M Mike

M/A (Monitor-Alert) - A function of the ETMS that provides traffic management personnel with a tool for predicting potential capacity problems in individual operational sectors. The M/A is an indication that traffic management personnel need to analyze a particular sector for actual activity and to determine the required action(s), if any, needed to control the demand.

magnetic field - A space where magnetic lines of force exist.

magnetic heading - The direction in which the longitudinal axis of the airplane is pointing according to a magnetic compass.

magnetic variation - Difference between true north and magnetic north, varying with position; magnetic variation drifts with time.

magneto - A small generator of alternating current with permanent magnets, used in the ignition system of most modern aircraft engines because it produces a hotter spark at high engine speeds than a typical automobile battery system, and it does not depend on an external source of energy.

main gear - The landing gear underneath the fuselage of an aircraft.

marker beacons - A radio navigation aid used in the approach zone of an instrumented airport. As the airplane crosses over each of three marker beacon transmitters, the pilot receives an accurate indication of the airplane's distance from the runway through the medium of a flashing light an aural signal.

mean sea level - The average height of the surface of the sea for all stages of tide.

megahertz - One million cycles per second, used especially as a radio frequency unit.

meridian - See longitude.

METAR (METeorological Aerodrome Report) - It is the primary observation code used in the United States to satisfy requirements for reporting surface meteorological data. Minimum reporting requirements includes wind, visibility, runway visual range, present weather, sky condition, temperature, dew point, and altimeter setting.

meter - A method of time-regulating arrival traffic flow into a terminal area so as not to exceed a predetermined terminal acceptance rate.

MHz - see megahertz

microsecond - One millionth of a second.

Mike - Designator for the letter "M" in the International Phonetic Alphabet.

military aviation - The operation of aircraft that belong to the Armed Forces.

MM (Middle Marker) - Marker beacon located where the center of the glideslope is at the point of decision (200 feet above the runway). The signal is received both aurally and visually by cockpit equipment (compatible airborne equipment).

model - A copy of an object that is often times smaller than the original.
Wind tunnel engineers create a model of an aircraft to put in a tunnel. The model is a precise replica of the outside of an aircraft.

moisture - Refers to the water vapor content in the atmosphere, or the total water, liquid, solid or vapor, in a given volume of air.

molecule - The absolute tiniest part of something, that can still be called by that name. For example, two hydrogen atoms and one oxygen atom make up one molecule of water.

monoplane - An airplane with one set of wings. Most aircraft built today have only one set of wings and are classified as monoplanes.

mountain wind - Cool, heavy air that sinks and flows down a mountain slope.