[Federal Register Volume 79, Number 148 (Friday, August 1, 2014)]
[Rules and Regulations]
[Pages 44657-44658]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2014-18175]



Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2013-0899; Special Conditions No. 25-522-SC]

Special Conditions: Airbus Model A350-900 Airplane; Control-
Surface Awareness and Mode Annunciation

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.


SUMMARY: These special conditions are issued for Airbus Model A350-900 
airplanes. These airplanes have a novel or unusual design feature 
associated with control-surface awareness and mode annunciation 
provided by the electronic flight-control system. 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.

DATES: Effective Date: September 2, 2014.

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-



    On August 25, 2008, Airbus applied for a type certificate for their 
new Model A350-900 airplane. Later, Airbus requested and the FAA 
approved, an extension to the application for FAA type certification to 
November 15, 2009. The Model A350-900 airplane has a conventional 
layout with twin wing-mounted Rolls-Royce Trent XWB

[[Page 44658]]

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 Airbus Model A350-900 airplane configuration 
accommodates 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.
    These special conditions for control-surface awareness, applicable 
to Airbus Model A350-900 airplanes, require suitable flight-control-
position annunciation and control-system mode of operation to be 
provided to the flightcrew when a flight condition exists in which 
nearly full surface authority (not crew-commanded) is being utilized. 
Suitability of such a display must take into account that some pilot-
demanded maneuvers (e.g., rapid roll) are necessarily associated with 
intended full performance, which may saturate the surface. Therefore, 
simple alerting systems, which would function in both intended or 
unexpected control-limiting situations, must be properly balanced 
between needed crew awareness and nuisance features. A monitoring 
system that might compare airplane motion and surface deflection, and 
pilot side-stick controller (SSC) demand, could be useful for 
elimination of nuisance alerting.

Type Certification Basis

    Under Title 14, Code of Federal Regulations (14 CFR) 21.17, Airbus 
must show that the Model A350-900 airplane 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 airplane 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 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 A350-900 airplane 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 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 airplane incorporates the following novel 
or unusual design features: Electronic flight-control system providing 
control-surface awareness and mode annunciation to the flightcrew.


    With a response-command type flight-control system and no direct 
coupling from cockpit controller to control surface, the pilot is not 
aware of actual surface position utilized to fulfill the requested 
demand. Some unusual flight conditions, arising from atmospheric 
conditions and/or airplane or engine failures, may result in full or 
nearly full surface deflection. Unless the flightcrew is made aware of 
excessive deflection or impending control-surface limiting, piloted or 
auto-flight system control of the airplane might be inadvertently 
continued in such a manner as to cause loss of control or other unsafe 
stability or performance characteristics.
    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 

Discussion of Comments

    Notice of proposed special conditions No. 25-13-15-SC for Airbus 
Model A350-900 airplanes was published in the Federal Register on 
December 17, 2013 (78 FR 76254). No comments were received, and the 
special conditions are adopted as proposed.


    As discussed above, these special conditions apply to Airbus Model 
A350-900 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.


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

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 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 A350-900 airplanes.
    Current airworthiness standards do not contain adequate safety 
standards for the design. In addition to the requirements of Sec. Sec.  
25.143, 25.671 and 25.672, the following special conditions apply:
    1. The system design must ensure that the flightcrew is made 
suitably aware whenever the primary control means nears the limit of 
control authority.

    Note: The term ``suitably aware'' indicates annunciations 
provided to the flight crew that are appropriately balanced between 
nuisance and necessary crew awareness.

    2. If the design of the flight-control system has multiple modes of 
operation, a means must be provided to indicate to the crew any mode 
that significantly changes or degrades the normal handling or 
operational characteristics of the airplane.

    Issued in Renton, Washington, on July 11, 2014.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
[FR Doc. 2014-18175 Filed 7-31-14; 8:45 am]