AD 68-09-01
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| engine | Pratt & Whitney Division | Military R-985 Series | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. A | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. B-4 | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. B-5 | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. SB | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. SB-2 | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. SB-3 | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. T1B | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. T1B2 | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
| engine | Pratt & Whitney Division | Wasp Jr. T1B3 | PRATT & WHITNEY AIRCRAFT Model Wasp, Jr. and R-985 Type Engines |
Unsafe Condition
Excessive wear of the engine crankshaft flyweight and flyweight liners causing further propeller blade failures.
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Required Actions
Replace engine crankshaft flyweight liners P/N 34461; inspect and rework or replace engine crankshaft flyweights P/N 34462 and 34463 per Pratt & Whitney Service Bulletin 1758 Rev A or later FAA-approved revision. Compliance intervals depend on propeller model and time since last overhaul.
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Compliance Time
Within 50 hours' time in service after the effective date (January 17, 1973) and thereafter at intervals not exceeding 1,200 or 1,600 hours' time in service from last engine overhaul, depending on propeller model and time since overhaul.
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Affected Aircraft
Pratt & Whitney Division Model Wasp Jr. (A, B-4, B-5, SB, SB-2, etc.) and R-985 Series engines operated with specific Hartzell propellers (HC-93Z30, HC-B3Z30, HC-B3W30) or other eligible propellers.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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