A-91-083
NTSB Safety Recommendation — Aviation
Recommendation text
THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: ISSUE AN AIRWORTHINESS DIRECTIVE APPLICABLE TO ALL BOEING 747 AIRPLANES WITH A FLEXIBLE CONDUIT PROTECTING THE WIRING BUNDLE BETWEEN THE FUSELAGE AND AFT CARGO DOOR TO REQUIRE AN EXPEDITED INSPECTION OF: 1) THE WIRING BUNDLE IN THE AREA NORMALLY COVERED BY THE CONDUIT FOR THE PRESENCE OF DAMAGED INSULATION (USING EITHER AN ELECTRICAL TEST METHOD OR VISUAL EXAMINATION); 2) THE CONDUIT SUPPORT BRACKET AND ATTACHED STANDOFF PIN ON THE UPPER ARM OF THE FORWARD LIFT ACTUATOR MECHANISM; 3) THE FLEXIBLE CONDUIT FOR THE PRESENCE OF CRACKING IN THE CONVOLUTED INNERCORE. WIRES WITH DAMAGED INSULATION SHOULD BE REPAIRED BEFORE FURTHER SERVICE. DAMAGE TO THE FLEXIBLE CONDUIT, CONDUIT SUPPORT BRACKET AND STANDOFF PIN SHOULD RESULT IN AN IMMEDIATE REPLACEMENT OF THE CONDUIT AS WELL AS THE DAMAGED PARTS. THE INSPECTION SHOULD BE REPEATED AT AN APPROPRIATE CYCLIC INTERVAL.
In plain language (FlightFinder summary)
The FAA is asked to issue an airworthiness directive for all Boeing 747 airplanes with a flexible conduit protecting the wiring bundle between the fuselage and aft cargo door. The directive would require an expedited inspection of the wiring bundle insulation (using electrical test or visual exam), the conduit support bracket and standoff pin on the forward lift actuator, and the flexible conduit for cracking. Damaged insulation must be repaired before further service, and damage to the conduit, bracket, or pin requires immediate replacement, with the inspection repeated at an appropriate cyclic interval.
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 - Reconsidered |
|---|---|
| Mode | Aviation |
| Closed | Nov 8, 1993 |
| NTSB number | DCA89MA027 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).