Airworthiness Directives; Eurocopter Deutschland GMBH Model EC 135 P1 and EC 135 T1 Helicopters

This amendment adopts a new airworthiness directive (AD) applicable to Eurocopter Deutschland GMBH (ECD) Model EC 135 P1 and EC 135 T1 helicopters. This action requires inspecting main rotor expansion bolt safety wires, bolt heads, and bolt nuts; replacing any unairworthy expansion bolt with a hexagon bolt; and, as necessary, replacing any bolt nut before further flight. This AD also requires replacing each expansion bolt, regardless of condition, no later than January 31, 2000. This amendment is prompted by reports of main rotor blade expansion bolt nuts becoming loose. This condition, if not corrected, could result in severe vibration during flight and subsequent loss of control of the helicopter.