1AD/B747/187 - Centre Wing Fuel Tank Scavenge Pump

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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Boeing 747 Series Aeroplanes

AD/B747/187 Centre Wing Fuel Tank Scavenge Pump 10/98

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Applicability: Model 747 series aeroplanes line positions 001 through 971 inclusive.

Requirement: 1. Unless previously accomplished, perform a one time inspection to determine the part number (P/N) of the installed scavenge pump motor-impeller unit in accordance with Boeing Alert Service Bulletin (ASB) 747-28A2215 dated 14 May 1998. If the P/N is neither Boeing P/N 60B92403-5 nor Lear Romec P/N RR24680 no further action is required.

2. If the P/N is either Boeing P/N 60B92403-5 or Lear Romec P/N RR24680 either:

Replace the scavenge pump with a new or serviceable pump having P/N 60B92403-12, \-13 or \-18 (Intertechnique); or with a new or serviceable pump having P/N 60B92403-51 (Lear Romec).

or

b. Deactivate the scavenge pump. The aeroplane may be operated with the scavenge pump deactivated in accordance with the provisions and limitations specified in the operator’s approved Master Minimum Equipment List.

Note: Boeing ASB 747-28A2215, refers to the 747 Dispatch Deviation Guide as another source for deactivation of the scavenge pump.

3. Scavenge pumps with either Boeing P/N 60B92403-5 or Lear Romec P/N RR24680 are not be installed on any aeroplane to replace an existing unit.

Note: FAA AD 98-14-17 Amdt 39-10650 refers.

Compliance: 1. Within 60 days after the effective date of this directive.

2. Before further flight after the Requirement 1 inspection.

3. As of the effective date of this directive.

This airworthiness directive becomes effective on 5 August 1998.

Background: This directive supersedes AD/B747/179 Amdt 1 (FAA AD 97-25-06) which is cancelled. The FAA has received a report of damage to the internal wiring of a scavenge pump that had its electrical connector replaced in accordance with FAA AD 97-25-06. Investigation revealed that the damage to the wiring was caused by the replacement connector’s longer backshell, which provided insufficient clearance for the attachment screw for the internal ground wire of the scavenge pump motor.

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 105 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

This directive requires the inspection to determine the part number of the installed scavenge pump motor-impeller and, if necessary, replacement of the scavenge pump. This action will decrease the likelihood of short circuiting and failure within the electrical motor assembly, such failures could result in leakage of fuel from the electrical connector into the main landing wheel well or electrical arcing with consequent risk of fire.