Commonwealth legislation

AD/B747/249 - Engine Thrust Control Cables

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Jurisdiction

Commonwealth

Collection

legislative instrument

Plain English Summary

4/10 complexity

This Airworthiness Directive requires operators of certain Boeing 747‑100/200/300 aeroplanes with a stretched upper deck and specific engine/angle‑assembly combinations to inspect and measure the clearance where engine thrust‑control cables pass through a plate. If clearance or cable wear fails the specified criteria, operators must modify the penetration holes or replace the plate and inspect or replace cables. Compliance is mandated within 12 months or before further flight where insufficient clearance exists. The measure aims to prevent cable chafing and failure that could cause asymmetric thrust.

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AD/B747/249 - Engine Thrust Control Cables

View image in the official source

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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.

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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.

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.

Signature of Eugene Paul Holzapfel, Delegate of the Civil Aviation Safety Authority.

Eugene Paul Holzapfel

Delegate of the Civil Aviation Safety Authority 1 June 2001

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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)

Boeing 747 Series Aeroplanes - Engine Thrust Control Cables.

Figure 1

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/B747/249 - Engine Thrust Control Cables

AIRWORTHINESS DIRECTIVE

Boeing 747 Series Aeroplanes

AD/B747/249 Engine Thrust Control Cables 7/2001

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.