1 AD/B747/188 Amdt 3 - Centre Wing Fuel Tank Override/Jettison Inlet Check Valves
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AIRWORTHINESS DIRECTIVE
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For the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/B747/188 Amdt 2 and issues the following 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.
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Boeing 747 Series Aeroplanes
AD/B747/188
Amdt 3
Centre Wing Fuel Tank Override/Jettison Inlet Check Valves
4/2004
Applicability: All Model 747 series aeroplanes, line numbers 1 to 1251 inclusive, NOT fitted with centre wing fuel tank override/jettison fuel pumps that have been modified in accordance with Boeing Alert Service Bulletin 747-28A2212, Revision 3, dated 3 August, 2000.
Requirement: 1. Carry out a detailed inspection for wear or damage of the inlet check valve of the left and right override/jettison pumps of the centre wing fuel tank in accordance with Boeing Alert Service Bulletin (SB) 747-28A2212 Revision 3 and forward results to Boeing as indicated in the same SB page 17(3 F) and page 33 appendix A.
2. Carry out a detailed inspection for wear or damage of the inlet adapter of the left and right override/jettison pumps of the centre wing fuel tank in accordance with Boeing Alert Service Bulletin 747-28A2212 Revision 3 and forward results to Boeing as required by the same SB page 17(3 F) and page 33 appendix A.
3. Repeat the inspection requirements of 1 and 2 above; or
4. For aeroplanes that had accumulated 20,000 total flight hours time-in-service or more as of the effective date of amendment 1 of this Directive, amend the Limitations section of the FAA approved Aircraft Flight Manual (AFM) to include the following procedures:
“If the centre tank override/jettison fuel pumps are to be used, there must be at least 17,000 pounds (7,720 kilograms) of fuel in the centre tank prior to engine start. Do not operate the centre tank override/jettison fuel pumps with less than 7,000 pounds (3,200 kilograms) of fuel in the centre tank. For aeroplanes with an inoperative centre tank scavenge system, this 7,000 pounds of centre tank fuel must be considered unusable. If the centre tank override/jettison fuel pumps circuit breakers are tripped, do not reset”; or
5. Rework the existing pump housing and impeller motor assembly, including replacing the existing inlet check valve and inlet adapter in the centre wing fuel tank with new, improved parts; in accordance with Boeing Alert Service Bulletin 747-28A2212, Revision 3.
Note: 1. Requirement 4 of this Directive be accomplished by inserting a copy of this Directive into the AFM.
Note: 2. Boeing Alert Service Bulletin 747-28A2212, Revision 3, references Crane Hydro-Aire Service Bulletins 60-703-28-33, 60-703-28-35, 60-721-28-5, and 60-723- 28-5, as secondary sources of information for the rework of the pump housing and impeller motor assembly.
Note 3: FAA AD 2001-21-07 Amdt 39-12478 refers.
Compliance: For requirement 1 and 2: Remains unchanged as; Unless already accomplished, prior to further flight from the effective date of Amendment 2 of this Directive.
For requirement 3: Remains unchanged as; Upon the accumulation of 10,000 total flight hours in service or within 90 days after the effective date of Amendment 1 of this Directive: Every 1,000 or 10,000 flight hours dependent on the criteria specified in Boeing Alert Service Bulletin Boeing 747-28A2212, Revision 3 or earlier revisions.
For requirement 4: Unless already accomplished, or Requirements 1, 2 and 3 have not been complied with: Prior to further flight from the effective date of Amendment 2 of this Airworthiness Directive.
Note 4: Compliance with Requirements 1,2 and 3 is terminating action for this Requirement, therefore, the amendment to the AFM may be removed from the manual.
For requirement 5: Before 4 December 2008.
Compliance with this Requirement is terminating action for Requirements 1, 2 and 3 or 4 of this Airworthiness Directive and, as applicable, the amendment to the AFM at Requirement 4, may be removed from the manual.
This Amendment becomes effective on 15 April 2004.
Background: This amendment increases the compliance time for the rework and replacement of certain parts. The FAA has determined that extending the time for rework and replacement of parts will not introduce a safety concern.
Reports indicated that during inspection of a B747-400 fuel system, the inlet adapters of the override/jettison pumps of the centre wing fuel tank were worn. The adapters were sufficiently worn to cause damage to the rotating blades of the inducer. Inlet check valves also exhibited significant damage. FAA AD 2001-21-07 has now been issued and supersedes FAA AD 98-16-19, which was the subject of amendment 1 to this Directive. This Directive therefore reflects the latest FAA AD by introducing terminating action to the Aircraft Flight Manual amendment and/or repetitive inspections after rework and replacement of certain existing pump parts.
Amendment 2 of this Directive became effective on 3 April 2002.
Signature of James Coyne, Delegate of the Civil Aviation Safety Authority.
Amendment 1 of this Airworthiness Directive became effective on 21 October 1998 The original issue of this Airworthiness Directive became effective on 24 August 1998.
James Coyne
Delegate of the Civil Aviation Safety Authority 5 March 2004
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The above AD is notified in the Commonwealth of Australia Gazette on 24 March 2004.