Final special conditions.
CFR Part: "14 CFR Part 25"
Citation: "79 FR 44658"
Document Number: "Docket No.
"Rules and Regulations"
SUMMARY: These special conditions are issued for the Airbus Model A350-900 airplane. This airplane will have a novel or unusual design feature associated with the electronic flight-control system (EFCS) that limits pitch- and roll-attitude functions. 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:
A special condition to supplement
Type Certification Basis
Under Title 14, Code of Federal Regulations (14 CFR) 21.17,
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
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 final special conditions, the 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 series will incorporate the following novel or unusual design features: an 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.
It is expected that high thrust-to-weight ratios 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 requires 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
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. 25-13-25-SC for the Airbus Model A350-900 airplane 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 the 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. In addition to
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 roll-limit angles. Other protections, which further limit the roll capability under certain extreme angle-of-attack, attitude, or high-speed conditions, are acceptable as long as they allow at least 45 degrees of roll capability.
[FR Doc. 2014-18176 Filed 7-31-14;
BILLING CODE 4910-13-P
Most Popular Stories
- 2016 Camaro Shrinks, Moves to Caddy Platform
- More Hispanic Voters May Not Mean More Clout
- Eric Garcia Appointed as Revenue Chief
- Tablets, Cars Drive AT&T Gains
- Apple Pay Debuts With Few Issues
- New Effort to Ban Child Labor From Tobacco Farms
- Stocks Subdued After Gains Earlier in Week
- Government: 500 Million Records Stolen in 12 Months
- Pistorius Gets 5-year Sentence in Shooting Death
- Mom Makes Toys R Us Pull 'Breaking Bad' Dolls