A-77-040
NTSB Safety Recommendation — Aviation
Recommendation text
ISSUE AN OPERATIONS BULLETIN TO ALL OPERATORS OF BELL 212 HELICOPTERS AND ALL OTHER BELL MODELS WITH P/N'S 204-040-620-3 OR 204-040-620-5 TAIL ROTOR DRIVE SHAFTS INSTALLED WARNING THEM TO USE CAUTION WHEN OPERATING IN FLIGHT REGIMES CONDUCIVE TO MAIN ROTOR OVERSPEED, PARTICULARLY ENGINE OPERATIONS INVOLVING "MANUAL" FUEL GOVERNING, SINCE THE TAIL ROTOR DRIVE SHAFT MAY FAIL IF A MAIN ROTORSPEED OF 115 PERCENT IS APPROACHED. (URGENT)
In plain language (FlightFinder summary)
The FAA was urged to alert pilots of specific Bell helicopter models about a risk of tail rotor drive shaft failure when main rotor speeds reach 115 percent. This warning specifically targeted operations involving manual fuel control, which can lead to dangerous overspeed conditions. The goal was to ensure operators exercised caution during flight phases where such high speeds might occur.
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 | Jan 5, 1978 |
| NTSB number | DEN77FA005 |
| Addressees | FAA |
External links
NTSB safety recommendations are advisory; addressees are not legally required to adopt them. Source: NTSB CAROL (public domain).