Airworthiness Directive · Amendment 39-12935 · Bell Helicopter Textron Canada Limited Model 407 Helicopters
Bell Helicopter Textron Canada Limited Model 407 Helicopters
Model 407 helicopters, serial number (S/N) 53000 through 53498 and 53500 through 53512, certificated in any category.
This amendment supersedes an existing airworthiness directive (AD) for Bell Helicopter Textron Canada Limited (BHTCL) Model 407 helicopters that requires visually inspecting the brackets that attach the horizontal stabilizer slat (slat) to the stabilizer for a crack. If a crack is found, that AD also requires replacing the slat assembly before further flight. Also, that AD requires installing airworthy, segmented slat assemblies by a specified date. Installing segmented slat assemblies was considered terminating action for the requirements of that AD. This amendment requires, initially and at certain time intervals, checking each slat assembly for a cracked bracket and, if a crack is found, replacing any unairworthy slat assembly with an improved, airworthy slat assembly. This amendment also requires replacing, modifying, and installing identification plates on slats on certain helicopters at specified time intervals. This amendment is prompted by two additional reports of cracked brackets. The actions specified by this AD are intended to prevent a slat from separating, contacting a rotor blade, and resulting in 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.
