AD 99-17-19
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bell Helicopter Textron Canada Limited | 206L | Airworthiness Directives; Bell Helicopter Textron, A Division of Textron Canada, Model 206L, L-1, L-3, and L-4 Helicopters |
| aircraft | Bell Helicopter Textron Canada Limited | 206L-1 | Airworthiness Directives; Bell Helicopter Textron, A Division of Textron Canada, Model 206L, L-1, L-3, and L-4 Helicopters |
| aircraft | Bell Helicopter Textron Canada Limited | 206L-3 | Airworthiness Directives; Bell Helicopter Textron, A Division of Textron Canada, Model 206L, L-1, L-3, and L-4 Helicopters |
| aircraft | Bell Helicopter Textron Canada Limited | 206L-4 | Airworthiness Directives; Bell Helicopter Textron, A Division of Textron Canada, Model 206L, L-1, L-3, and L-4 Helicopters |
Unsafe Condition
Fatigue failure of the mast or trunnion, which could result in loss of the main rotor system 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
Create a component history card or equivalent record for the affected mast and trunnion. Determine and record the accumulated Retirement Index Number (RIN) based on torque events using specified service bulletin. Increase the RIN daily for each torque event per model-specific multipliers (1 or 2 per event) and retire components when RIN reaches 24,000 (trunnion) or 44,000 (mast) or flight hour limit.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
within 100 hours time-in-service
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Bell Helicopter Textron, A Division of Textron Canada Model 206L, 206L-1, 206L-3, and 206L-4 helicopters with main rotor mast part numbers 206-040-535-001, -005, -101, or -105, or main rotor trunnion part number 206-011-120-103 installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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