Definition
The running condition of the airplane's engine during a specific phase of flight or ground operation, evaluated by checking instrument indications (RPM, manifold pressure, oil pressure, oil temperature, fuel flow, EGT, etc.), engine response to throttle and mixture inputs, and the absence of roughness, vibration, or unusual sounds. During the before-takeoff check, engine operation is confirmed to be smooth, within published limits, and producing the expected power before the airplane is committed to takeoff.
Plain English
How the engine is running — whether it sounds right, responds correctly to control inputs, and shows normal readings on the gauges.
Context Anchor
Seen during the before-takeoff check, after engine start and before taking the runway.
Why Pilots Care
Problems found during this check can be corrected safely on the ground; the same issue after liftoff can lead to an in-flight emergency or forced landing.
Intuition Check
Engine operation does not mean simply that the engine is on. In this checklist context, it means the engine is running properly, making expected power, and responding correctly.
Example Sentence 1
During the run-up, the pilot checked engine operation by cycling the magnetos, exercising the propeller, and confirming all engine instruments were in the green.
Example Sentence 2
Any roughness noted during the engine operation check prompted the pilot to lean the mixture briefly to clear the spark plugs before continuing the checklist.