core lock

The lack of core rotation on the accident airplane engines was similar to the instances of core lock experienced by CF34 engines during Bombardier’s acceptance testing, except that the accident airplane engines were exposed to more severe thermal distress than the engines on the production airplanes. Specifically, the accident airplane’s engines flamed out from high power and high altitude, whereas the engines installed on the production airplanes were shut down only after their internal temperatures were stabilized.