acceptable, as long as they allow at least 45 degrees 
of roll capability.

    Issued in Renton, Washington, on October 22, 2013.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-26928 Filed 11-8-13; 8:45 am]
BILLING CODE 4910-13-P