COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/149 Fuselage Skin Above Forward Entry Doors 7/95
Applicability: B747 aircraft, line numbers 1 to 206 inclusive.
Requirement: 1. Inspect the fuselage skin at the aft row of fasteners between stringers S-14E and S- 16 at the left and right Body Station (BS) 460 circumferential splice for cracks.
Inspect, using the high frequency eddy current (HFEC) method, in accordance with Boeing Service Bulletin (SB) 747-53-2289, Revision 2.
For aircraft which have not been modified in accordance with Boeing SB 747-53- 2181 or SB 747-53-2105, do an additional HFEC inspection of the forward row of fasteners of the BS 460 circumferential splice. Inspect in accordance with Boeing SB 747-53-2289, Revision 2.
2. Modify the aft side of the left hand and right hand lap splices between stringers 14E and 16 in accordance with Boeing SB 747-53-2289 Revision 2. If not already accomplished, modify the forward side of the left hand and right hand lap splices between stringers 14E and 16 in accordance with either Boeing SB 747-53-2181 or 747-53-2105.
Note: FAA AD 89-21-09 refers.
Compliance: 1. Inspect before 10 000 flights or before 1000 flights after 22 June 1995, whichever occurs last.
Re-inspect at intervals not to exceed 3000 flights.
2. Modify before 20 000 flights.
Modification in accordance with Requirement 2 cancels the inspection requirements of this Directive.
Background: Operators have reported numerous skin cracks up to 15 inches long at the rear fastener row of the BS 460 circumferential skin splice. If allowed to remain un- repaired the cracking could result in a rapid decompression.
The requirements of this AD are in accordance with the Boeing 747 Structures Working Group recommendations.