Glossary

This glossary contains information on terms, phrases and abbreviations used by the Aviation industry. While this list does not include all aviation terminology, it is the purpose of this glossary to aid the general viewer in better understanding aviation terms as it pertains to content on this website. A full list of aviation terminology can be found here.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

M

MAC

See mean aerodynamic chord

Mach meter

The instrument that displays the ratio of the speed of sound to the true airspeed an aircraft is flying.

Mach number

The ratio of the true airspeed of the aircraft to the speed of sound in the same atmospheric conditions, named in honor of Ernst Mach, late 19th century physicist.

Magnetic bearing (MB)

The direction to or from a radio transmitting station measured relative to magnetic north.

Magnetic compass

A device for determining direction measured from magnetic north.

Magnetic dip

A vertical attraction between a compass needle and the magnetic poles. The closer the aircraft is to a pole, the more severe the effect.

Magnetic heading (MH)

The direction an aircraft is pointed with respect to magnetic north.

Magneto

A self-contained, engine-driven unit that supplies electrical current to the spark plugs; completely independent of the airplane’s electrical system. Normally there are two magnetos per engine.

Magnus effect

Lifting force produced when a rotating cylinder produces a pressure differential. This is the same effect that makes a baseball curve or a golf ball slice.

Maneuverability

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

Maneuvering speed (VA)

The maximum speed at which full, abrupt control movement can be used without overstressing the airframe.

Manifold absolute pressure

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

Mass

The amount of matter in a body.

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.