Airworthiness Directive · Amendment 39-18235 · Main rotor drive system
Bell Helicopter Textron Canada (Bell) Helicopters
This AD applies to Model 206L-4, 407, 427, and 429 helicopters with an engine-to-transmission driveshaft assembly (driveshaft), part number (P/N) 206-340-300-105, installed, certificated in any category.
We are superseding Airworthiness Directive (AD) 2001-13-51 for Bell Model 206L-4, 407, and 427 helicopters. AD 2001-13-51 required inspecting certain driveshafts for a crack, a loose bolt or nut, or red powder residue and replacing a driveshaft if there is a crack, a loose bolt or nut, or red powder residue. AD 2001-13-51 also required notifying the FAA within 10 days if a crack is found in the driveshaft. This new AD retains the inspection requirement of AD 2001-13-51, expands the applicability to include the Model 429 helicopter, and removes the reporting requirement. This AD is intended to prevent failure of a driveshaft, loss of drive to the main rotor system, and a subsequent emergency landing.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
(1) Within 50 hours time-in-service (TIS), determine whether driveshaft, P/N 206-340-300-105, has ever been installed on a Bell Model 407 helicopter, and record this on the component history card or equivalent record. If driveshaft, P/N 206-340-300-105, has ever been installed on a Bell Model 407 helicopter:
(i) For Bell Model 206L-4, 407, and 427 helicopters, within 25 hours TIS, inspect each driveshaft for a crack, a loose bolt or nut, and red powder residue. If there is a crack, a loose bolt or nut, or red powder residue, replace the driveshaft with an airworthy driveshaft before further flight.
(ii) For all affected Bell model helicopters, on or before accumulating 1,250 hours TIS, replace each driveshaft with an airworthy driveshaft.
(2) Do not install driveshaft, P/N 206-340-300-105, on any helicopter if it has ever been installed on a Bell Model 407 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.
