1AD/B727/155 - Fuselage Skin Lap Joints

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 727 Series Aeroplanes

AD/B727/155 Fuselage Skin Lap Joints 1/99 DM

Applicability: Model 727 series aircraft, line positions 1 through 849; that have been converted from a passenger-carrying to a cargo-carrying (freighter) configuration, or to a passenger- and cargo-carrying (combi) configuration.

Requirement: 1. Perform a detailed internal visual inspection to detect cracking, corrosion, or delamination of the fuselage skin lap joints where those lap joints are covered by external doublers at stringers S-4L, S-10L, S-19L, and S-26L from Body Station 360 to 740; in accordance with task numbers C53-224-01 and C53-111-01 of Boeing Document D6-54929, Aging Airplane Corrosion Prevention and Control Program, Model 727, Revision A, dated July 28, 1989. The lap joints must be completely exposed to perform the inspection.

If any crack, corrosion, or delamination is found, before further flight, repair damaged structure in accordance with a method approved by the Authority.

2. Modify the fuselage skin lap joints where those lap joints are covered by external doublers at stringers S-4L, S-10L, S-19L, and S-26L from Body Station 360 to 740 by removing the external doublers; and by separating and reworking the joint in accordance with Part IV, Figure 4, of the Accomplishment Instructions of Boeing Service Bulletin 727-53-0072, Revision 5, dated June 1, 1989, except that blind fasteners shall not be installed.

Note 1: If an operator can verify that the modification required by this Directive has, in fact, been accomplished, a request for exemption should be submitted to the Authority with data verifying such accomplishment.

Before oversizing the fastener holes as part of the modification, perform a high frequency eddy current inspection of the holes to detect cracking, in accordance with the service bulletin; and before further flight, repair any cracking in accordance with a method approved by the Authority.

When reassembling the lap joint, all three rows of fasteners must penetrate all layers of the lap joint, including the upper skin, lower skin, and the doublers; and the stringers and tripler, as applicable.

Note 2: Installation of protruding head fasteners in the upper row of fasteners of the lap joint in itself does not constitute accomplishment of the modification.

For aircraft on which the cargo door itself was manufactured using the original fuselage skin, Requirements 1 and 2 also apply to the lap joint(s) in the door structure.