AD 68-04-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Bell Helicopter Textron Canada Limited | 206A | Airworthiness Directives; Bell Model 206A Helicopters |
Unsafe Condition
Failure of the exhaust stack clamps which attach the exhaust ducts to the engine exhaust flanges could cause hazardous damage to the main rotor or the tail rotor.
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Required Actions
Replace exhaust stack clamps P/N N3657 with National Utilities Corporation P/N 4656AA. Install new clamps with studs facing outboard, tighten nuts evenly to 30 inch-pounds, and safety wire nuts using P/N MS20995C32. Repeat torque checks until torque is maintained at 30 inch-pounds after shaking the stack and tapping the clamp with a plastic mallet.
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Compliance Time
within the next 25 hours time in service after the effective date of this Airworthiness Directive
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Affected Aircraft
Bell Helicopter Textron Canada Limited Model 206A Helicopters, Serial Numbers 4 through 110, 112 through 116, 118, 119, 122, 124 through 126, 128, 129 and 133.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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