AD FAA-2015-8426

We are adopting a new airworthiness directive (AD) for certain Dassault Aviation Model MYSTERE-FALCON 900 airplanes, FALCON 900EX airplanes, and FALCON 2000EX airplanes. This AD was prompted by a report that during a test flight, it was found that the yaw damper on the takeoff roll can increase the Minimum Control Speed on Ground (Vmcg). This AD requires revising the airplane flight manual (AFM) to incorporate procedures for the flightcrew to check that the yaw damper is set to "off" before takeoff. We are issuing this AD to ensure that the flightcrew has procedures to set the yaw damper to "off" before takeoff, which, if activated, could result in reduced control of the airplane if one engine were to fail during takeoff.