65-04-01 BELL: Amdt. 39-36 Part 39 Federal Register February 17, 1965. Applies to Model 47 Series Helicopters Equipped With Transmissions Serial Numbers B12-885 through B12-969.
Compliance required within 25 hours' time in service after the effective date of this AD, unless previously accomplished in accordance with Bell Helicopter Company Service Bulletin No. 141SB.
Some of the P/N 47-620-535-1 outer races installed in the freewheeling clutch of transmissions listed herein may not have been tempered properly. To eliminate the possibility of excessive wear of these races and subsequent malfunction of the freewheeling clutch, conduct a hardness test on these races as described by Bell Service Bulletin No. 141SB. If the hardness does not fall within the limits prescribed by the bulletin, replace the outer race with one which is within the limits before further flight.
This directive effective February 17, 1965.