A-98-111
NTSB Safety Recommendation — Aviation
Recommendation text
THE NTSB RECOMMENDS THAT THE FAA: ISSUE AN AIRWORTHINESS DIRECTIVE TO REQUIRE THAT DC-9 OPERATORS MODIFY ALL EXISTING WESTINGHOUSE PART NUMBER (P/N) 914F567-3 ALTERNATING CURRENT POWER RELAY (I.E. CROSS-TIE RELAYS, GENERATOR RELAYS, AUXILIARY POWER RELAYS, & EXTERNAL POWER RELAYS) TO THE -4 CONFIGURATION, IN ACCORDANCE WITH DOUGLAS AIRCRAFT COMPANY ALL OPERATORS LETTER 9-977, DATED 5/5/76, & OVERHAUL THE RELAYS EVERY 7,000 FLIGHT HOURS THEREAFTER OR REPLACE THESE RELAYS WITH THE IMPROVED POWER RELAY, P/N 9008D09.
In plain language (FlightFinder summary)
The NTSB urged the FAA to mandate that DC-9 operators upgrade specific electrical relays to a safer design or replace them entirely. This action was intended to address potential safety risks associated with the older relay models used in various power systems. Additionally, the recommendation required these updated components to be overhauled every 7,000 flight hours to maintain their reliability.
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 | Mar 11, 2003 |
| NTSB number | CHI97IA072 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).