Minimum equipment list
Encyclopedia
In aviation
, a Master Minimum Equipment List, or MMEL, is a categorized list of systems, instruments and equipment on an aircraft
which are not required to be operative for flight. Specific procedures or conditions may be associated with operation with the relevant item inoperative. Any equipment or system which is not included in the MMEL must be operative for the aircraft to be allowed to fly. Each aircraft model generally has a distinct MMEL.
and European Joint Aviation Requirements
forbid aircraft with inoperative equipment from flight, except in certain conditions. One of these conditions is that the aircraft have a minimum equipment list that indicates which items may be inoperative and the conditions under which each item may be inoperative for flight.
Even seemingly insignificant items such as light bulbs in the cabin may be on the MEL, as light bulbs are still part of the electrical system and thus part of the airplane's equipment (and potentially important for the safety of flight). Of course, a simple light bulb in the cabin may not be essential to safety, and so it may be noted as not necessary for flight if it appears on the MEL.
of the countries where the aircraft will operate.
In the United States
, a minimum equipment list is required by the Federal Aviation Administration
:
The same kind of regulation is enforced by aviation authorities in other nations, such as the European Aviation Safety Agency
.
Aviation
Aviation is the design, development, production, operation, and use of aircraft, especially heavier-than-air aircraft. Aviation is derived from avis, the Latin word for bird.-History:...
, a Master Minimum Equipment List, or MMEL, is a categorized list of systems, instruments and equipment on an aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
which are not required to be operative for flight. Specific procedures or conditions may be associated with operation with the relevant item inoperative. Any equipment or system which is not included in the MMEL must be operative for the aircraft to be allowed to fly. Each aircraft model generally has a distinct MMEL.
Overview
The US Federal Aviation RegulationsFederal Aviation Regulations
The Federal Aviation Regulations, or FARs, are rules prescribed by the Federal Aviation Administration governing all aviation activities in the United States. The FARs are part of Title 14 of the Code of Federal Regulations...
and European Joint Aviation Requirements
Joint Aviation Requirements
The Civil Aviation Authorities of certain European countries have agreed common comprehensive and detailed aviation requirements — referred to as the Joint Aviation Requirements — with a view to minimising Type Certification problems on joint ventures, and also to facilitate the export...
forbid aircraft with inoperative equipment from flight, except in certain conditions. One of these conditions is that the aircraft have a minimum equipment list that indicates which items may be inoperative and the conditions under which each item may be inoperative for flight.
Even seemingly insignificant items such as light bulbs in the cabin may be on the MEL, as light bulbs are still part of the electrical system and thus part of the airplane's equipment (and potentially important for the safety of flight). Of course, a simple light bulb in the cabin may not be essential to safety, and so it may be noted as not necessary for flight if it appears on the MEL.
Implementation
Minimum equipment lists are issued to specific aircraft and specific operators. In order for an operator to use a minimum equipment list, the operator must receive a letter of authorization from the national aviation authoritiesNational aviation authority
The National Aviation Authority is the government statutory authority in each country that oversees the approval and regulation of civil aviation.-Role:...
of the countries where the aircraft will operate.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, a minimum equipment list is required by the Federal Aviation Administration
Federal Aviation Administration
The Federal Aviation Administration is the national aviation authority of the United States. An agency of the United States Department of Transportation, it has authority to regulate and oversee all aspects of civil aviation in the U.S...
:
- When operating any turbine-powered aircraft such as jetsJet aircraftA jet aircraft is an aircraft propelled by jet engines. Jet aircraft generally fly much faster than propeller-powered aircraft and at higher altitudes – as high as . At these altitudes, jet engines achieve maximum efficiency over long distances. The engines in propeller-powered aircraft...
or turboprops.TurbopropA turboprop engine is a type of turbine engine which drives an aircraft propeller using a reduction gear.The gas turbine is designed specifically for this application, with almost all of its output being used to drive the propeller... - When operating under part 135 (Commuter and on-demand operations)
- When operating under part 125 (Non-airline large aircraft operations)
The same kind of regulation is enforced by aviation authorities in other nations, such as the European Aviation Safety Agency
European Aviation Safety Agency
The European Aviation Safety Agency is an agency of the European Union with offices in Cologne, Germany, which has been given regulatory and executive tasks in the field of civilian aviation safety. It was created on 15 July 2002, and it reached full functionality in 2008, taking over functions...
.