Airworthiness Directive · Amendment 39-23209 · Main rotor drive system
Bell Textron Canada Limited Helicopters
This AD applies to Bell Textron Canada Limited Model 427 helicopters, serial numbers 56001 through 56084 inclusive, 58001, and 58002, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for certain Bell Textron Canada Limited (Bell) Model 427 helicopters. This AD was prompted by a report of a cracked transmission oil check valve (check valve). This AD requires inspecting and measuring certain check valves and, depending on the results, repetitively inspecting and removing the check valve from service if it has leaks or is cracked. This AD also prohibits installing the affected check valves on any helicopter. The FAA is issuing this AD to address the unsafe condition on these products.
Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, Transport Canada AD CF-2024-42, dated December 13, 2024 (Transport Canada AD CF-2024-42).
(1) Where Transport Canada AD CF-2024-42 refers to its effective date, this AD requires using the effective date of this AD.
(2) Where Transport Canada AD CF-2024-42 refers to air time, this AD requires using hours time-in-service.
(3) Where Parts I and II of Transport Canada AD CF-2024-42 state “new,” this AD requires replacing each instance of that text with “new (zero hours time-in-service)”.
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.
