Maneuverability. Ability of an aircraft to change directions along a flight path and withstand the stresses imposed upon it. 

Maneuvering speed (V$_{A}$). The design maneuvering speed. Operating at or below design maneuvering speed does not provide structural protection against multiple full control inputs in one axis or full control inputs in more than one axis at the same time. 

Manifold absolute pressure. The absolute pressure of the fuel/air mixture within the intake manifold, usually indicated in inches of mercury. 

MAP.  See missed approach point. 

Margin identification.  The top and bottom areas on an instrument approach chart that depict information about the procedure, including airport location and procedure identification. 

Marker beacon.  A low-powered transmitter that directs its signal upward in a small, fan-shaped pattern. Used along the flight path when approaching an airport for landing, marker beacons indicate both aurally and visually when the aircraft is directly over the facility. 

Mass. The amount of matter in a body. 

Maximum altitude.  An altitude depicted on an instrument approach chart with overscored altitude value at which or below aircraft are required to maintain altitude. 

Maximum authorized altitude (MAA).  A published altitude representing the maximum usable altitude or flight level for an airspace structure or route segment. 

Maximum landing weight. The greatest weight that an airplane normally is allowed to have at landing. 

Maximum ramp weight. The total weight of a loaded aircraft, including all fuel. It is greater than the takeoff weight due to the fuel that will be burned during the taxi and runup operations. Ramp weight may also be referred to as taxi weight. 

Maximum takeoff weight. The maximum allowable weight for takeoff. 

Maximum weight. The maximum authorized weight of the aircraft and all of its equipment as specified in the Type Certificate Data Sheets (TCDS) for the aircraft. 

Maximum zero fuel weight (GAMA). The maximum weight, exclusive of usable fuel. 

MB.  See magnetic bearing. 

MCA.  See minimum crossing altitude. 

MDA.  See minimum descent altitude. 

MEA.  See minimum en route altitude. 

Mean aerodynamic chord (MAC). The average distance from the leading edge to the trailing edge of the wing. 

Mean sea level. The average height of the surface of the sea at a particular location for all stages of the tide over a 19-year period. 

MEL. See minimum equipment list. 

Meridians. Lines of longitude. 

Mesophere. A layer of the atmosphere directly above the stratosphere. 

METAR. See Aviation Routine Weather Report. 

MFD. See multi-function display. 

MH.  See magnetic heading. 

MHz. Megahertz. 

Microburts. A strong downdraft which normally occurs over horizontal distances of 1 NM or less and vertical distances of less than 1,000 feet. In spite of its small horizontal scale, an intense microburst could induce windspeeds greater than 100 knots and downdrafts as strong as 6,000 feet per minute. 

Microwave landing system (MLS).  A precision instrument approach system operating in the microwave spectrum which normally consists of an azimuth station, elevation station, and precision distance measuring equipment. 

Mileage breakdown.  A fix indicating a course change that appears on the chart as an “x” at a break between two segments of a federal airway. 

Military operations area (MOA).  Airspace established for the purpose of separating certain military training activities from IFR traffic. 

