AD FAA-2017-1101

We are adopting a new airworthiness directive (AD) for certain ATR-GIE Avions de Transport R[eacute]gional Model ATR42-500 and ATR72- 212A airplanes. This AD requires revising the airplane flight manual to provide procedures to the flightcrew for operational restrictions affecting in-flight use of the autopilot (AP) or yaw damper (YD) during single source operation. This AD was prompted by flight test evaluations that revealed discrepancies with the YD and AP when in single source operation on certain airplanes. We are issuing this AD to address the unsafe condition on these products.