Airworthiness Directives; Dassault Model Mystere-Falcon 50 and 900 Series Airplanes, and Model Falcon 2000 and 900EX Series Airplanes

This amendment adopts a new airworthiness directive (AD), applicable to certain Dassault Model Mystere-Falcon 50 and 900 series airplanes, and Model Falcon 2000 and 900EX series airplanes. This proposal requires temporary changes to the Airplane Flight Manual to prohibit the use of certain functions depending on whether or not the operator chooses to deactivate the global positioning system (GPS). For airplanes on which the GPS is deactivated, this proposal requires installing a deactivation locking collar on certain circuit breakers. For certain airplanes, this proposal also requires modifying the wiring of the global positioning/inertial reference system. This action is necessary to prevent the erroneous cockpit display of ground speed, wind velocity and direction, flight path angle, and true track angle when using certain autopilot and/or flight management system functions. Erroneous cockpit displays could cause the pilot to lose situational awareness, and possibly lose control of the airplane. This action is intended to address the identified unsafe condition.