AD 96-18-22 61 FR 53046 Active

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) 96-18-22 which was sent previously to all known U.S. owners and operators of Robinson Helicopter Company (Robinson) Model R44 helicopters by individual letters. This AD requires an inspection of the mating surfaces of the main rotor gearbox (gearbox) components for pitting, elongated bolt holes, or machining grooves, and replacement of the gearbox if elongated bolt holes, machining grooves, or an improper amount of pitting is discovered; and replacement of the 18 bolts and washers that attach the gear to the gear carrier assembly (gear carrier). This amendment is prompted by an inflight failure of the gearbox on a French-registered Model R44 helicopter that resulted in an accident. The actions specified by this AD are intended to prevent loosening of the bolts securing the gear to the gear carrier, which could lead to fatigue failure of the gear carrier within the gearbox, and subsequent loss of power to the main rotor which could lead to a forced landing.