The limitations contained in this DirectThe limitations contained in this Directive supersede any conflicting basic Aircraft Flight Manual limitations.

The limitations contained in this Directive supersede any conflicting basic Aircraft Flight Manual limitations.

Accomplishment of Requirement 2 of AD/B747/280 is acceptable for compliance with the requirements this Directive. This Directive does not require that those actions be repeated unless the terminating actions specified in Requirements 4, 6 and 7 of AD/B747/280 have been accomplished.

Accomplishment of the terminating actions specified in Requirement 4, 6 and 7 of AD/B747/280, does not allow removal of the AFM revisions required by this Directive.

Note: FAA Emergency AD 2002-24-51 and AD2002-24-52 refer.

Compliance: Before 29 November 2002.

This Airworthiness Directive becomes effective on 26 November 2002.

Background: The United States Federal Aviation Administration has received reports indicating that two fuel tank pumps from different Model 747 series aeroplanes showed evidence of extreme localized overheating of parts in the priming and vapour pump section of the fuel pump. The priming and vapour pump section of the pump is open to the fuel tank via the pump inlet line and the vapour vent of the pump. The cause of this overheating is believed to be friction between the pump parts; however, the specific cause of the friction is unknown at this time.

Overheating of the parts in the priming and vapour pump section of the fuel pump provides an ignition source in the fuel tank during dry running of the pump, which could result in fire/explosion of the fuel tank.