A-67-022
NTSB Safety Recommendation — Aviation
Recommendation text
IT IS RECOMMENDED THAT A FIREPROOF BARRIER OF APPROPRIATE WIDTH BE PROVIDED AT THE FUSELAGE TOP SKIN BETWEEN FUSELAGE STATIONS 936 AND 958. ALSO, IT IS RECOMMENDED THAT THE ALUMINUM ALLOY WALL SEPARATING THE HYDRAULIC BAY AND THE APU AIR INTAKE PLENIUM CHAMBER BE REPLACED WITH SUITABLE FIREPROOF MATERIAL. AS OF THIS TIME WE HAVE NOT IDENTIFIED THE IGNITION SOURCE OF THE INFLIGHT FIRE; HOWEVER, ALL POSSIBLE SOURCES ARE BEING CONSIDERED. IN THIS CATEGORY, AN OBVIOUS POSSIBLE SOURCE OF HEAT AND FLAME IN THE FIRE AREA IS THE AUXILIARY POWER UNIT. ALTHOUGH OUR EVIDENCE DOES NOT POINT TO THE APU AS A SOURCE OF IGNITION, AS A PRECAUTIONARY MEASURE IT IS RECOMMENDED THAT, UNTIL SUCH TIME AS SUITABLE BARRIERS AS RECOMMENDED ABOVE ARE PROVIDED, INFLIGHT USE OF THE APU BE RESTRICTED.
In plain language (FlightFinder summary)
The FAA is advised to install fire-resistant barriers in specific areas of the aircraft fuselage and replace an existing aluminum wall with a material that can withstand high heat. These measures aim to prevent potential fires from spreading, particularly because the auxiliary power unit could serve as a source of ignition. Until these physical improvements are completed, the agency should limit the use of the auxiliary power unit during flight as a precautionary safety step.
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 Action |
|---|---|
| Mode | Aviation |
| Closed | Jan 1, 1975 |
| NTSB number | DCA67A0009 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).