core lock

English

Noun

core lock (uncountable)

1. (aviation, mechanical engineering) Seizure of a turbine engine due to misalignment and loss of clearance between stationary and rotating components, caused by different components cooling and contracting at different rates following engine shutdown or flameout.
   • 2007 January 9, National Transportation Safety Board, “2.2.3 Double Engine Failure”, in Aircraft Accident Report: Crash of Pinnacle Airlines Flight 3701, Bombardier CL-600-2B19, N8396A, Jefferson City, Missouri, October 14, 2004‎^[1], archived from the original on 15 March 2022, page 49:

     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.

Verb

core lock (third-person singular simple present core locks, present participle core locking, simple past and past participle core locked)

1. (aviation, mechanical engineering, of a turbine engine) To experience core lock.
   • 2007 January 9, National Transportation Safety Board, “1.18.2 Core Lock”, in Aircraft Accident Report: Crash of Pinnacle Airlines Flight 3701, Bombardier CL-600-2B19, N8396A, Jefferson City, Missouri, October 14, 2004‎^[2], archived from the original on 15 March 2022, page 37:

     As testimony during the Safety Board’s June 2005 public hearing on the Pinnacle Airlines accident indicated, neither Bombardier nor GE considered core lock to be a safety-of-flight issue. The manufacturers claimed that engines that passed the screening procedure, with or without grind-in rework, would not core lock as long as the 240-knot airspeed was maintained.