.
see also: minimum equipment list (MEL)

Fr: liste principale d’équipement minimal
MATWP Abbreviation for: missed approach turning waypoint Fr: MATWP
MAWP Abbreviation for: missed approach waypoint Fr: MAWP
maximum authorized altitude U.S.: A published altitude representing the maximum usable altitude or flight level (FL) for an airspace structure or route segment. It is the highest altitude on a Federal airway, jet route, area navigation low or high route, or other direct route for which a minimum en route altitude (MEA) is designated in FAR 95 at which adequate reception of NAVAID signals is assured.
. abbreviation: MAA
“Mayday” An expression meaning “I am in distress.” It is the international radiotelephony distress signal. Preferably spoken three times, it indicates imminent and grave danger and means that immediate assistance is requested. Fr: . Mayday .
MCA U.S.: Abbreviation for: minimum crossing altitude
MDA Abbreviation for: minimum descent altitude Fr: MDA
MEA Abbreviation for: minimum en route altitude Fr: MEA
mean wind The wind direction and speed as determined from a sample reading taken every second over a  two-minute period. Fr: vent moyen
MEDEVAC An expression used to request ATS priority handling for a medical evacuation flight based on a medical emergency in the transport of patients, organ donors, organs or other urgently needed life-saving medical material. This expression is to be used on flight plans (FP) and in radiotelephone communications if a pilot determines that a priority is required. Fr: MEDEVAC
MEL Abbreviation for: minimum equipment list Fr: MEL
message Any thought or idea expressed briefly in a plain, coded, or secret language and prepared in a form suitable for transmission by any means of communication.
. abbreviation: MSG
Fr: message
meteorological bulletin
ICAO: A text comprising meteorological information preceded by an appropriate heading.
Fr: bulletin météorologique
meteorological information Information supplied to operators and flight crew members that includes upper winds and upper air temperatures, significant en route weather phenomena, meteorological reports, aerodrome forecasts, forecasts for takeoff, landing forecasts, SIGMET and air reports that are available at the meteorological office and that are relevant to the planned flight operations.
. also called: weather information
Fr: renseignements météorologiques
meteorological office
An office designated to provide a meteorological service.
Fr: bureau météorologique
meteorological report
A statement of observed meteorological conditions relating to a specified time and location.
Fr: bulletin météorologique
metering A method of time-regulating arrival traffic flow into a terminal area so as not to exceed a predetermined terminal acceptance rate. Fr: minutage