Definition
An FAA-issued document, developed for a specific aircraft make and model, that identifies the items of equipment that may be inoperative while the aircraft is still considered airworthy for flight under specified conditions. The MMEL is the regulatory baseline from which an operator builds its own approved Minimum Equipment List (MEL); the operator's MEL may be equally or more restrictive than the MMEL but never less restrictive.
Plain English
The MMEL is the FAA's master list, for a particular aircraft type, of which broken items the airplane can still legally fly with and under what limits. Operators use it as the starting point to write their own approved list for their specific airplane.
Context Anchor
You encounter MMELs when deciding whether an aircraft with inoperative equipment can be flown, especially before dispatch or during preflight planning.
Derivation
Master here means the original, authoritative version that other versions are built from — like a master copy of a document. The FAA issues the master; operators tailor a copy of it to their own fleet.
Why Pilots Care
MMELs determine whether an aircraft meets regulatory standards for dispatch when equipment is not working, directly affecting flight legality and safety.
Intuition Check
Do not read “minimum equipment list” as “the least equipment an airplane needs to be safe.” Here it means a controlled list of certain items that may be inoperative only if the stated conditions are met.
Example Sentence 1
The operator's MEL was developed from the FAA's MMEL for that aircraft model and cannot be less restrictive than it.
Example Sentence 2
Operators create their own minimum equipment lists by adapting the approved MMELs for their specific fleet.