Definition
A document developed by the FAA for a specific aircraft make and model that lists items of equipment which may be inoperative while still allowing the aircraft to be dispatched for flight, along with any conditions or limitations that apply. The MMEL is the source document an operator uses to build their own approved Minimum Equipment List (MEL) for a particular aircraft.
Plain English
An FAA-issued list, made for a specific aircraft type, showing which pieces of equipment are allowed to be broken or missing and the aircraft can still legally fly. Operators use this master list as the starting point to create their own list for their specific aircraft.
Context Anchor
Seen when deciding whether a helicopter with a failed item can be flown using an approved Minimum Equipment List.
Derivation
‘Master’ here means the original, top-level reference document from which other versions are made. Just as a master copy is the source other copies come from, the MMEL is the FAA source document that each operator’s MEL is built from.
Why Pilots Care
Determines whether an aircraft with certain inoperative equipment can be legally and safely dispatched rather than grounded.
Intuition Check
Do not read “master” as the list you normally use directly in the cockpit, and do not read “minimum” as permission to fly with anything broken. The Master Minimum Equipment List is the approved baseline; the aircraft’s approved Minimum Equipment List gives the actual go/no-go guidance for that aircraft.
Example Sentence 1
The operator developed its MEL using the MMEL issued by the FAA for that helicopter model.
Example Sentence 2
Operators create their own MEL from the Master Minimum Equipment List to match their specific helicopter configuration and mission.