MEL

MEL (Minimum Equipment List) is a document that lists aircraft systems and equipment that may be inoperative for dispatch, provided specific conditions and procedures are followed. The MEL is derived from the Master MEL (MMEL) issued by the aircraft manufacturer and approved by the regulatory authority.

Each MEL item specifies: the number that may be inoperative, any required maintenance actions, operational limitations, and the maximum time permitted for repair (typically categories A: as specified, B: 3 days, C: 10 days, D: 120 days).