Proposed Rules. Notice of proposed special conditions

Agency: Federal Aviation Administration (FAA), DOT
Action: Notice of proposed special conditions
Citation: FR Doc. 2014-00100 · Docket No. FAA-2013-0901; Notice No. 25-13-23-SC · 14 CFR 25

Summary

This action proposes special conditions for Airbus Model A350-900 series airplanes. These airplanes will have a novel or unusual design feature associated with high speed limiting. 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 7, 2014.

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 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. The longitudinal control law design of the Airbus Model A350-900 incorporates an overspeed protection system in the normal mode; this would prevent the pilot from inadvertently or intentionally exceeding a speed approximately equivalent to V ^FC or attaining V ^DF . Current Title 14 Code of Federal Regulations (14 CFR) part 25 sections do not relate to a high speed limiting protection system that might preclude or modify flying qualities assessments in the overspeed region. However, the requirements of § 25.253 (High-speed characteristics) and its related policy are applicable to the Model A350-900 series and not affected by this proposed special condition. 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 25-129. 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 series because of a novel or unusual design feature, special conditions are prescribed under § 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 § 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 § 11.38, and they become part of the type-certification basis under § 21.17(a)(2). Novel or Unusual Design Features The Model A350-900 series will incorporate the following novel or unusual design features: An overspeed protection system which prevents the pilot from inadvertently or intentionally exceeding a speed approximately equivalent to V ^FC or attaining V ^DF . At V ^MO + 10 knots or M ^MO + 0.02, an automatic nose up pitch is applied with phase advance in case of high acceleration. The speed stabilizes at V ^D − 10kts/M ^D − 0.02 if the stick is full forward, or the speed will return below V ^MO /M ^MO if the stick is released. Discussion This proposed special condition establishes requirements to ensure that operation of the high speed limiting protection system does not impede normal attainment of speeds up to the overspeed warning. Its main features are: 1. It protects the airplane against high speed/high Mach number flight conditions beyond V ^MO /M ^MO . 2. It does not interfere with flight at V ^MO /M ^MO , even in turbulent air. 3. It still provides load factor limitation through the “pitch limiting” function described below. 4. It restores positive static stability beyond V ^MO /M ^MO . 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 condition as part of the type certification basis for Airbus Model A350-900 series airplanes. In addition to § 25.143, the following requirements apply: Operation of the high speed limiter during all routine and descent procedure flight must not impede normal attainment of speeds up to overspeed warning Issued in Renton, Washington, on October 22, 2013. Stephen P. Boyd, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 2014-00100 Filed 1-7-14; 8:45 am]