Aeronautical Terms beginning with M
Minimum IFR Altitude (MIA)
Minimum altitudes for IFR operations are prescribed in Part 91. These MIAs are published on NACO charts and prescribed in Part 95 for airways and routes, and in Part 97 for standard instrument approach procedures.
Minimum Navigation Performance Specifications (MNPS)
A set of standards which require aircraft to have a minimum navigation performance capability in order to operate in MNPS designated airspace. In addition, aircraft must be certified by their State of Registry for MNPS operation. Under certain conditions, non-MNPS aircraft can operate in MNPS airspace, however, standard oceanic separation minima is provided between the non-MNPS aircraft and other traffic.
Minimum Obstruction Clearance Altitude (MOCA)
The MOCA is the lowest published altitude in effect between radio fixes on VOR airways, off-airway routes, or route segments that meets obstacle clearance requirements for the entire route segment. This altitude also assures acceptable navigational signal coverage only within 22 NM of a VOR.
Minimum Reception Altitude (MRA)
An MRA is determined by FAA flight inspection traversing an entire route of flight to establish the minimum altitude the navigation signal can be received for the route and for off-course NAVAID facilities that determine a fix. When the MRA at the fix is higher than the MEA, an MRA is established for the fix, and is the lowest altitude at which an intersection can be determined.
Minimum Safe Altitudes (MSA)
MSAs are published for emergency use on IAP charts. For conventional navigation systems, the MSA is normally based on the primary omnidirectional facility on which the IAP is predicated. For RNAV approaches, the MSA is based on the runway waypoint (RWY WP) for straight in approaches, or the airport waypoint (APT WP) for circling approaches. For GPS approaches, the MSA center will be the Missed Approach Waypoint (MAWP).
Minimum Vectoring Altitude (MVA)
Minimum vectoring altitude charts are developed for areas where there are numerous minimum vectoring altitudes due to variable terrain features or man-made obstacles. MVAs are established for use by ATC when radar ATC is exercised.
Missed Approach Holding Waypoint (MAHWP)
An approach waypoint sequenced during the holding portion of the missed approach procedure that is usually a fly-over waypoint, rather than a fly-by waypoint.
Magnetic Variation
The difference in degrees between the measured values of true north and magnetic north at that location.
Maximum Authorized Altitude (MAA)
An MAA is a published altitude representing the maximum usable altitude or flight level for an airspace structure or route segment. It is the highest altitude on a Federal airway, jet route, RNAV low or high route, or other direct route for which an MEA is designated at which adequate reception of navigation signals is assured.
Metering Fix
A fix along an established route over which aircraft will be metered prior to entering terminal airspace. Normally, this fix should be established at a distance from the airport which will facilitate a profile descent 10,000 feet above airport elevation (AAE) or above.
Mileage Break
A point on a route where the leg segment mileage ends, and a new leg segment mileage begins, often at a route turning point.
Military Airspace Management System (MAMS)
A Department of Defense system to collect and disseminate information on the current status of special use airspace. This information is provided to the Special Use Airspace Management System (SAMS). The electronic interface also provides SUA schedules and historical activation and utilization data.
Minimum Crossing Altitude (MCA)
An MCA is the lowest altitude at certain fixes at which the aircraft must cross when proceeding in the direction of a higher minimum en route IFR altitude. MCAs are established in all cases where obstacles intervene to prevent pilots from maintaining obstacle clearance during a normal climb to a higher MEA after passing a point beyond which the higher MEA applies.
Minimum Descent Altitude (MDA)
The lowest altitude, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering in execution of a standard instrument approach procedure where no electronic glide slope is provided.
Minimum En Route Altitude (MEA)
The MEA is the lowest published altitude between radio fixes that assures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes. The MEA prescribed for a Federal airway or segment, RNAV low or high route, or other direct route applies to the entire width of the airway, segment, or route between the radio fixes defining the airway, segment, or route.
Missed Approach Waypoint (MAWP)
An approach waypoint sequenced during the missed approach procedure that is usually a fly-over waypoint, rather than a fly-by waypoint.
Mach
Speed relative to the speed of sound. Mach 1 is the speed of sound.
Mach Buffet
Airflow separation behind a shock-wave pressure barrier caused by airflow over flight surfaces exceeding the speed of sound.
