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 767 Series Aeroplanes

AD/B767/173 Thrust Reverser Directional Pilot Valve 7/2002

DM

Applicability: Model 767 series aeroplanes with General Electric CF6-80C2 series engines.

Requirement: 1. (a) For aeroplanes not modified in accordance with Boeing Service Bulletin (SB) 767-78-0063 or production equivalent carry out and successfully accomplish a functional test of the Directional Pilot Valve (DPV) of the thrust reversers to detect pneumatic leakage in accordance with Boeing Alert SB 767-78-0084 dated 21 October 1999.

(b) For aeroplanes modified in accordance with Boeing SB 767-78-0063 or production equivalent carry out and successfully accomplish a functional test of the DPV of the thrust reversers to detect pneumatic leakage in accordance with Boeing Alert SB 767-78-0084 dated 21 October 1999.

2.                  Repeat and successfully accomplish a functiona l test of Requirement 1(a).

3.                  Repeat and successfully accomplish a functional test of Requirement 1(b).

4.                  If any functional test required by Requirement 1, 2 or 3 of this Directive cannot be successfully carried out in accordance with the reference service bulletin, or if any discrepancy is detected during any functional test, repair in accordance with the Aircraft Maintenance Manual.

5.                  Repeat Requirement 1 functional tests if any discrepancies have been corrected under Requirement 4 during compliance with requirement 1, 2 or 3.

Production Equivalent

Functional tests accomplished in accordance with a production equivalent for aeroplanes modified during production, are acceptable as equivalent to the initial functional test required by Requirement 1(b) of this Directive. Therefore, in this case, compliance with Requirement 1(b) is not necessary.

Note: FAA AD 2000-17-06 Amdt 39-11880 refers.

Boeing 767 Series Aeroplanes

AD/B767/173 (continued)

Compliance: For Requirement 1: (a) Within 30 days after the effective date of this Directive.

(b) With the exception of aeroplanes modified and functionally tested in accordance with a production equivalent, within 60 days after the effective date of this Directive.

For Requirement 2: At intervals not exceeding 1,000 flight hours. For Requirement 3: At intervals not exceeding 6,000 flight hours. For Requirement 4: Prior to further flight.

For Requirement 5: Prior to further flight.

This Airworthiness Directive becomes effective on 5 June 2002.

Background: A possible leakage of the thrust reverser Directional Pilot Valve (DPV), due to a poppet valve being slightly jammed open or a leaking o-ring, has been identified by a report to the FAA as a latent failure of the fail-safe features of the thrust reverser system. The actions specified in this Directive are intended to ensure the integrity of the fail-safe features by preventing possible failure modes that could result in inadvertent deployment of the thrust reverser in- flight.

James Coyne

Delegate of the Civil Aviation Safety Authority 28 May 2002

The above AD is notified in the Commonwealth of Australia Gazette on 5 June 2002.