[Federal Register Volume 79, Number 9 (Tuesday, January 14, 2014)]
[Proposed Rules]
[Pages 2387-2388]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-00448]



Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0900; Notice No. 25-12-08-SC]

Special Conditions: Airbus, Model A350-900 Series Airplane; 
General Limiting Requirements

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.


SUMMARY: This action proposes special conditions for the Airbus Model 
A350-900 series airplanes. This airplane will have a novel or unusual 
design feature associated with general limiting requirements of its 
flight envelope protection features. 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: Send your comments on or before February 28, 2014.

ADDRESSES: Send comments identified by docket number FAA-2013-0900 
using any of the following methods:
     Federal eRegulations 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 (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 http://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 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.

Flightcrew Interface, ANM-111, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057-
3356; telephone (425) 227-2011; facsimile (425) 227-1320.


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 ask 
that you send us two copies of written comments.
    We will consider all comments we receive on or before the closing 
date for comments. We may change these special conditions based on the 
comments we receive.


    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

[[Page 2388]]

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.
    Flight envelope protection is the subject of several proposed 
special conditions for the A350. Each specific type of envelope 
protection is addressed individually, but some requirements are common 
to all limiting systems and are therefore put forth as general limiting 

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-
    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 section 611 of Public Law 
92-574, the ``Noise Control Act of 1972.''
    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: General Limiting Requirements for the 
flight envelope protection system.


    This proposed special condition and the following ones which 
pertain to flight envelope protection present general limiting 
requirements for all the unique flight envelope protection features of 
the basic A350 Electronic Flight Control System (EFCS) design. Current 
regulations do not address these types of protection features. The 
general limiting requirements are necessary to ensure a smooth 
transition from normal flight to the protection mode and adequate 
maneuver capability. The general limiting requirements also ensure that 
the structural limits of the airplane are not exceeded. Furthermore, 
failure of the protection feature must not create hazardous flight 
conditions. Envelope protection parameters include angle of attack, 
normal load factor, bank angle, pitch angle, and speed. To accomplish 
these envelope protections, one or more significant changes occur in 
the EFCS control laws as the normal flight envelope limit is approached 
or exceeded.


    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.


    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 

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.
    1. General Limiting Requirements.
    a. Onset characteristics of each envelope protection feature must 
be smooth, appropriate to the phase of flight and type of maneuver, and 
not in conflict with the ability of the pilot to satisfactorily change 
airplane flight path, speed, or attitude as needed.
    b. Limit values of protected flight parameters (and if applicable, 
associated warning thresholds) must be compatible with the following:
    (1) Airplane structural limits,
    (2) Required safe and controllable maneuvering of the airplane, and
    (3) Margins to critical conditions. Unsafe flight characteristics/
conditions must not result if dynamic maneuvering, airframe and system 
tolerances (both manufacturing and in-service), and non-steady 
atmospheric conditions, in any appropriate combination and phase of 
flight, can produce a limited flight parameter beyond the nominal 
design limit value.
    c. The airplane must be responsive to intentional dynamic 
maneuvering to within a suitable range of the parameter limit. Dynamic 
characteristics such as damping and overshoot must also be appropriate 
for the flight maneuver and limit parameter in question.
    d. When simultaneous envelope limiting is engaged, adverse coupling 
or adverse priority must not result.
    2. Failure States
    EFCS failures (including sensor) must not result in a condition 
where a parameter is limited to such a reduced value that safe and 
controllable maneuvering is no longer available. The crew must be 
alerted by suitable means if any change in envelope limiting or 
maneuverability is produced by single or multiple failures of the EFCS 
not shown to be extremely improbable.

    Issued in Renton, Washington, on October 22, 2013.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
[FR Doc. 2014-00448 Filed 1-13-14; 8:45 am]