Mach Compensating Device
A device to alert the pilot of inadvertent excursions beyond its certified maximum operating speed.
Mach Critical
The MACH speed at which some portion of the airflow over the wing first equals MACH 1.0. This is also the speed at which a shock wave first appears on the airplane.
Mach Tuck
A condition that can occur when operating a swept-wing airplane in the transonic speed range. A shock wave could form in the root portion of the wing and cause the air behind it to separate. This shock-induced separation causes the center of pressure to move aft. This, combined with the increasing amount of nose down force at higher speeds to maintain level flight, causes the nose to “tuck.” If not corrected, the airplane could enter a steep, sometimes unrecoverable dive.
Magnetic Compass
A device for determining direction measured from magnetic north.
Main Gear
The wheels of an aircraft’s landing gear that supports the major part of the aircraft’s weight.
Maneuverability
Ability of an aircraft to change directions along a flightpath and withstand the stresses imposed upon it.
Maneuvering Speed (Va)
The maximum speed where full, abrupt control movement can be used without overstressing the airframe.
Manifold Pressure (MP)
The absolute pressure of the fuel/air mixture within the intake manifold, usually indicated in inches of mercury.
Maximum Allowable Takeoff Power
The maximum power an engine is allowed to develop for a limited period of time; usually about one minute.
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.
Minimum Controllable Airspeed
An airspeed at which any further increase in angle of attack, increase in load factor, or reduction in power, would result in an immediate stall.
Minimum Drag Speed (L/Dmax)
The point on the total drag curve where the lift-to-drag ratio is the greatest. At this speed, total drag is minimized.
Mixture
The ratio of fuel to air entering the engine’s cylinders.
Moment
The product of the weight of an item multiplied by its arm. Moments are expressed in pound-inches (lb-in). Total moment is the weight of the airplane multiplied by the distance between the datum and the CG.
Moment Arm
The distance from a datum to the applied force.
Moment Index (Or Index)
A moment divided by a constant such as 100, 1,000, or 10,000. The purpose of using a moment index is to simplify weight and balance computations of airplanes where heavy items and long arms result in large, unmanageable numbers.
Movable Slat
A movable auxiliary airfoil on the leading edge of a wing. It is closed in normal flight but extends at high angles of attack. This allows air to continue flowing over the top of the wing and delays airflow separation.
Mushing
A flight condition caused by slow speed where the control surfaces are marginally effective.
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.
Mach meter
The instrument that displays the ratio of the speed of sound to the true airspeed an aircraft is flying.
Magnetic bearing (MB)
The direction to or from a radio transmitting station measured relative to magnetic north.
Magnetic heading (MH)
The direction an aircraft is pointed with respect to magnetic north.
Mandatory altitude
An altitude depicted on an instrument approach chart with the altitude value both underscored and overscored. Aircraft are required to maintain altitude at the depicted value.
Mandatory block altitude
An altitude depicted on an instrument approach chart with two underscored and overscored altitude values between which aircraft are required to maintain altitude.
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.
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.
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.
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.
Military training route (MTR)
Airspace of defined vertical and lateral dimensions established for the conduct of military training at airspeeds in excess of 250 knots indicated airspeed (KIAS).
Minimum altitude
An altitude depicted on an instrument approach chart with the altitude value underscored. Aircraft are required to maintain altitude at or above the depicted value.
Minimum crossing altitude (MCA)
The lowest allowed altitude at certain fixes an aircraft must cross when proceeding in the direction of a higher minimum en route altitude (MEA).
Minimum descent altitude (MDA)
The lowest altitude (in feet MSL) to which descent is authorized on final approach, or during circle-to-land maneuvering in execution of a nonprecision approach.
Minimum en route altitude (MEA)
The lowest published altitude between radio fixes that ensures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes.
Minimum obstruction clearance altitude (MOCA)
The lowest published altitude in effect between radio fixes on VOR airways, off-airway routes, or route segments, which meets obstacle clearance requirements for the entire route segment and which ensures acceptable navigational signal coverage only within 25 statute (22 nautical) miles of a VOR.
Minimum reception altitude (MRA)
The lowest altitude at which an airway intersection can be determined.
