AD 91-07-51

91-07-51 BOEING: Amendment 39-7004. Docket No. 91-NM-84-AD.

Applicability: Model 757 series airplanes, line number 154 through 350, except line numbers 332 and 340, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To detect improperly installed nuts in the upper and lower attachment of the rudder yaw damper pogo assembly, accomplish the following:

A. Within the next 60 flight cycles or 20 days after the effective date of this AD, whichever occurs sooner, inspect the upper and lower attachment of the rudder yaw damper pogo assembly for improper installation of the nuts in accordance with Boeing Telegram M-7272-91- 1886, dated March 22, 1991. If less than one thread from the bolt protrudes through the nut, or if the nut is or appears to be cross threaded, replace both the nut and bolt prior to further flight.

B. Within 10 days after completion of the inspection required by paragraph A. of this AD, submit a report of findings of discrepancies to the Manager, Seattle Manufacturing Inspection District Office, ANM-108S, FAA, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington 98055-4056; fax: (206) 227-1181.

C. An alternative method 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 forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO.

D. 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.

The inspection shall be done in accordance with Boeing Telegram M-7272-91-1886, dated March 22, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington, or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C.

This amendment (39-7004, AD 91-07-51) becomes effective on July 1, 1991, as to all persons, except those persons to whom it was made immediately effective by telegraphic AD T91-07-51, issued March 27, 1991, which contained this amendment.