03-22209. Additional Requirements: Aquila GmbH Engine Mount Connection Design Criteria and Winglets for the Aquila GmbH AT01 JAR-VLA Airplane

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of availability of proposed design criteria and request for comments.

SUMMARY:

This notice announces the availability of and requests comments on the proposed design criteria for fire protection of the connection between the metal structure of an engine mount and composite airframe on an Aquila GmbH AT01 single-engine aircraft with winglets on the wings. This airplane will be certified under the requirements of JAR-VLA (Joint Aviation Requirements—Very Light Aircraft) Amendment VLA/92/01 as developed by the Joint Aviation Authority, and under Title 14 of the Code of Federal Regulations. Additional provisions addressing JAR-VLA parts 865, 1191, and 445 were issued by the airworthiness authority for Germany, the Luftfahrt-Bundesamt (LBA). The FAA is issuing the same additional requirements.

DATES:

Comments must be received on or before October 2, 2003.

ADDRESSES:

Send all comments on the proposed design criteria to: Federal Aviation Administration, Attention: Mr. Karl Schletzbaum, Project Support Office, ACE-112, 901 Locust, Kansas City, Missouri 64106. Comments may be inspected at the above address between 7:30 a.m. and 4 p.m. weekdays, except Federal holidays.

FOR FURTHER INFORMATION CONTACT:

Mr. Karl Schletzbaum, 816-329-4146.

SUPPLEMENTARY INFORMATION:

Comments Invited

Interested persons are invited to comment on the proposed policy by submitting such written data, views, or arguments as they may desire. Commenters should identify the proposed design criteria on the Aquila GmbH engine mount and winglets, and submit comments, in duplicate, to the address specified above. All communications received on or before the closing date for comments will be considered by the Small Airplane Directorate before issuing the final design criteria.

Discussion

Proposed Design Criteria

This airplane will be certified under the requirements of JAR-VLA (Joint Aviation Requirements—Very Light Aircraft) Amendment VLA/92/01 as developed by the Joint Aviation Authority and 14 CFR 21.17.

Additional Requirements: Engine Mount Connection Design Criteria

The Aquila AT01 is a full composite single-engine aircraft with the engine mount fitted to the glass fiber composite fuselage. The airplane will be certified to the requirements of JAR/VLA 865 (Fire protection of flight controls and other flight structure) and JAR/VLA 1191 (Firewalls). However, tests must be performed that demonstrate that the interface between the metallic engine mount and the glass fiber reinforced plastic fuselage withstand a fire for 15 minutes while carrying loads under the following conditions:

(a) With one lost engine mount fitting the loads are distributed over the remaining 3 engine mount fittings. The most critical of these fittings must be chosen for the test.

(1) The loads are:

(i) in Z-direction the mass of the propulsion unit multiplied by a maneuvering load factor resulting from a 30° turn for 15 minutes, superimposed by a maneuvering load of 3 seconds representing the maximum positive limit maneuvering load factor of n=3.8 arising from JAR/VLA 337(a).

(ii) in X-direction the engine propulsion force at maximum continuous power for 5 minutes.

(b) The flame to which the component test arrangement is subjected must provide a temperature of 500° C within the target area.

(c) The flame must be large enough to maintain the required temperature over the entire test zone, i.e., the fitting on the engine compartment side.

(d) It must be shown that the test equipment, e.g., burner and instrumentation are of sufficient power, size, and precision to yield the test requirements arising from paragraphs (a) to (c) above. Guidance will be drawn from advisory material AC 20-135 to AC 23-2.

Additional Requirements: Winglets

Since winglets, as a specific structural element, are not addressed in the JAR/VLA requirements, the following is required:

Compliance must be demonstrated to the requirements of JAR 23.445—Outboard fins or winglets.

Issued in Kansas City, Missouri, on August 15, 2003.

Diane K. Malone,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.