A-75-009
NTSB Safety Recommendation — Aviation
Recommendation text
ISSUE AN AIRWORTHINESS DIRECTIVE TO REQUIRE THAT A MAGNETIC CHIP DETECTOR BE INSTALLED IN ACCORDANCE WITH UACL SERVICE BULLETIN NO. 1217 AS A REPLACEMENT FOR THE REDUCTION GEARBOX DRAIN PLUG. WHEN THEMAGNETIC CHIP DETECTOR HAS BEEN INSTALLED, REQUIRE THAT THE DETECTOR BE INSPECTED AT INTERVALS NOT TO EXCEED 25 HOURS AND THAT THE MAIN OIL FILTER BE INSPECTED AT INTERVALS NOT TO EXCEED 50 HOURS, UNTIL A SATISFACTORY SOLUTION TO CORRECT THE FAILURE OF THE BEARING-SLEEVE IS FOUND.
In plain language (FlightFinder summary)
The FAA was urged to mandate the installation of a magnetic chip detector in place of the standard drain plug for the reduction gearbox. This change requires checking the detector every 25 hours and the main oil filter every 50 hours to monitor for metal debris. These inspections are necessary until a permanent fix for the bearing-sleeve failure is identified.
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 | Oct 1, 1975 |
| NTSB number | CHI75AC034 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).