AD 2001-08-04
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Textron | Inc | Airworthiness Directives; Bell Helicopter Textron Inc. Model 205A-1, 205B, 212, 412, 412CF, and 412EP Helicopters |
| aircraft | Bell | Helicopter Textron Inc | Airworthiness Directives; Bell Helicopter Textron Inc. Model 205A-1, 205B, 212, 412, 412CF, and 412EP Helicopters |
Unsafe Condition
Failure of the actuator end locking washer, leading to the servo lower piston rotating inside the lower servo head assembly and unthreading from the rod end, causing loss of collective control and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the tab on the NAS513-6 locking washer on all applicable actuators for twisting or damage. Replace any twisted or damaged locking washer with an airworthy NAS1193K6C locking device before further flight. Replace all NAS513-6 locking washers with airworthy NAS1193K6C locking devices within 100 hours time-in-service or at the next actuator overhaul, whichever occurs first. Installing an airworthy NAS1193K6C locking device on all actuators constitutes terminating action.
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Compliance Time
Within 25 hours time-in-service for initial inspection, and within 100 hours time-in-service or at the next actuator overhaul for replacement of all locking washers.
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Affected Aircraft
Bell Helicopter Textron Inc. Model 205A-1, 205B, 212, 412, 412CF, and 412EP helicopters with specific actuators (P/N 41105950 with HR prefix up to 490, or P/N 41000470 with HR prefix up to 10010) installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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