Airworthiness Directive · Amendment 39-17857 · Main rotor system
Agusta S.p.A Helicopters (Type Certificate Currently Held by AgustaWestland S.p.A) (Agusta)
This AD applies to Agusta Model A109A, A109A II, A109C, A109E, A109K2, A109S, AW109SP, A119, and AW119 MKII helicopters with a nut, part-number (P/N) MS21042-4, connecting the main rotor swashplate support to the upper case of the main transmission installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Agusta Model A109A, A109A II, A109C, A109E, A109K2, A109S, AW109SP, A119, and AW119 MKII helicopters. This AD requires inspecting and replacing certain part-numbered main rotor swashplate support nuts. This AD is prompted by a report of two cracked nuts found on an A109S helicopter. These actions are intended to detect a cracked nut and prevent failure of the main rotor system, and subsequent loss of control of the helicopter.
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 10 hours time-in-service (TIS), using a light, visually inspect each nut, P/N MS21042-4, which connects the swashplate support to the upper case of the main transmission for a crack.
(i) If there is a crack, before further flight, remove all six nuts, P/N MS21042-4, connecting the swashplate support to the upper case.
(ii) If there are no cracks, within 25 hours TIS, remove all six nuts, P/N MS21042-4, connecting the swashplate support to the upper case.
(2) Do not install a nut, P/N MS21042-4, connecting the swashplate support to the upper case of the main transmission on any 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.
