A minimum equipment list is a list used in aviation specifying what equipment, at a minimum, must be installed and in working order before an aircraft takes flight. Equipment covered on the list is extensive and varies widely from such things as windows and doors to fuel and flight systems to emergency equipment and more. Such lists are specific to individual aircraft and are developed from the Master Minimum Equipment List maintained by the governing body for a particular locale. Rotary craft and lighter than air craft as well as more standard aircraft such as airplanes all may have minimum equipment lists.
To develop a minimum equipment list for a specific aircraft, the owner or operator should acquire a copy of the Master Minimum Equipment List. This list can generally be requested from the applicable governing body for the locale. Going through this master list as well as flight, maintenance, and other manuals for the specific aircraft will help in the creation of an appropriate document.
Upon development of the minimum equipment list for his or her aircraft, the owner or operator submits the document to the applicable governing body for approval. This governing body is usually an aviation authority of the government with jurisdiction over his or her location. The Federal Aviation Administration in the United States, the Civil Aviation Authority in the United Kingdom, and Transport Canada, for example, have legal authority over approvals in their jurisdictions. Once this list is approved for a specific aircraft, it becomes the governing document for the aircraft superseding the more general master list. A minimum equipment list approved for a particular aircraft is specific only to that aircraft and is not transferable to another aircraft.
The minimum equipment list covers a wide array of aircraft equipment and specifies the necessary procedures to mitigate deficiencies when this equipment goes missing or becomes inoperable. Electrical and hydraulic power systems, fuel systems, and oxygen systems are covered, as are flight indicators, navigation equipment, landing gear, and other devices necessary for safe aircraft operation. Equipment such as fire protection, medical and survival equipment, data recorders, and other items are also covered although they are not necessary for aircraft operation under normal conditions.
If an item on the aircraft is found to be missing or inoperable, the operator checks the minimum equipment list for the necessary procedure to correct the deficiency. The list documents who is authorized to correct each of the deficiencies covered. Some deficiencies may be corrected by the operator. Only an authorized mechanic may correct other deficiencies, generally those of a more technical nature. All deficiencies must be addressed before an aircraft is deemed ready for flight.