Transport i lotnictwo · 23/11/1998

Airworthiness Directives; Boeing Model 777 Series Airplanes

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 777 series airplanes. This proposal would require repetitive inspections of the safety spring wear plate doublers attached to the auxiliary power unit (APU) firewall, measurement of wear of the doublers, and follow-on actions, if necessary. This proposed AD also would provide for optional terminating action for the repetitive inspections. This proposal is prompted by reports indicating that excessive wear was found on the safety spring wear plate doublers on the APU firewall of Boeing Model 777 series airplanes. The actions specified by the proposed AD are intended to detect and correct wear of the safety spring wear plate doublers on the APU firewall, which could result in a hole in the APU firewall, and consequent decreased fire protection capability.