AD 2022-27-03 Retains The Requirements Of AD 2021-20-10 And Clarifies The Applicability
The FAA is superseding Airworthiness Directive (AD) 2021-20-10 for certain Leonardo S.p.a. Model AB139 and AW139 helicopters. AD 2021-20-10 required removing from service a certain part-numbered main gearbox (MGB) spherical bearing lock nut (lock nut) that is installed on certain part-numbered MGBs and replacing it with a newly designed MGB lock nut. AD 2021-20-10 also prohibited installing any MGB with the affected MGB lock nut and prohibited installing any affected MGB lock nut on any helicopter.
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