What Is MEL? Definition & Meaning in Aviation
An MEL (minimum equipment list) is the list of equipment that is allowed to be broken on an aircraft while it still flies, and under which conditions.
In plain language
Regulators approve each airline’s MEL. It lets an aircraft fly with a minor fault, such as an inoperative reading light, but not with a safety-critical failure.
Example
A flight may depart with an inoperative cabin item under the MEL, while a fault in a flight-critical system keeps the aircraft on the ground.
Why it matters
The MEL explains why a flight sometimes departs with a minor fault, and why a more serious fault delays or cancels a flight. It is a safety system, not a loophole: every item has conditions.