Airworthiness Directives; Eurocopter France Model AS355E, F, F1, F2, and N Helicopters

Riepilogo

This amendment supersedes an existing airworthiness directive (AD) for the specified Eurocopter France (Eurocopter) model helicopters. That AD currently requires certain checks of the magnetic chip detector plug (chip detector) and the main gearbox (MGB) oil-sight glass, certain inspections of the lubrication pump (pump), and replacing the MGB and the pump with an airworthy MGB and pump, if necessary. Also, the AD requires that before a pump or MGB with any hours time-in-service (TIS) can be installed, it must meet the AD requirements. This AD adds all serial-numbered pumps to the applicability and requires using an improved procedure for detecting oil pump wear. This amendment is prompted by additional cases of MGB lubrication pump deterioration and a further investigation that determined that all serial-numbered pumps might be affected and the development of an improved procedure that is more accurate for detecting oil pump wear earlier. The actions specified by this AD are intended to implement improved procedures to detect a failing MGB oil pump, prevent failure of the MGB pump, seizure of the MGB, loss of drive to an engine and main rotor, and subsequent loss of control of the