Inflight Engine Shutdowns Prompt Immediate Inspections of Boeing 777 Backup Engine Generators

FAA last week ordered Boeing 777-200 and -300 operators to inspect backup generators and replace any found with sheared shafts within 14 days.

The AD was prompted by two recent reports of inflight engine shutdowns caused by a failed engine backup generator. FAA says it is investigating the cause of the failures, including an examination of maintenance practices.

This "immediately adopted" airworthiness directive, effective Dec. 23, affects 61 B777 aircraft in the United States operated by American Airlines, Continental Airlines, Delta Air Lines, and United Airlines. All engine types are included in this AD, including PW4000, GE90 and Rolls Royce Trent 800 engines.

Under requirements of the AD, operators must:

• revise airplane flight manuals to prohibit 777 airplanes with sheared shafts from flying;
• inspect all backup generators and replace any with a sheared shaft. If both left and right backup generators are replaced at the same time, the operator must perform a non-ETOPS flight before resuming ETOPS operations; and
• prohibit servicing of both left and right backup generators by the same person.

Click here for the complete text of the AD.

For more information, contact Ed Hormel, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Transport Airplane Directorate, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 425-227-2681; fax 425-227-1181.

Edited by David Robb