Airworthiness Directive · Amendment 39-12449 · Bell Helicopter Textron Canada Model 206L-4 Helicopters
Bell Helicopter Textron Canada Model 206L-4 Helicopters
Model 206L-4 helicopters, with High Altitude Tail Rotor Kit, part number (P/N) 206-704-722-101 (BHT-206-SI-2054), installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for Bell Helicopter Textron Canada (BHTC) Model 206L-4 helicopters that requires installing a high altitude tail rotor static stop yield indicator (indicator) to allow operators to detect excessive bending loads sustained by the tail rotor yoke. A preflight check of the indicator is also required. This amendment is prompted by a determination that a tail rotor yoke with a high altitude rotor system is susceptible to a static and dynamic overload. Static overload could occur after the tail rotor yoke sustains an excessive bending load due to a strike from a ground vehicle. Dynamic overload could occur as a result of a hard landing. The actions specified by this AD are intended to prevent failure of the tail rotor yoke in flight and subsequent loss of control of the helicopter.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
