Airworthiness Directives; MD Helicopters, Inc., Model MD900 Helicopters

This amendment adopts a new airworthiness directive (AD) for MD Helicopters, Inc., Model MD900 helicopters that requires, for the lateral-mixer bellcrank assembly (bellcrank), establishing a life limit, creating a component history card or equivalent record, determining the hours time-in-service (TIS), and applying a serial number (S/N). This amendment is prompted by additional testing that revealed that the original load test to establish the life limits of the bellcrank did not accurately represent the actual loading. The actions specified by this AD are intended to prevent fatigue failure of the bellcrank and subsequent loss of lateral control of the helicopter.