1AD/B747/136 Amdt 1 - Fuselage - Nose Wheel Well

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 747 Series Aeroplanes

AD/B747/136

Amdt 1

Fuselage - Nose Wheel Well 7/99

Applicability: B747 Line No 001 to 685 inclusive.

Requirement: 1. Externally inspect for cracks in the nose wheel well top panel and intercostals. Inspect in accordance with Boeing SB 747-53-2293 Rev 6 using either detailed close visual (Option 1) or a combination of detailed close visual and high frequency eddy current (Option 2) methods.

2. Perform a detailed close visual inspection, internally and externally, for cracks in the nose wheel well vertical beam clips and the adjacent side wall panel web. If cracks are found, extend the inspection area and inspect using high frequency eddy current methods. Inspect in accordance with Boeing SB 747-53-2293 Rev 6.

3. Inspect, internally and externally, for cracks in the nose wheel well vertical beam webs. Inspect in accordance with Boeing SB 747-53-2293 Rev 6 using either a detailed close visual (Option 1) or a combination of detailed close visual and high frequency eddy current (Option 2) methods.

Note: FAA AD 90-06-14R1 refers.

Compliance: 1. Initially inspect the nose wheel well top panel and intercostals before 4000 flights or within 1500 flights from 27 April 1995, whichever is the later. Reinspect at intervals not exceeding 1500 flights (Option 1) or intervals not exceeding 3000 flights (Option 2).

2. Initially inspect the vertical beam clips and side wall panels before 10000 flights or within 1500 flights from 27 April 1995, whichever is the later. Reinspect at intervals not exceeding 3000 flights.

3. Inspect the vertical beam webs before 10000 flights or before 1500 flights from 27 April 1995, whichever is the later. Reinspect at intervals not exceeding 1500 flights (Option 1) or intervals not exceeding 3000 flights (Option 2).

4. For the purposes of this AD a flight may be taken as a ground-air-ground cycle where the pressure differential exceeds 2.0 psi.

5. Modification in accordance with Boeing SB 747-53-2293 Rev 6 constitutes terminating action for the inspection requirements of this AD for those areas so modified.

The compliance times of the original issue of this Directive remains unchanged except for the Requirement 2 repetitive inspection.

This Amendment becomes effective on 15 July 1999.

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

SCHEDULE OF AIRWORTHINESS DIRECTIVES