Minimum safe altitude (MSA)
The minimum altitude depicted on approach charts which provides at least 1,000 feet of obstacle clearance for emergency use within a specified distance from the listed navigation facility.
Minimum vectoring altitude (MVA)
An IFR altitude lower than the minimum en route altitude (MEA) that provides terrain and obstacle clearance.
Minimums section
The area on an IAP chart that displays the lowest altitude and visibility requirements for the approach.
Missed approach
A maneuver conducted by a pilot when an instrument approach cannot be completed to a landing.
Missed approach point (MAP)
A point prescribed in each instrument approach at which a missed approach procedure shall be executed if the required visual reference has not been established.
Mixed ice
A mixture of clear ice and rime ice.
Mode C
Altitude Reporting Transponder Mode.
Multi-function display (MFD)
Small screen (CRT or LCD) in an aircraft that can be used to display information to the pilot in numerous configurable ways. Often an MFD will be used in concert with a Primary Flight Display.
Matching-type test item
A test item in which the student is asked to match alternatives on one list to related alternatives on a second list. The lists may include words, terms, illustrations, phrases, or sentences.
Memory
The ability of people and other organisms to encode (initial perception and registration of information), store (retention of encoded information over time), and retrieve (processes involved in using stored information) information.
Mock-up
A three-dimensional working model used in which the actual object is either unavailable or too expensive to use. Mock-ups may emphasize some elements while eliminating nonessential elements.
Model
A copy of a real object which can be life-size, smaller, or larger than the original.
Motivation
A need or desire that causes a person to act. Motivation can be positive or negative, tangible or intangible, subtle or obvious.
Multimedia
A combination of more than one instructional medium. This format can include audio, text, graphics, animations, and video. Recently, multimedia implies a computer-based presentation.
Multiple-choice-type test item
A test item consisting of a question or statement followed by a list of alternative answers or responses.
Mach number
The ratio of true airspeed to the speed of sound.
Main rotor
The rotor that supplies the principal lift to a rotorcraft.
Maintenance
Inspection, overhaul, repair, preservation, and the replacement of parts, but excludes preventive maintenance.
Major alteration
An alteration not listed in the aircraft, aircraft engine, or propeller specifications—
(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or
(2) That is not done according to accepted practices or cannot be done by elementary operations.
Major repair
A repair:
(1) That, if improperly done, might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or
(2) That is not done according to accepted practices or cannot be done by elementary operations.
Manifold pressure
Absolute pressure as measured at the appropriate point in the induction system and usually expressed in inches of mercury.
Maximum engine overtorque
As it applies to turbopropeller and turboshaft engines incorporating free power turbines for all ratings except one engine inoperative (OEI) ratings of two minutes or less, the maximum torque of the free power turbine rotor assembly, the inadvertent occurrence of which, for periods of up to 20 seconds, will not require rejection of the engine from service, or any maintenance action other than to correct the cause. Maximum speed for stability characteristics, V FC/MFC means a speed that may not be less than a speed midway between maximum operating limit speed (VMO/MMO) and demonstrated flight diving speed (VDF/MDF), except that, for altitudes where the Mach number is the limiting factor, MFC need not exceed the Mach number at which effective speed warning occurs.
Medical certificate
Acceptable evidence of physical fitness on a form prescribed by the Administrator.
Military operations area
A military operations area (MOA) is airspace established outside Class A airspace to separate or segregate certain nonhazardous military activities from IFR Traffic and to identify for VFR traffic where theses activities are conducted.
Minimum descent altitude (MDA)
The lowest altitude specified in a [nonprecision] instrument approach procedure, expressed in feet above mean sea level, to which descent is authorized on final approach or during circle-to-land maneuvering until the pilot sees the required visual references for the heliport or runway of intended landing.
Minor alteration
An alteration other than a major alteration.
Minor repair
A repair other than a major repair.
Major Alteration
An alteration not listed in the aircraft, aircraft engine, or propeller specifications, (1) that might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or (2) that is not done according to accepted practices or cannot be done by elementary operations.
Maximum Landing Weight
(GAMA) Maximum weight approved for the landing touchdown.
Maximum Permissible Hoist Load
The maximum external load that is permitted for a helicopter to carry. This load is specified in the POH.
Maximum Ramp Weight
(GAMA) Maximum weight approved for ground maneuver. It includes weight of start, taxi, and runup fuel.
