AD 89-23-17

89-23-17 BOEING: Amendment 39-6385. Docket No. 89-NM-10-AD.

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

Compliance: Required as indicated, unless previously accomplished.

To detect cracking in the Number 1 or 3 engine aft mount support fitting, accomplish the following:

A. Conduct a detailed visual inspection for cracks of the Number 1 and Number 3 engine aft mount support fittings, in accordance with Section III.D and Figure 1 of Boeing Service Bulletin 727-54-0017, dated December 22, 1988, in accordance with the following schedule:

1. For airplanes with engine aft mount support fittings made of 7079-T6 material: within the next 1,000 flight cycles or 1 year, after the effective date of this AD, whichever occurs first, unless previously accomplished within the last 2,000 flight cycles.

NOTE: 7079-T6 material is used in the aft support fitting on the Number 1 engine strut on airplanes line numbers 001 through 883,and the Number 3 engine strut on airplanes line numbers 001 through 880.

2. For airplanes with engine aft support fittings made of 7075-T73 material: prior to the accumulation of 40,000 flight cycles, or within the next 1,000 flight cycles after the effective date of this AD, whichever occurs later, unless previously accomplished within the last 2,000 flight cycles.

NOTE: 7075-T73 material is used in the aft support fitting on the Number 1 engine strut on airplanes line number 884 and all later airplanes, and the Number 3 engine strut on airplanes line number 881 and all later airplanes.

B. For the initial inspection required in paragraph A., above, as an option to the detailed visual inspection, perform an eddy current inspection of the support fittings outboard of the body skins, and a detailed visual inspection of the support fittings inboard of the body skins, in accordance with Section III.A and Figure 1 of Boeing Service Bulletin 727-54-0017, dated December 22,1988.

C. Repeat the detailed visual inspection required in paragraph A., above, at intervals not to exceed 3,000 flight cycles.

D. If cracked fittings are found as a result of the inspections required by this AD, prior to further flight, accomplish one of the following:

1. Repair in accordance with Boeing Repair Drawings 65C34829, 65C34830, 65C34993, 65C34581, 65C35114, or 65C34998; or

2. Repair in accordance with a procedure approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region; or

3. Replace the cracked fittings.

E. 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, FAA, Northwest Mountain Region.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, SeattleAircraft Certification Office.

F. 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 Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

This amendment (39-6385, AD 89-23-17) becomes effective on December 11, 1989.