Airworthiness Directive · Amendment 39-13023 · Bell Helicopter Textron Canada Limited Model 407 Helicopters
Bell Helicopter Textron Canada Limited Model 407 Helicopters
Model 407 helicopters, serial numbers (S/N) 53000 through 53475, with tailboom assemblies, part numbers (P/Ns) 407- 030-801-105 or -107, or 407-530-014-103, having S/N 53390 through 53440, 53449, BP921, BP1014, and tail rotor gearbox support casting (casting), part number (P/N) 406-030-121-105, having S/N 980867/01- 2, 980867/01-3, 980867/01-4, 980867/01-5, 980867/01-8, 980867/01-9, and 980867/01-10, installed, certificated in any category.
This amendment adopts a new airworthiness directive (AD) for Bell Helicopter Textron Canada Limited (Bell) Model 407 helicopters. This action requires visually inspecting certain tailboom gearbox support castings (castings) for cracks and replacing the tailboom assembly if a crack is found. This amendment is prompted by an incident in which a crack was discovered on the casting that holds the tail rotor gearbox and vertical fin. The actions specified in this AD are intended to detect a crack in the casting and prevent failure of the casting, loss of the vertical fin and tail rotor, 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.
