Airworthiness Directive · Amendment 39-11125 · Boeing Model 747 Series Airplanes
Boeing Model 747 Series Airplanes
Model 747 series airplanes, line positions 001 through 1150 inclusive; equipped with an auxiliary power unit (APU) fuel boost pump manufactured by Lear Romec and having Lear Romec part number (P/N) RR24640B; certificated in any category.
This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This action requires replacement of the auxiliary power unit (APU) fuel boost pump with a serviceable pump. This amendment is prompted by findings from a design review and analysis, conducted as part of an accident investigation, of APU fuel boost pumps installed on certain Boeing Model 747 series airplanes. The actions specified in this AD are intended to prevent potential failures within the electrical motor assembly of the APU fuel boost pump (which could result in leakage of fuel from the electrical connector) or electrical arcing across the connector pins of the pump, and consequent fuel fire.
