AD FAA-2013-0522

We are publishing a new airworthiness directive (AD) for Eurocopter France Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350C, AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters. This AD requires, before further flight, determining whether a single hydraulic main or tail rotor servo-control is installed on your helicopter. If a certain servo-control is installed, before the further flight, this AD requires replacing that servo-control. This AD was prompted by the discovery of excessive axial play detected on bearings installed on certain single hydraulic main and tail rotor servo-controls (servo-control). The excessive play could cause the distributor slide valve to jam in its sleeve. This condition could result in jamming the hydraulic flight controls, necessitating that the pilot cut off hydraulic power. This action would increase the pilot's workload, resulting in possible loss of helicopter control.