Airworthiness Directive · Amendment 39-14091 · Eurocopter France Model AS355E, F, F1, F2, and N Helicopters
Eurocopter France Model AS355E, F, F1, F2, and N Helicopters
Model AS355E, F, F1, F2, and N helicopters with a pre-MOD 077212 combiner gearbox that has 10 or less hours time-in-service installed, certificated in any category.
This amendment supersedes an existing airworthiness directive (AD) for the specified Eurocopter France (ECF) model helicopters. That AD currently requires replacing certain main or combiner gearboxes with airworthy gearboxes. Further investigation has shown that the main gearbox is not affected, and this amendment requires replacing a certain combiner gearbox with a modified airworthy gearbox. This amendment is prompted by a report of a freewheel unit slipping resulting in an engine overspeed and shutdown. Also, this amendment is prompted by the conclusion of the investigation, which finds the freewheel slippage is due to the surface treatment applied to certain freewheel rollers in the combiner gearbox. The actions specified by this AD are intended to prevent an engine overspeed, an engine shutdown, and subsequent loss of control of the helicopter.
To prevent an engine overspeed, an engine shutdown, and subsequent loss of control of the helicopter, accomplish the following:
(a) Before further flight, replace each pre-MOD 077212 combiner gearbox with a combiner gearbox modified by replacing the freewheel rollers in accordance with MOD 077212.
Note 1: Eurocopter France Alert Telex No. 63.00.21 R2, dated February 4, 2004, pertains to the subject AD.
(b) Performing paragraph (a) of this AD is terminating action for the requirements of this AD.
(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Safety Management Group, FAA, for information about previously approved alternative methods of compliance.
