COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/137 Nacelle - Strut Diagonal Brace 5/95
Applicability: All B747 Line No 001 to 781 inclusive except aircraft with PW4000 and GE CF6-80 engines.
Requirement: Inspect the Diagonal Brace for cracks using a detailed visual or a combination of detailed visual and ultrasonic inspection methods. Inspect in accordance with Boeing SB 747-54-2123 Rev 2.
Note: FAA AD 90-20-20 refers.
Compliance: 1. Initially inspect before 10000 flights or within 1000 flights of 27 April 1995, whichever is the later.
2. Repeat the inspections at intervals not exceeding 1000 flights if only a detailed visual inspection is used. Repeat the inspections at intervals not exceeding 3000 flights if a combination of detailed visual and ultrasonic methods is used.
3. Replacement of the Diagonal Brace with a new production brace, which has a revised internal and external finish, cancels the inspection requirements of this AD.
Background: An operator has reported finding a severed diagonal brace. The failure originated at a 0.0025 deep machining mark. Inspection in accordance with this AD on similar production status braces will ensure crack detection before brace failure.
Overview
The Civil Aviation Regulations 1998, administered by the Civil Aviation Safety Authority, was enacted to provide comprehensive regulations to ensure the safety and efficiency of civil aviation in Australia. One specific aspect of these regulations is found in Part 39 - 105, which includes airworthiness directives aimed at maintaining the safety standards of aircraft. The Boeing 747 Series Aeroplanes AD/B747/137 pertains to the inspection of the nacelle strut diagonal brace to prevent potential failures that could compromise flight safety. This directive applies to all Boeing 747 aircraft from line numbers 001 to 781, excluding those equipped with PW4000 and GE CF6-80 engines. The policy objective is to ensure that the diagonal brace is inspected for cracks using detailed visual or a combination of visual and ultrasonic inspection methods, as specified by Boeing SB 747-54-2123 Rev 2, to avoid catastrophic failures that could arise from machining marks.
Scope and Application
The Civil Aviation Regulations 1998, as part of their schedule of airworthiness directives, specifically address the Boeing 747 Series aeroplanes through AD/B747/137 concerning the nacelle strut diagonal brace. This regulation applies to all Boeing 747 aircraft line numbers from 001 to 781, excluding those equipped with PW4000 and GE CF6-80 engines. The directive mandates that operators inspect the diagonal brace for cracks using either a detailed visual inspection or a combination of detailed visual and ultrasonic inspection methods, in accordance with Boeing Service Bulletin 747-54-2123 Revision 2. Compliance with this directive requires an initial inspection to be conducted before the aircraft accumulates 10,000 flights or within 1,000 flights of 27 April 1995, whichever is later. Following the initial inspection, operators must repeat the inspections at intervals not exceeding 1,000 flights if only a detailed visual inspection is used or at intervals not exceeding 3,000 flights if a combination of detailed visual and ultrasonic methods is used. This directive cancels the inspection requirements if the diagonal brace is replaced with a new production brace that has a revised internal and external finish. The directive references FAA AD 90-20-20, indicating alignment with international safety standards.
Key Provisions
The Civil Aviation Regulations 1998, specifically PART 39 - 105 (3), mandates inspections for the strut diagonal brace in Boeing 747 series aeroplanes to ensure safety. Section 5/95 requires operators to inspect the diagonal brace for cracks using either a detailed visual inspection or a combination of detailed visual and ultrasonic inspection methods. These inspections must follow Boeing Service Bulletin 747-54-2123 Rev 2 and reference FAA AD 90-20-20. The requirement applies to Boeing 747 aircraft from line numbers 001 to 781, excluding those equipped with PW4000 and GE CF6-80 engines.
Operators must adhere to specific compliance timelines and intervals for these inspections. The initial inspection must be conducted before the aircraft accumulates 10,000 flights or within 1000 flights of 27 April 1995, whichever occurs later. If only a detailed visual inspection is performed, subsequent inspections must take place at intervals not exceeding 1000 flights. If a combination of detailed visual and ultrasonic methods is used, inspections should occur at intervals not exceeding 3000 flights. If the diagonal brace is replaced with a new production brace featuring a revised internal and external finish, the inspection requirements are cancelled.
Failure to comply with the inspection requirements set forth in the AD/B747/137 may result in serious safety implications, as evidenced by a reported incident where a diagonal brace was found severed. Such non-compliance could lead to structural failure of the aircraft, potentially causing catastrophic outcomes. While the specific legal consequences for non-compliance are not detailed in the legislative instrument, general provisions under the Civil Aviation Act 1988 could apply, including potential penalties for breaches of safety regulations.