Core lock
Encyclopedia
Core lock is a jet engine
failure that can happen on aircraft in flight, after an engine stops working for a period. When a jet engine has a flameout
, the cooling air no longer circulates normally. If an aircraft is moving slowly, the sizes of some engine parts may change quicker than others, such that they no longer fit together as designed. If this happens, the engine may seize. On an internal combustion engine
that is not subject to extreme flight conditions, this may not be a problem. However, aircraft jet engines are built to exacting standards; core lock makes it difficult for pilots to windmill restart or perform an APU
-assisted engine restart.
accident.
"the pilots' failure to achieve and maintain the target airspeed in the double engine failure checklist, which caused the engine cores to stop rotating and resulted in the core lock engine condition. Contributing to this accident was 1) the engine core lock condition, which prevented at least one engine from being restarted, and 2) the airplane flight manuals that did not communicate to pilots the importance of maintaining a minimum airspeed to keep the engine cores rotating..."
Jet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
failure that can happen on aircraft in flight, after an engine stops working for a period. When a jet engine has a flameout
Flameout
A flameout refers to the failure of a jet engine caused by the extinction of the flame in the combustion chamber. It can be caused by a number of factors, including fuel exhaustion; compressor stall; insufficient oxygen supply; foreign object damage ; severe inclement weather; and mechanical...
, the cooling air no longer circulates normally. If an aircraft is moving slowly, the sizes of some engine parts may change quicker than others, such that they no longer fit together as designed. If this happens, the engine may seize. On an internal combustion engine
Internal combustion engine
The internal combustion engine is an engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber. In an internal combustion engine, the expansion of the high-temperature and high -pressure gases produced by combustion apply direct force to some component of the engine...
that is not subject to extreme flight conditions, this may not be a problem. However, aircraft jet engines are built to exacting standards; core lock makes it difficult for pilots to windmill restart or perform an APU
Auxiliary power unit
An auxiliary power unit is a device on a vehicle that provides energy for functions other than propulsion. They are commonly found on large aircraft, as well as some large land vehicles.-Function:...
-assisted engine restart.
Pinnacle Airlines Flight 3701
Core lock was cited as one of the contributing causes to the Pinnacle Airlines Flight 3701Pinnacle Airlines Flight 3701
Pinnacle Airlines Flight 3701 crashed on October 14, 2004, near Jefferson City, Missouri, United States. It was an overnight ferry flight from Little Rock, Arkansas, U.S. to Minneapolis-St. Paul International Airport, U.S...
accident.
"the pilots' failure to achieve and maintain the target airspeed in the double engine failure checklist, which caused the engine cores to stop rotating and resulted in the core lock engine condition. Contributing to this accident was 1) the engine core lock condition, which prevented at least one engine from being restarted, and 2) the airplane flight manuals that did not communicate to pilots the importance of maintaining a minimum airspeed to keep the engine cores rotating..."