Maximum Takeoff Weight
(GAMA) Maximum weight approved for the start of the takeoff run.
Maximum Taxi Weight
Maximum weight approved for ground maneuvers. This is the same as maximum ramp weight.
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
The maximum authorized weight of an aircraft without fuel. This is the total weight for a particular flight less the fuel. It includes the aircraft and everything that will be carried on the flight except the weight of the fuel.
METO Horsepower (maximum except takeoff)
The maximum power allowed to be continuously produced by an engine. Takeoff power is usually limited to a given amount of time, such as 1 minute or 5 minutes.
Minimum Fuel
The amount of fuel necessary for one- half hour of operation at the rated maximum-continuous power setting of the engine, which, for weight and balance purposes, is 1/12 gallon per maximum-except-takeoff (METO) horse-power. It is the maximum amount of fuel that could be used in weight and balance computations when low fuel might adversely affect the most critical balance conditions. To determine the weight of the minimum fuel in pounds, divide the METO horsepower by two.
Minor Alteration
An alteration other than a major alteration. This includes alterations that are listed in the aircraft, aircraft engine, or propeller specifications.
Moment
A force that causes or tries to cause an object to rotate. It is indicated by the product of the weight of an item multiplied by its arm.
Moment
(GAMA) The product of the weight of an item multiplied by its arm. (Moment divided by a constant is used to simplify balance calculations by reducing the number of digits; see reduction factor.)
Moment Index
The moment (weight times arm) divided by a reduction factor such as 100 or 1,000 to make the number smaller and reduce the chance of mathematical errors in computing the center of gravity.
Moment Limits vs Weight Envelope
An enclosed area on a graph of three parameters. The diagonal line representing the moment/100 crosses the horizontal line representing the weight at the vertical line representing the CG location in inches aft of the datum. When the lines cross inside the envelope, the aircraft is loaded within its weight and CG limits.
Melting
The change of ice to liquid water.
Mammato cumulus
Obsolete. Now referred to as cumulonimbus mamma.
Mare’s tail
Irregularly curved wisps of cirriform clouds.
Maritime polar air (abbreviated mP)
Also called polar air. An air mass with characteristics developed over high latitudes, especially within the subpolar highs. Maritime polar (mP) initially possesses similar properties to those of continental polar air, but in passing over warmer water it becomes unstable with a higher moisture content.
Maritime tropical air (abbreviated mT)
Also called tropical air. An air mass with characteristics developed over low latitudes. Maritime tropical air (mT), the principal type, is produced over the tropical and subtropical seas; very warm and humid.
Maximum wind axis
On a constant pressure chart, a line denoting the axis of maximum wind speeds at that constant pressure surface.
Mean sea level
The average height of the surface of the sea for all stages of tide; used as reference for elevations throughout the U.S.
Measured ceiling
A ceiling classification applied when the ceiling value has been determined by instruments or the known heights of unobscured portions of objects, other than natural landmarks.
Mercurial barometer
A barometer in which pressure is determined by balancing air pressure against the weight of a column of mercury in an evacuated glass tube.
Meteorological visibility
In U.S. observing practice, a main category of visibility which includes the subcategories of prevailing visibility and runway visibility. Meteorological visibility is a measure of horizontal visibility near the earth’s surface, based on sighting of objects in the daytime or unfocused lights of moderate intensity at night. Compare slant visibility, runway visual range, vertical visibility. Examples are surface visibility, tower visibility, and sector visibility.
Meteorology
The science of the atmosphere.
Microbarograph
An aneroid barograph designed to record atmospheric pressure changes of very small magnitudes.
Millibar (abbreviated mb.)
An internationally used unit of pressure equal to 1,000 dynes per square centimeter. It is convenient for reporting atmospheric pressure.
Mist
A popular expression for drizzle or heavy fog.
Mixing ratio
The ratio by weight of the amount of water vapor in a volume of air to the amount of dry air; usually expressed as grams per kilogram (g/kg).
Moist-adiabatic lapse rate
Saturated-adiabatic lapse rate—The rate of decrease of temperature with height as saturated air is lifted with no gain or loss of heat from outside sources; varies with temperature, being greatest at low temperatures.
Moisture
An all-inclusive term denoting water in any or all of its three states.
