AD 57-12-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Scotts-Bell 47 Inc | 47J | Airworthiness Directives; Bell Model 47J Helicopters |
Unsafe Condition
Failure of the engine sprag spindle P/N 47-612-167-1 due to overtorquing of the AN 320-10 nut.
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Required Actions
Remove spindle and links, install AN 6-17 bolt with AN 960-616L washer, drill No. 52 hole in AN 320-10 nut for safety wire, torque nut to 150 inch-pounds, install AN 960-616L washer and AN 310-6 nut with cotter key, and reconnect links with original hardware.
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Compliance Time
prior to July 1, 1957
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Affected Aircraft
Bell Model 47J Helicopters with serial numbers 1420 Through 1426, 1429 Through 1433, 1435 Through 1439, and 1441, 1559, 1562, 1574.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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