Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Dassault Model Mystere-Falcon 50 and 900 series airplanes, and Model Falcon 2000 and 900EX series airplanes. This proposal would require 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 would require installing a deactivation locking collar on certain circuit breakers. For certain airplanes, this proposal would also require modifying the wiring of the global positioning/inertial reference system. This action is necessary to prevent the erroneous display of speed to the flightcrew, when using certain functions, which could cause the flightcrew to lose situational awareness, and possibly lose control of the airplane. This action is intended to address the identified unsafe condition.