AD 91-09-03

91-09-03 BOEING: Amendment 39-6968. Docket No. 90-NM-22-AD.

Applicability: All Model 727 series airplanes, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To prevent separation of an inboard trailing edge flap due to cracking, accomplish the following:

A. Except as provided in paragraph D. of this AD, perform a detailed visual inspection for cracks in the exposed areas of the inboard trailing edge flap inboard track at the main landing gear door forward hinge fitting attachment holes within the time specified in subparagraph 1., or 2., below, as applicable.

1. Prior to the accumulation of 7,000 flight cycles since manufacture or within the next 1,000 flight cycles after the effective date of this AD, whichever occurs later.

2. For flap tracks that were inspected and modified in accordance with Boeing Service Bulletin 727-32-340, Revision 1, dated December 10, 1987, Figure 1, prior to the accumulationof 9,000 flight cycles since modification, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later.

Repeat the inspections required by paragraphs A.1. and A.2. at intervals not to exceed 3,000 flight cycles.

NOTE: The hinge fitting bolts do not have to be removed to accomplish this inspection.

B. If cracked flap tracks are detected that do not exceed the limits specified in Figure 1 of Boeing Service Bulletin 727-32-0340, Revision 3, dated May 24, 1990, (hereafter referred to as "the service bulletin"), prior to further flight, repair in accordance with the service bulletin or replace the flap track. After repair, continue the repetitive inspections in accordance with paragraph A. of this AD.

C. If cracked flap tracks are detected that exceed the limits specified in Figure 1 of the service bulletin, prior to further flight, replace the track.

D. Flap tracks repaired in accordance with Boeing Drawing 65-68420 must be replacedwithin the time interval specified in subparagraph 1. or 2., below, whichever occurs later.

1. Within 2,000 flight cycles or 1 year since repair, whichever occurs first; or

2. Within 1,000 flight cycles or 6 months after the effective date of this AD, whichever occurs first.

E. Inspection and modification in accordance with Figure 1 of Boeing Service Bulletin 727-32-340, Revision 2, dated September 7, 1989, or Revision 3, dated May 24, 1990, and replacement of cracked forward hinge fittings, constitutes terminating action for the inspections required by paragraph A. of this AD. There must be no flight cycles accumulated between the accomplishment of the inspection, replacement of cracked forward hinge fittings, and modification.

F. 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.

G. 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.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington.

This amendment (39-6968, AD 91-09-03) becomes effective on May 28, 1991.