A-91-085
NTSB Safety Recommendation — Aviation
Recommendation text
THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: REQUIRE THE GARRETT AUXILIARY POWER DIVISION TO IDENTIFY THOSE P/N 977156-1 APU HIGH-PRESSURE TURBINE (HPT) DISKS MANUFACTURED FROM THE 1974 TELEDYNE ALLVAC HEAT MELT THAT ARE MOST LIKELY TO CONTAIN ANOMALIES, SUCH AS LARGE FOREIGN MATERIAL INCLUSIONS THAT WOULD INITIATE FATIGUE CRACKS; ISSUE AN AIRWORTHINESS DIRECTIVE TO REQUIRE INSPECTION OF ALL SUSPECT DISKS FOR CRACKS IN ACCORDANCE WITH GARRETT ALERT SERVICE BULLETIN TSCP700-49-A6581 AND REMOVE FROM SERVICE OF ANY DISK FOUND TO CONTAIN DEFECTS.
In plain language (FlightFinder summary)
The Federal Aviation Administration must direct the Garrett Auxiliary Power Division to pinpoint which P/N 977156-1 APU high-pressure turbine disks were made from a 1974 Teledyne Allvac heat melt that may contain large foreign material inclusions, which could start fatigue cracks. Additionally, the FAA must issue an airworthiness directive mandating inspection of all suspect disks for cracks following Garrett Alert Service Bulletin TSCP700-49-A6581 and removal of any disk found with defects.
This plain-language summary is written by FlightFinder to explain the recommendation above. It is not the official wording — the verbatim NTSB text is quoted above.
Details
| Status | Closed - Acceptable Alternate Action |
|---|---|
| Mode | Aviation |
| Closed | Apr 22, 1994 |
| NTSB number | DCA91WA034 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).