Airworthiness Directives; Eurocopter France Model SE.3160, SA.315B, SA.316B, SA.316C, and SA.319B Helicopters

This amendment adopts a new airworthiness directive (AD) applicable to Eurocopter France Model SE.3160, SA.315B, SA.316B, SA.316C, and SA.319B helicopters with a main gearbox (MGB), all part numbers, not modified in accordance with MOD 072241. This action requires, prior to further flight and thereafter prior to the first flight of each day, inspecting the MGB magnetic plug for metal particles. This AD also requires inspecting the MGB oil filter for metal particles. This amendment is prompted by the failure of a bevel wheel gear attachment bolt (bolt) during testing of an SA.315B MGB. The actions specified in this AD are intended to detect a condition that could cause bolt failure and damage to the MGB, resulting in loss of drive to the main rotor and subsequent loss of control of the helicopter.