Minimum Equipment list (MEL)

November 29, 2017December 20, 2015 by aeinfo

The Minimum Equipment List (MEL) is a document and method prepared by aircraft operators. MEL is use to obtain relief from Aviation Regulations requiring that all equipment installed on the aircraft be operative at the time of flight.

MEL is aircraft specific. which means different from aircraftto aircraft.The minimum equipment list (MEL ) will specify the circumstances under which a particular aircraft can fly with equipment non-operative as deferred defects. It will specify the condition of the rest of the system (if part of the system is affected) and the condition of the rest of any associated systems. It will detail as appropriate such things as flight duration times, performance limitations etc. See also tech Logs.
Sometimes called Dispatch Deviation List (DDL).There will also be a list of certification limits (CDL) putting limitations on the use of the aircraft with that deferred defect.

The MEL is developed from the Master Minimum Equipment List (MMEL), MMEL is produced by the aircraft manufacturer and approved during certification of the airplane.

Master Minimum Equipment list

Aircraft minimum Equipment list ( MEL )

MMELs are produced by the constructor for all recent aircraft types, exceeding 2730kg MTOM and are applicable to particular types of aircraft, but they do not take into consideration the varying operating conditions of individual operators.

MELs are produced by the individual operators using MMELs as the basis, and then approved by the CAA. They must be no less restrictive than MMELs, and are usually more restrictive.
When approved the MELs become part of the Flight/Operations Manual.
Amendments are permitted only if approved by the CAA.
When an aircraft is allowed to fly with a defect – this is listed along with details of the flight, eg duration; whether over the sea or not; etc. When an ETOPS aircraft is flown on an ETOPS flight the Minimum Equipment List will be restricted.