Airworthiness Directives; Societe Nationale Industrielle Aerospatiale and Eurocopter France Model AS-355 E, F, F1, F2, and N Helicopters

This amendment adopts a new airworthiness directive (AD) that is applicable to Societe Nationale Industrielle Aerospatiale and Eurocopter France (Eurocopter France) Model AS-355 E, F, F1, F2, and N helicopters. This action requires a check to ensure that the main gearbox (MGB) oil pressure warning light illuminates during each shutdown of the helicopter engine until the MGB oil pressure switch (switch) is removed and replaced. This amendment is prompted by a malfunction of the MGB switch. This condition, if not corrected, could result in failure to detect a loss of oil pressure, loss of the MGB, loss of power to the main rotor system, and subsequent loss of control of the helicopter.