Transport i lotnictwo · 24.07.1998

Airworthiness Directives; Boeing Model 747 Series Airplanes

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Boeing Model 747 series airplanes. This proposal would require a one-time inspection to detect discrepancies of the center fuel tank, and corrective actions, if necessary; replacement of all components of the fuel quantity indicating system (FQIS) of the center tanks with new FQIS components; and replacement of the FQIS wiring with new wiring. For certain airplanes, this proposal also would require a one-time inspection to detect discrepancies of the FQIS, and corrective actions, if necessary; and installation of a flame arrestor in the scavenge pumps of the center fuel tank. This proposal is prompted by design review and testing results obtained in support of an accident investigation. The actions specified by the proposed AD are intended to prevent ignition sources and consequent fire/explosion in the center fuel tank.