MEL stands for Minimum Equipment List. It is a regulatory document that lists the minimum equipment required for the aircraft to be dispatched legally and safely. The MEL specifies which systems and instruments can be inoperative for a flight and the conditions under which it can be dispatched with those items. The A320 and A321 share an MEL because they are part of the same aircraft family, though specific items can be tailored by an airline.
What the MEL includes
- Operational procedures: What pilots must follow in the cockpit if a non-critical system is not working.
- Maintenance procedures: What maintenance personnel must do to fix the inoperative item.
- Repair intervals: The maximum time an item can be deferred before it must be repaired.
How it is used
- For dispatch: The MEL ensures that even if a non-critical component fails, the aircraft still meets the minimum safety requirements for flight.
- For the crew: Pilots use the MEL to know if a flight can depart and what restrictions or procedures to follow if a system is inoperative.
- For maintenance: The MEL dictates the timeframe within which a faulty item must be fixed.
Key points
- An aircraft can fly with a system listed on the MEL as inoperative, as long as the crew follows the specified conditions and procedures.
- An aircraft cannot fly if an item that is not on the MEL is inoperative.
- Each airline develops its own specific MEL, based on the Master Minimum Equipment List (MMEL), but it cannot be less restrictive than the master list and must comply with all airworthiness directives.
- The A320 and A321 often have a combined MEL because they are part of the same family of aircraft.