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. 4. If the valve does not pass the test, as detailed in Requirement 2 of this Directive, replace the valve with a serviceable valve, P/N S270T010-3, 10-3200- 1, 10- 3200-2, or a valve identified in paragraph 3.I. of the Accomplishment Instructions of Boeing ASB 747-29A2102; and do a hydraulic supply (fire) shutoff valve test; in accordance with paragraph 3.J. of the Accomplishment Instructions of Boeing ASB 747-29A2102. Replacement with a serviceable valve, P/N 10-3200-1, 10-3200-2, or a valve identified in paragraph 3.I. of the Accomplishment Instructions of Boeing ASB 747-29A2102, terminates the repetitive tests required by Requirement 3 of this Directive. If a P/N S270T010-3 valve is installed as a replacement, repeated testing must be performed in accordance with Requirement 3 of this Directive. Boeing 747 Series Aeroplanes AD/B747/301 (continued) 5. Replace each discrepant valve with a serviceable valve, P/N 10-3200-1, 10-3200- 2, or a valve identified in paragraph 3.I. of the Accomplishment Instructions of the service bulletin, and do a hydraulic supply (fire) shutoff valve test, in accordance with paragraph 3.J. of the Accomplishment Instructions of Boeing ASB 747-29A2102. Note: FAA AD 2003-26-13 Amdt 39-13412 refers. Compliance: For Requirement 1 and 2: Unless previously accomplished, within 6 months after the effective date of this Directive. For Requirement 3: At intervals not to exceed 6 months, until the actions specified by Requirement 5 of this Directive have been accomplished. For Requirement 4: Before further flight. For Requirement 5: Within 4 years from the time the discrepant valve is identified as detailed in Requirement 1 of this Directive. This Airworthiness Directive becomes effective on 15 April 2004. Background: This Directive requires identification of the valves installed on the engine struts as hydraulic supply (fire) shutoff valves for the engine-driven pump, repetitive tests if necessary, and eventual replacement of discrepant valves. This action is necessary to prevent leakage of hydraulic (flammable) fluid into an engine fire, which could result in an uncontrolled fire. This action is intended to address the identified unsafe condition. James Coyne Delegate of the Civil Aviation Safety Authority 4 March 2004 The above AD is notified in the Commonwealth of Australia Gazette on 24 March 2004.