Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500- 1A11 airplanes. This AD was prompted by reports that, during instrument landing system (ILS) approaches, the flight control system reverted from primary flight control computer (PFCC) normal mode operating in autopilot to remote electronics unit (REU) direct mode, and then, after a period of time, to PFCC direct mode. This AD requires installation of a PFCC software update; and a records review or detailed inspection to identify pre-existing repairs or damage within certain limits to certain structures, and obtaining and following additional instructions, if necessary, as specified in a Transport Canada AD, which is incorporated by reference. The FAA is issuing this AD to address the unsafe condition on these products.