Airworthiness Directives; Bombardier, Inc. Airplanes

We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL-600-1A11 (CL-600) airplanes. This AD requires revising the airplane flight manual to prohibit thrust reverser operation, and repetitive detailed inspections of both engine thrust reversers for cracks and modification if necessary. The modification of the thrust reversers is also an optional terminating action for the repetitive inspections. This AD was prompted by reports of partial deployment of an engine thrust reverser in-flight caused by a failure of the translating sleeve at the thrust reverser attachment points. We are issuing this AD to detect and correct cracks of the translating sleeve at the thrust reverser actuator attachment points, which could result in deployment or dislodgement of an engine thrust reverser in- flight and subsequent reduced control of the airplane.