AD 84-19-01

84-19-01 BOEING: Amendment 39-4913. Applies to Boeing Model 747 series airplanes, certificated in all categories, listed in Boeing Service Bulletin 747-53-2088, Revision 2, or later FAA approved revisions.

To detect cracks and prevent failure of the frame to tension tie joint structure, accomplish the following unless already accomplished:

A. For airplanes that have not been modified in accordance with Service Bulletin 747- 53-2088, within the next 500 landings after the effective date of this AD or prior to the accumulation of 8,000 landings, whichever is later, perform a close visual inspection of the tension tie at body station (BS) 760 on Group I and Group II airplanes, and at BS 780 on Group III airplanes, for cracks in the areas identified in Service Bulletin 747-53-2088, Revision 2, or later FAA approved revisions. Repeat inspections at intervals not to exceed 3700 landings. If cracks are found, repair and modify in accordance with Service Bulletin 747-53-2088, Revision 2, or later FAA approved revisions, prior to further pressurized flight. Inspections are to continue after repair.

B. For airplanes that have been modified in accordance with Service Bulletin 747-53- 2088, within the next 1000 landings after the effective date of this AD or prior to the accumulation of 10,000 landings after modification, whichever is later, perform a close visual inspection of the tension tie at BS 760 on Group I and Group II airplanes, and at BS 780 on Group III airplanes, for cracks in the areas identified for inspection in Service Bulletin 747-53- 2088, Revision 2, or later FAA approved revisions. Repeat inspections at intervals not to exceed 8000 landings. If cracks are found, repair in accordance with Service Bulletin 747-53-2088, Revision 2, or later FAA approved revisions, prior to further pressurized flight. Inspections are to continue after repair.

C. Alternate means of compliance with the AD which provide an equivalent level of safety maybe used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.

D. For purposes of complying with this AD, subject to acceptance by the assigned FAA Maintenance Inspector, the number of landings may be determined by dividing each airplane's time in service by the operator's fleet average time from takeoff to landing for the airplane type.

E. Aircraft may be ferried to a base for maintenance in accordance with Section 21.197 and 21.199 of the Federal Aviation Regulations.

F. Upon request of the operator, an FAA Maintenance Inspector, subject to prior approval of the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region, may adjust the inspection times specified in this AD to permit compliance at an established inspection period of an operator, if the request contains substantiating data to justify the adjustment period.

This amendment becomes effective October 19, 1984.