Airworthiness Directives; McDonnell Douglas Helicopter Systems Model MD-900 Helicopters

This amendment adopts a new airworthiness directive (AD) that is applicable to McDonnell Douglas Helicopter Systems (MDHS) Model MD- 900 helicopters. This action requires applying specified serial numbers to the left and right vertical stabilizer control system (VSCS) bellcrank assemblies, the forward and aft deck-fitting assemblies, and the mid-forward and mid-aft truss strut assemblies; and establishes new life limits for the non-rotating swashplate assembly, the collective drive link assembly, and the self-aligning, spherical/slider main rotor bearing. This amendment is prompted by additional manufacturer's analysis which indicates a need for the reduction of the life limit on several parts and the addition of non-serialized parts to the life- limited parts list. The actions specified in this AD are intended to establish a life limit for various parts and reduce the current life limit on other parts.