AD FAA-2017-1177

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 (AFM) to provide procedures to the flight crew for operational restrictions affecting in-flight use of the autopilot (AP) or yaw damper (YD) during dual-engine operation. This AD also provides an optional software modification, which would terminate the AFM requirement. This AD was prompted by flight test evaluations that revealed that after engine failure during AP or YD re-engagement, the YD unit commanded the rudder to return to neutral position, leading to inadequate balancing of the asymmetric power. We are issuing this AD to address the unsafe condition on these products.