### 1336 Federal Register / Vol. 79, No. 5 / Wednesday, January 8, 2014 / Proposed Rules

2 Cherry, R. and Warren, K. ‘‘Fuselage Burnthrough Protection for Increased Postcrash Occupant Survivability: Safety Benefit Analysis Based on Past Accidents, ‘‘FAA Report DOT/FAA/ AR–99/57, September 1999 and R G W Cherry & Associates Limited, ‘‘A Benefit Analysis for Cabin Water Spray Systems and Enhanced Fuselage Burnthrough Protection,’’ FAA Report DOT/FAA/ AR–02/49, April 7, 2003. are the structural integrity of the wingand tank, flammability of the tank, burnthrough resistance of the wing skin, and the presence of auto-ignition threats during exposure to a fire. The FAA assessed post-crash survival time during the adoption of Amendment 25–111 for fuselage burn-through protection. Studies conducted by and on behalf of the FAA indicated that, following a survivable accident, prevention of fuselage burn-through for approximately 5 minutes can significantly enhance survivability. 2

There is little benefit in requiring thedesign to prevent wing skin burnthrough beyond five minutes, due to the effects of the fuel fire itself on the rest of the airplane. That assessment was carried out based on accidents involving airplanes with conventional fuel tanks, and considering the ability of ground personnel to rescue occupants. In addition, AC 20–135 indicates that, when aluminum is used for fuel tanks, the tank should withstand the effects of fire for 5 minutes without failure. Therefore, to be consistent with existing capability and related requirements, the Model A350–900 series airplane fuel tanks must be capable of resisting a post-crash fire for at least 5 minutes. In demonstrating compliance, Airbus must address a range of fuel loads from minimum to maximum, as well as any other critical fuel load. 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 under the provisions of § 21.101.

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, pursuant to the authority delegated to me by the Administrator, the following special conditions are proposed as part of the type certification basis for the Model A350–900 series airplane:

In addition to complying with 14 CFRpart 25 regulations governing the firesafety performance of the fuel tanks, wings, and nacelle, the Airbus Model A350–900 series airplane must demonstrate acceptable post-crash survivability in the event the wings are exposed to a large fuel-fed ground fire. Airbus must demonstrate that the wing and fuel tank design can endure an external fuel-fed pool fire for at least five minutes. This shall be demonstrated for minimum fuel loads (not less than reserve fuel levels) and maximum fuel loads (maximum range fuel quantities), and other identified critical fuel loads. Considerations shallinclude fuel tank flammability, burnthrough resistance, wing structuralstrength retention properties, and autoignition threats during a ground fire event for the required time duration.

Issued in Renton, Washington, on October 22, 2013. Stephen P. Boyd Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2014–00102 Filed 1–7–14; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 25**

**[Docket No. FAA–2013–0901; Notice No. 25–13–23–SC]** 

**Special Conditions: Airbus, Model A350–900 Series Airplane; Flight**  **Envelope Protection: High Speed Limiting** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Notice of proposed special conditions.

**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.

**ADDRESSES :**  Send comments identified by docket number FAA–2013–0901 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.

**FOR FURTHER INFORMATION CONTACT :**  Joe Jacobsen, FAA, Airplane and 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) 227–1320.

**SUPPLEMENTARY INFORMATION :** 
Comments Invited

We invite interested people to take part in this rulemaking by sending


### 1337 Federal Register / Vol. 79, No. 5 / Wednesday, January 8, 2014 / Proposed Rules

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 aconventional layout with twin wingmounted Rolls-Royce Trent engines. It features a twin aisle 9-abreast economyclass layout, and accommodates side-byside 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 typecertification 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 VFC 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 VMO /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 VMO /M MO .

2. It does not interfere with flight at VMO /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]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 25**

**[Docket No. FAA–2013–0892; Notice No. 25–13–21–SC]** 

**Special Conditions: Airbus, A350–900 Series Airplane; Crashworthiness—**  **Emergency Landing Conditions**

**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. These airplanes will have a novel or unusual design feature associated with crashworthiness of carbon fiber reinforced plastic used in the construction of the fuselage. 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