Airworthiness Directive · Amendment 39-21699 · Tail rotor gearbox
Leonardo S.p.a. Helicopters
This AD applies to Leonardo S.p.a. Model AW189 helicopters, certificated in any category, with tail gearbox fitting part number (P/N) 4F5350A04152 installed.
The FAA is adopting a new airworthiness directive (AD) for certain Leonardo S.p.a. Model AW189 helicopters. This AD was prompted by fatigue testing and analyses. This AD requires establishing a life limit for a certain part-numbered tail gearbox fitting. The FAA is issuing this AD to address the unsafe condition on these products.
Before further flight after the effective date of this AD:
(1) Determine the total hours time-in-service (TIS) and total number of landings of tail gearbox fitting P/N 4F5350A04152. For purposes of this AD, a landing is counted anytime a helicopter lifts off into the air and then lands again regardless of the duration of the landing and regardless of whether the engine is shutdown. If the total hours TIS and total number of landings cannot be determined, before further flight, remove the part from service.
(2) Remove any part from service that has reached or exceeded its life limit as follows. Thereafter, remove any part from service on or before reaching its life limit as follows. Tail gearbox fitting P/N 4F5350A04152: 14,600 total hours TIS or 57,300 total landings, whichever occurs first.