Monsoon
A wind that in summer blows from sea to a continental interior, bringing copious rain, and in winter blows from the interior to the sea, resulting in sustained dry weather.
Mountain wave
A standing wave or lee wave to the lee of a mountain barrier.
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.
Mach meter
The instrument that displays the ratio of the speed of sound to the true airspeed an aircraft is flying.
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.
Mandatory altitude
An altitude depicted on an instrument approach chart with the altitude value both underscored and overscored. Aircraft are required to maintain altitude at the depicted value.
Mandatory block altitude
An altitude depicted on an instrument approach chart with two underscored and overscored altitude values between which aircraft are required to maintain altitude.
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.
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.
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.
Meridians
Lines of longitude.
Mesophere
A layer of the atmosphere directly above the stratosphere.
Microburst
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.
Military training route (MTR)
Airspace of defined vertical and lateral dimensions established for the conduct of military training at airspeeds in excess of 250 knots indicated airspeed (KIAS).
Minimum altitude
An altitude depicted on an instrument approach chart with the altitude value underscored. Aircraft are required to maintain altitude at or above the depicted value.
Minimum crossing altitude (MCA)
The lowest allowed altitude at certain fixes an aircraft must cross when proceeding in the direction of a higher minimum en route altitude (MEA).
Minimum descent altitude (MDA)
The lowest altitude (in feet MSL) to which descent is authorized on final approach, or during circle-to-land maneuvering in execution of a nonprecision approach.
Minimum drag
The point on the total drag curve where the lift-to-drag ratio is the greatest. At this speed, total drag is minimized.
Minimum en route altitude (MEA)
The lowest published altitude between radio fixes that ensures acceptable navigational signal coverage and meets obstacle clearance requirements between those fixes.
Minimum equipment list (MEL)
A list developed for larger aircraft that outlines equipment that can be inoperative for various types of flight including IFR and icing conditions. This list is based on the master minimum equipment list (MMEL) developed by the FAA and must be approved by the FAA for use. It is specific to an individual aircraft make and model.
Minimum obstruction clearance altitude (MOCA)
The lowest published altitude in effect between radio fixes on VOR airways, off-airway routes, or route segments, which meets obstacle clearance requirements for the entire route segment and which ensures acceptable navigational signal coverage only within 25 statute (22 nautical) miles of a VOR.
Minimum reception altitude (MRA)
The lowest altitude at which an airway intersection can be determined.
Minimum safe altitude (MSA)
The minimum altitude depicted on approach charts which provides at least 1,000 feet of obstacle clearance for emergency use within a specified distance from the listed navigation facility.
Minimum vectoring altitude (MVA)
An IFR altitude lower than the minimum en route altitude (MEA) that provides terrain and obstacle clearance.
Minimums section
The area on an IAP chart that displays the lowest altitude and visibility requirements for the approach.
Missed approach
A maneuver conducted by a pilot when an instrument approach cannot be completed to a landing.
Missed approach point (MAP)
A point prescribed in each instrument approach at which a missed approach procedure shall be executed if the required visual reference has not been established.
Mixed ice
A mixture of clear ice and rime ice.
Mode C
Altitude reporting transponder mode.
Moment
The product of the weight of an item multiplied by its arm. Moments are expressed in pound-inches (lb-in). Total moment is the weight of the airplane multiplied by the distance between the datum and the CG.
Moment arm
The distance from a datum to the applied force.
Moment index (or index)
A moment divided by a constant such as 100, 1,000, or 10,000. The purpose of using a moment index is to simplify weight and balance computations of airplanes where heavy items and long arms result in large, unmanageable numbers.
Monocoque
A shell-like fuselage design in which the stressed outer skin is used to support the majority of imposed stresses. Monocoque fuselage design may include bulkheads but not stringers.
Monoplanes
Airplanes with a single set of wings.
Movable slat
A movable auxiliary airfoil on the leading edge of a wing. It is closed in normal flight but extends at high angles of attack. This allows air to continue flowing over the top of the wing and delays airflow separation.
Multi-function display (MFD)
Small screen (CRT or LCD) in an aircraft that can be used to display information to the pilot in numerous configurable ways. Often an MFD will be used in concert with a primary flight display.
Buy from Amazon
