A-67-003
NTSB Safety Recommendation — Aviation
Recommendation text
IT IS RECOMMENDED THAT ALL USERS OF CONVAIR 340, 440 AND 580 MODELS BE ALERTED TO THIS VARIATION IN ELECTRICAL COCKPIT HEATERS, THAT THE TERMINALS BE PROMINENTLY IDENTIFIED AND MANUAL INSTRUCTIONS CITE THE DIFFERENT TERMINAL CONFIGURATIONS WITH APPROPRIATE INSTALLATION INSTRUCTIONS. IT IS RECOMMENDED THAT THE CONVAIR 340, 440 AND 580 AIRCRAFT HEATER CIRCUITS BE MODIFIED TO PROVIDE CIRCUIT PROTECTION THAT WILL OPEN UNDER THE MOST ADVERSE FAULT CONDITION BEFORE THE FEEDER LIMITER OPENS. DURING THE INVESTIGATION, TWO MAINTENANCE ITEMS WERE NOTED WHICH WE BELIEVE ARE WORTHY OF YOUR ATTENTION. WHILE EXAMINING THE AIRCRAFT, LOOSE NUTS, SCREWS, DRILL SHAVINGS AND TRASH WERE FOUND INSIDE OF THE CIRCUIT BREAKER PANEL COMPARTMENT. ALSO, IT WAS REVEALED THAT NO FUNCTIONAL TESTS WERE PERFORMED ON THE HEATER AFTER ITS INSTALLATION BEFORE RELEASING THE AIRCRAFT FOR PASSENGER SERVICE.
In plain language (FlightFinder summary)
The FAA is urged to ensure that operators of Convair 340, 440, and 580 aircraft clearly identify heater terminals and provide updated manuals explaining their different configurations. The agency should also require modifications to the heating circuits so that safety devices activate during faults before the main power limiters do. Additionally, the FAA needs to address maintenance oversights by preventing debris from entering breaker panels and mandating functional tests of heaters before planes return to service.
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 | NYC67A0089 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).