Final special conditions.
CFR Part: "14 CFR Part 25"
Citation: "79 FR 46170"
Document Number: "Docket No.
"Rules and Regulations"
SUMMARY: These special conditions are issued for Airbus Model A350-900 airplanes. These airplanes will have a novel or unusual design feature associated with side-stick controllers for pitch and roll control, instead of conventional wheels and columns. 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.
EFFECTIVE DATE: Effective Date:
FOR FURTHER INFORMATION CONTACT:
The Airbus Model A350-900 airplane, like its predecessors the Model A320, A330, A340 and A380 airplanes, will use side-stick controllers for pitch and roll control. Regulatory requirements pertaining to conventional wheel and column controls, such as pilot strength and controllability, are not directly applicable for the side stick. In addition, pilot-control authority may be uncertain because the side sticks are not mechanically interconnected as with conventional wheel and column controls.
Type Certification Basis
Under Title 14, Code of Federal Regulations (14 CFR) 21.17,
The FAA has determined that Airbus Model A350-900 airplanes must comply with SUBSEC 25.143, 25.145(b), 25.175(b), 25.671, and 25.1329(a).
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 Airbus Model A350-900 airplane because of a novel or unusual design feature, special conditions are prescribed under
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
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
The FAA issues special conditions, as defined in 14 CFR 11.19, under
Novel or Unusual Design Features
The Airbus Model A350-900 airplane will incorporate the following novel or unusual design features: side-stick controllers for pitch and roll control, in place of conventional wheel and column controls.
Current FAA regulations do not specifically address the use of side-stick controllers for pitch and roll control. 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 A350 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 Handling Qualities Rating Method (HQRM) of Appendix 5 of the Flight Test Guide, AC 25-7C, may 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.
Discussion of Comments
Notice of proposed special conditions no. 25-13-26-SC for Airbus Model A350-900 airplanes was published in the
As discussed above, these special conditions apply to Airbus Model A350-900 airplanes. Should
This action affects only certain novel or unusual design features on Airbus Model A350-900 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 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.
1. Pilot strength: In lieu of the "strength of pilots" limits shown in
2. Pilot-control authority: 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 the controller status must be provided, and must not be confusing to the flightcrew.
3. Pilot control: It must be shown 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 and displacement sensitivity must be compatible, so that normal inputs on one control axis will not cause significant unintentional inputs on the other.
[FR Doc. 2014-18658 Filed 8-6-14;
BILLING CODE 4910-13-P
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