COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/132 Fuselage - Upper Lobe Skin Panel Joints 11/94
Applicability: Boeing 747 series aircraft line positions 001 to 200 inclusive.
Requirement: 1. Initially, perform a detailed external visual inspection of the upper lobe skin panel lap joints for evidence of corrosion or cracking in accordance with Boeing SB 747- 53-2307 Revision 2, within 1000 flights after 13 October 1994.
Repeat at intervals not exceeding 2000 flights.
2. Initially, perform a HFEC inspection to detect cracks in the upper row of fasteners of the skin panel lap joints forward of BS 1000 in accordance with Boeing SB 747- 53-2307 Revision 2, within 1000 flights after 13 October 1994.
Repeat at intervals not exceeding 4000 flights.
3. Initially, perform a HFEC inspection to detect cracks in the upper row of fasteners of the skin panel lap joints between BS 1480 and 2360 in accordance with Boeing SB 747-53-2307 Revision 2, within 1000 flights after 13 October 1994.
Repeat at intervals not exceeding 6000 flights.
Note: It is required that all fastener heads are readily visible prior to conducting any of the above inspections. If necessary the lap joint shall be paint stripped.
4. If corrosion is found but does not exceed 10% of the skin thickness, on the affected lap joint:
- Inspect the area using HFEC inspection at reduced intervals not exceeding 500 flights, and
b. Install the “full” modification in SB 747-53-2307 Revision 2 within 36 months of the inspection during which the corrosion was found.
5. If cracks or corrosion exceeding 10% of the thickness are found, repair before further flight and install the “full” modification within 18 months of the inspection during which the corrosion was found.
6. Install the “full” modification, before 20000 flights or within 1000 flights from 13 October 1994, whichever is the later, at:
- The skin lap joints between stringer 12 left and right from BS 520 to 1000 and between stringer 19 left and right from BS 520 to 740 on aircraft line numbers 001 to 058 inclusive, or
b. The skin lap joints between stringer 12 left and right from BS 740 to 1000 and between stringer 19 left and right from BS 520 to 740 on aircraft line numbers 059 to 200 inclusive,
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
The inspections in paragraphs 1 to 4 are no longer required after “full” or “partial” modification in accordance with SB 747-53-2307 Revision 2.
7. HFEC inspect the modified lap joints:
- Initially, within 10000 flights from installing the “full” modification. Repeat at intervals not exceeding 3000 flights.
b. Initially, within 7000 flights from installing the “partial” modification. Repeat at intervals not exceeding 3000 flights.
8. The “partial” modification may be installed in lieu of the “full” modification where the existing skin panels have no cracks, corrosion or repairs and have a thickness of 0.09" or less. The “partial” modification shall not be installed at deep countersink locations.
Note: FAA AD 94-12-09 refers.
Compliance: Effective 13 October 1994.
Background: Corrosion and corrosion induced cracking in the lap joints have been experienced on early model B747 aircraft.
Overview
The Civil Aviation Regulations 1998, specifically under Part 39 - 105, introduced Airworthiness Directives to address the safety concerns related to corrosion and corrosion-induced cracking in the fuselage upper lobe skin panel joints of Boeing 747 series aircraft. Enacted by the Australian Parliament, the policy objective of these directives is to ensure that such aircraft maintain airworthiness by mandating regular inspections and modifications to prevent structural failures. The regulations apply to Boeing 747 aircraft within specific line positions and outline the required inspections, the frequency of these inspections, and the necessary actions if corrosion or cracks are found. Compliance with these directives is mandatory and became effective from 13 October 1994, aiming to mitigate the risk of in-flight structural failure due to corrosion.
Scope and Application
The Civil Aviation Regulations 1998, specifically Part 39 - 105, govern the airworthiness directives for Boeing 747 series aeroplanes, ensuring the safety of these aircraft within Australian airspace and for Australian operators. This legislative instrument applies to Boeing 747 series aircraft line positions 001 to 200 inclusive. It mandates a series of inspections and modifications to address corrosion and cracking in the upper lobe skin panel lap joints, critical for maintaining the structural integrity of these aircraft. The regulations require detailed inspections at specific flight intervals, followed by modifications if corrosion or cracks are detected, and stipulate different inspection intervals based on the severity of the findings. Compliance with these directives is essential for continued operation of affected aircraft, with the requirement that inspections and modifications be carried out according to the specified Boeing Service Bulletin. These directives do not extend to aircraft outside the specified line positions or those that have already undergone the required modifications.
Key Provisions
The Civil Aviation Regulations 1998, specifically under Part 39 - 105 Civil Aviation Safety Authority Schedule of Airworthiness Directives for Boeing 747 series aeroplanes, set out detailed requirements for inspecting and maintaining the upper lobe skin panel joints of these aircraft (AD/B747/132). The regulation applies to Boeing 747 aircraft within line positions 001 to 200 inclusive. The key provisions include detailed inspections for corrosion and cracking at specified intervals and the installation of modifications to address identified issues. Initially, a detailed external visual inspection is required within 1000 flights after 13 October 1994, and this must be repeated at intervals not exceeding 2000 flights. Additionally, HFEC inspections are mandated to detect cracks in specific areas of the skin panel lap joints, with varying intervals for repetition based on the specific area being inspected.
The obligations under this Act include the necessity for operators of Boeing 747 aircraft to perform the specified inspections and modifications in a timely manner. Operators must ensure that the upper lobe skin panel joints are inspected for corrosion and cracking and that any identified issues are addressed according to the outlined procedures. The regulation stipulates that if corrosion is found but does not exceed 10% of the skin thickness, HFEC inspections must be performed at reduced intervals, and the “full” modification must be installed within 36 months. For more severe issues, such as cracks or corrosion exceeding 10% of the thickness, repairs must be made before further flight, and the “full” modification must be installed within 18 months. Moreover, the “full” modification must be installed before 20000 flights or within 1000 flights from 13 October 1994, whichever is later, at specified locations on the aircraft.
Failure to comply with these requirements can result in significant penalties and consequences. The Civil Aviation Regulations 1998 outline that non-compliance with airworthiness directives can lead to enforcement actions by the Civil Aviation Safety Authority. The maximum penalties for such breaches may include fines and potential grounding of the aircraft until the issues are resolved. Operators found in breach of these provisions may face both civil and criminal liabilities, depending on the severity and intent of the non-compliance. The precise penalties are not detailed in the provided text but are likely to be substantial, reflecting the critical nature of ensuring the airworthiness of commercial aircraft.