Transport Canada CF-2023-01

Mandates a revision to the airplane flight manual to incorporate additional instructions in the “Ground Spoilers Unsafe and Weight-on-Wheels Input Fault” abnormal procedures to prevent ground spoilers from deploying in air. Prompted by an investigation into an in-service aircraft event during which ground spoilers deployed in air while the airplane was on approach to landing. After takeoff, the weight on wheels “INPUT” caution message appeared on the EICAS and persisted throughout the flight even after the flight crew executed the “WOW INPUT” quick reference handbook procedure. During this time,
the ground spoilers “NOT ARMED” message also posted and, consequently, the flight crew manually armed the ground spoilers as required by the procedure for that message. The investigation revealed that a fault had occurred in the proximity sensor electronic unit, which erroneously indicated “ON GROUND” while the aircraft was in the air.