Factual Report: CRJ loses cowling in flight

 - November 4, 2008, 5:58 AM

Bombardier CRJ CL-600-2B19, Lake Michigan, Mich., April 7, 2007–At 16,000 feet over Lake Michigan, the Mesa Airlines CRJ thrust reverser translating cowling separated from the left engine and struck the horizontal and vertical stabilizers, substantially damaging the airplane. Before takeoff from Capital City Airport in Lansing, the crew had noted a left thrust reverser unlock master caution and engine indication and crew alert system (EICAS) indications. The captain cycled the reverser a few times and eventually the thrust reversers appeared to be operating normally, so they proceeded to take off for Chicago O’Hare (ORD). On climb-out, the captain noticed a small vibration, then at cruise he heard a “loud bang” and said the “aircraft pitched and yawed/ rolled to [the] left.” The autopilot disengaged and the left thrust lever moved to idle. The first officer stowed the reverser. The captain elected to continue to ORD after the thrust reverser unlock messages had cleared and the vibrations had stopped. The airplane subsequently landed uneventfully at ORD, where the cowling was discovered to be missing and the damage noted. Maintenance records revealed a history of anomalies related to the left-engine thrust reverser.