AIRWORTHINESS DIRECTIVE
For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.1 (1) of CAR 1998. The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.
Boeing 747 Series Aeroplanes
AD/B747/249 Engine Thrust Control Cables 7/2001
Applicability: Boeing Model 747-100, -200B, -200C, -200F and -300 series aeroplanes equipped with Pratt and Whitney Model JT9D-3 or –7 series engines, General Electric Model CF6-45 or –50 series engines, or Rolls-Royce Model RB 211-524 B, C or D series engines; delivered in or modified into stretched upper deck (SUD) configuration and having angle assemblies with Boeing part numbers 015U0454-63 and 015U0454-64 installed at body station 970.
Requirement: 1. Perform a detailed visual inspection and measure the clearance between the engine thrust control cables and the cable penetration holes in accordance with the Cable Chafing Inspection of the Accomplishment Instructions of Boeing Service Bulletin (SB) 747-53-2327, Revision 2. If the clearance is within the limits specified by the SB, no further action is required by this AD.
2. If, during compliance with Requirement 1, insufficient clearance as specified in SB 747-53-2327 Revision 2 exists, accomplish:
(a) Modify the cable penetration holes or replace the plate, as applicable, in accordance with Figure 7 of the SB, and
(b) Perform a detailed visual inspection of the engine thrust control cables in the area of the plate to detect wear and broken wires in accordance with Appendix A of this AD. If any wear outside the criteria contained in Appendix A of this AD is found, replace the cable with a new cable, in accordance with procedures described in the Boeing 747 Maintenance Manual. If wear is within the criteria contained in Appendix A of this AD, no further action is required by this paragraph.
Note: FAA AD 2000-12-15 Amendment 39-11962 refers
Compliance: 1. Unless already accomplished, within 12 months from the effective date of this Directive.
2. Unless already accomplished, prior to further flight if insufficient clearance exists as specified in the SB 747-53-2327 Revision 2, after the inspection as per Requirement 1.
Boeing 747 Series Aeroplanes
AD/B747/249 (Continued)
This Airworthiness Directive becomes effective on 12 July 2001.
Background: This Directive is issued to prevent chafing and failure of engine thrust control cables, which could result in severe asymmetric thrust conditions during landing, and consequent reduced controllability of the airplane.
Eugene Paul Holzapfel
Delegate of the Civil Aviation Safety Authority 1 June 2001
The above AD is notified in the Commonwealth of Australia Gazette on 13 June 2001.
Boeing 747 Series Aeroplanes
AD/B747/249
Appendix A
Engine Thrust Control Cables 7/2001
INSPECTION PROCEDURE
- Detailed Visual Inspection to Detect Wear
(a) Perform a detailed visual inspection of the engine thrust control cables in the area of the plate to detect wear.
(b) Replace the cable assembly if any of the following criteria are met:
(i) One cable strand had worn wires where one wire cross section is decreased by more than 40 percent (see Figure 1)
(ii) A kink is found
(iii) Corrosion is found.
2. Inspection to Detect Broken Wires
(a) To check for broken wires, rub a cloth along the length of the cable. The cloth catches on broken wires.
(b) Replace the cable assembly if any of the following criteria are met.
(i) Replace the 7x7 cable assembly if there are two or more broken wires anywhere in the total cable assembly.
(ii) Replace the 7x19 cable assembly if there are four or more broken wires in 12 continuous inches of cable or there are six or more broken wires anywhere in the total cable assembly.
COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Boeing 747 Series Aeroplanes
AD/B747/249 Appendix A (Continued)
Figure 1
Overview
The Civil Aviation Safety Authority (CASA) introduced the Airworthiness Directive (AD) Boeing 747 Series Aeroplanes AD/B747/249 in 2001 to address potential safety issues associated with the engine thrust control cables on certain Boeing 747 series aeroplanes. This AD was enacted under subregulation 39.1 (1) of the Civil Aviation Regulations 1998. The primary objective of this directive is to prevent chafing and failure of engine thrust control cables, which could lead to severe asymmetric thrust conditions during landing and consequently reduce the controllability of the aeroplane. CASA issued this directive to ensure that all applicable aircraft meet specific safety criteria, thereby enhancing overall aviation safety. Compliance with this AD is mandatory, requiring inspections and necessary modifications to be completed within specified timeframes to mitigate identified risks.
Scope and Application
This Airworthiness Directive applies to Boeing 747-100, -200B, -200C, -200F, and -300 series aeroplanes equipped with specified engine models and installed in the stretched upper deck (SUD) configuration, with certain angle assemblies. The AD mandates that detailed visual inspections and measurements of the clearance between the engine thrust control cables and the cable penetration holes be performed in accordance with Boeing Service Bulletin 747-53-2327, Revision 2. If the clearance is within specified limits, no further action is required. However, if insufficient clearance is detected, modifications to the cable penetration holes or replacement of the plate must be carried out, followed by a detailed visual inspection of the engine thrust control cables. If wear or broken wires are detected, the cables must be replaced. This AD must be complied with within 12 months from its effective date, or prior to further flight if insufficient clearance exists after the initial inspection. The directive is issued under the authority of the Civil Aviation Safety Authority to address potential chafing and failure of engine thrust control cables, which could lead to severe asymmetric thrust conditions during landing and reduced controllability of the aeroplane.
Key Provisions
The Airworthiness Directive (AD) issued under subregulation 39.1 (1) of the Civil Aviation Regulations 1998 (CAR 1998) sets out specific requirements for certain Boeing 747 aeroplanes. The directive, AD/B747/249, pertains to the engine thrust control cables for Boeing 747-100, -200B, -200C, -200F, and -300 series aeroplanes equipped with specific engine models and delivered or modified into a stretched upper deck (SUD) configuration with certain angle assemblies installed. The directive mandates that a detailed visual inspection of the clearance between the engine thrust control cables and the cable penetration holes be performed in accordance with the Cable Chafing Inspection outlined in Boeing Service Bulletin 747-53-2327, Revision 2 (Section 2.1). If the clearance is within specified limits, no further action is required. If the clearance is insufficient, modification or replacement of the plate and a detailed inspection of the engine thrust control cables for wear and broken wires are required, as per the SB and the AD's appendix (Section 2.2).
The directive imposes several obligations on the entities it governs. Operators of affected Boeing 747 aeroplanes must perform the specified visual inspections and measurements within the stipulated timeframes. Specifically, unless the required actions have already been completed, operators must perform the inspection and any necessary modifications within 12 months of the directive's effective date, and before further flight if insufficient clearance is found after the initial inspection (Section 3). Additionally, operators must follow the detailed inspection procedures for wear and broken wires as outlined in the directive and the Boeing 747 Maintenance Manual.
Failure to comply with the requirements of this Airworthiness Directive may result in serious safety implications, including potential chafing and failure of engine thrust control cables, leading to severe asymmetric thrust conditions and reduced controllability of the aeroplane during landing. Although the text does not explicitly state penalties for non-compliance, non-compliance with ADs generally can lead to severe consequences, including fines and potential grounding of the aircraft. The directive becomes effective on 12 July 2001, and its importance is underscored by the need to address the risk of cable chafing and failure to prevent potential safety hazards.