AD 90-26-54

90-26-54 BOEING: Amendment 39-6994. Docket 90-NM-284-AD. Final Rule of telegraphic AD.

Applicability: All Model 747-400 series airplanes, certificated in any category.

Compliance: Required within 10 days after the effective date of this AD, unless previously accomplished.

To prevent uncommanded leading edge flap retraction during takeoff roll, accomplish the following:

A. Revise the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to add the following statement. This may be accomplished by inserting a copy of this AD in the AFM.

"Dispatch with an inoperative thrust reverser is prohibited."

B. An alternate means of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

NOTE: The request should be submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Seattle ACO.

C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

This amendment (39-6994, AD 90-26-54) becomes effective on May 29, 1991, as to all persons, except those persons to whom it was made immediately effective by telegraphic AD T90-26-54, issued December 24, 1990, which contained this amendment.