Definition
A permanent maintenance record kept for an aircraft engine, documenting its total operating time, inspections performed, repairs, overhauls, component replacements, airworthiness directive compliance, and any other maintenance actions required by regulation. The engine logbook travels with the engine, not the airframe, so if the engine is removed and installed on another aircraft, its logbook goes with it.
Plain English
A required record book that tracks everything that has happened to a specific engine — how many hours it has run, what work has been done on it, and when it was last inspected. It stays with that engine for its entire life.
Context Anchor
You will see an engine logbook when reviewing aircraft maintenance records, during inspections, or before buying, renting, or returning an aircraft to service after engine work.
Derivation
From 'log,' originally a wooden float (a 'log') trailed behind a ship to measure speed, with results recorded in a 'log book.' The term carried over to aviation to mean any official running record of operation and maintenance.
Why Pilots Care
Provides the documented evidence of airworthiness, maintenance history, and regulatory compliance needed for safe operation and legal transfer of the aircraft.
Analogy
It is like a medical record for the engine. You do not judge health only by how someone looks today; you also want to know the history of checkups, repairs, and major problems.
Intuition Check
Do not confuse an engine logbook with a pilot’s flight logbook. A pilot logbook records a person’s flying time; an engine logbook records the maintenance history of one specific engine.
Example Sentence 1
Before signing off the annual inspection, the mechanic recorded the work and the engine's total time in the engine logbook.
Example Sentence 2
The buyer asked to see the engine logbook before agreeing to purchase the aircraft.