AD/B747/301 - Discrepant Hydraulic Valves (Cth)

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 CASR 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/B747/301 Discrepant Hydraulic Valves 4/2004

Applicability: Model 747 series aeroplanes, as listed in Boeing Alert Service Bulletin (ASB) 747- 29A2102, dated June 29, 2000.

Requirement: 1. Check maintenance records or perform a general visual inspection of each engine strut to determine whether any discrepant valve is installed as a hydraulic supply (fire) shutoff valve for the engine-driven pump. A discrepant valve is a Circle Seal valve part number (P/N) S270T010-3 or a valve that cannot be readily identified. Identify the part in accordance with Boeing ASB 747- 29A2102. If no discrepant valve is installed, no further action is required.

2. For any discrepant valve found during the part identification required by Requirement 1 of this Directive: Carry out a hydraulic supply (fire) shutoff valve test, in accordance with paragraph 3.J. of the Accomplishment Instructions of Boeing ASB 747-29A2102.

3. If the valve passes the test, as detailed in Requirement 2 of this Directive, repeat the test in accordance with paragraph 3.J. of the Accomplishment Instructions of Boeing ASB 747-29A2102.