Airworthiness Directives; Bombardier, Inc. Airplanes

We propose to adopt a new airworthiness directive (AD) for certain Bombardier, Inc. Model BD-700-1A10 and BD-700-1A11 airplanes. This proposed AD was prompted by a determination that the existing instruction in a certain task in the aircraft maintenance manual (AMM) will not accomplish the intent of a certification maintenance requirement (CMR). This CMR task tests the pitch feel (PF) and rudder travel limiter actuator (RTLA) back-up modules in the flight control unit (FCU) to detect dormant failures. This proposed AD would require doing an operational test of the FCU back-up modules, and repair if necessary. We are proposing this AD to detect and correct a dormant failure of both FCU back-up modules. This condition, in combination with other failures in the FCU, may result in the inability to maintain the minimum control requirements for the PF and RTLA, which could create hazardous flight control inputs during flight.