M
MAA-
(See MAXIMUM AUTHORIZED
ALTITUDE.)
MACH NUMBER- The ratio of
true airspeed to the speed of sound; e.g., MACH .82, MACH 1.6.
(See AIRSPEED.)
MACH TECHNIQUE [ICAO]-
Describes a control technique used by air traffic control whereby turbojet
aircraft operating successively along suitable routes are cleared to maintain
appropriate MACH numbers for a relevant portion of the en route phase of flight.
The principle objective is to achieve improved utilization of the airspace and
to ensure that separation between successive aircraft does not decrease below
the established minima.
MAHWP- Missed Approach
Holding Waypoint
MAINTAIN-
a. Concerning
altitude/flight level, the term means to remain at the altitude/flight level
specified. The phrase "climb and" or "descend and" normally precedes "maintain"
and the altitude assignment; e.g., "descend and maintain 5,000."
b. Concerning other
ATC instructions, the term is used in its literal sense; e.g., maintain VFR.
MAINTENANCE PLANNING
FRICTION LEVEL- The friction level specified in AC 150/5320-12, Measurement,
Construction, and Maintenance of Skid Resistant Airport Pavement Surfaces, which
represents the friction value below which the runway pavement surface remains
acceptable for any category or class of aircraft operations but which is
beginning to show signs of deterioration. This value will vary depending on the
particular friction measurement equipment used.
MAKE SHORT APPROACH-
Used by ATC to inform a pilot to alter his/her traffic pattern so as to
make a short final approach.
(See TRAFFIC PATTERN.)
MAN PORTABLE AIR DEFENSE
SYSTEMS (MANPADS)- MANPADS are lightweight, shoulder-launched, missile systems
used to bring down aircraft and create mass casualties. The potential for
MANPADS use against airborne aircraft is real and requires familiarity with the
subject. Terrorists choose MANPADS because the weapons are low cost, highly
mobile, require minimal set-up time, and are easy to use and maintain. Although
the weapons have limited range, and their accuracy is affected by poor
visibility and adverse weather, they can be fired from anywhere on land or from
boats where there is unrestricted visibility to the target.
MANDATORY ALTITUDE- An
altitude depicted on an instrument Approach Procedure Chart requiring the
aircraft to maintain altitude at the depicted value.
MANPADS-
(See MAN PORTABLE AIR DEFENSE
SYSTEMS.)
MAP-
(See MISSED APPROACH POINT.)
MARKER BEACON- An
electronic navigation facility transmitting a 75 MHz vertical fan or boneshaped
radiation pattern. Marker beacons are identified by their modulation frequency
and keying code, and when received by compatible airborne equipment, indicate to
the pilot, both aurally and visually, that he/she is passing over the facility.
(See INNER MARKER.)
(See MIDDLE MARKER.)
(See OUTER MARKER.)
(Refer to AIM.)
MARSA-
(See MILITARY AUTHORITY
ASSUMES RESPONSIBILITY FOR SEPARATION OF AIRCRAFT.)
MAWP- Missed Approach
Waypoint
MAXIMUM AUTHORIZED
ALTITUDE- 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, area navigation low or high route, or
other direct route for which an MEA is designated in 14 CFR Part 95 at which
adequate reception of navigation aid signals is assured.
MAYDAY- The
international radiotelephony distress signal. When repeated three times, it
indicates imminent and grave danger and that immediate assistance is requested.
(See
PAN-PAN.)
(Refer to AIM.)
MCA-
(See MINIMUM CROSSING
ALTITUDE.)
MDA-
(See MINIMUM DESCENT
ALTITUDE.)
MEA-
(See MINIMUM EN ROUTE IFR
ALTITUDE.)
MEARTS-
(See MICRO-EN ROUTE AUTOMATED
RADAR TRACKING SYSTEM.)
METEOROLOGICAL IMPACT
STATEMENT- An unscheduled planning forecast describing conditions expected to
begin within 4 to 12 hours which may impact the flow of air traffic in a
specific center's (ARTCC) area.
METER FIX ARC- A
semicircle, equidistant from a meter fix, usually in low altitude relatively
close to the meter fix, used to help CTAS/HOST calculate a meter time, and
determine appropriate sector meter list assignments for aircraft not on an
established arrival route or assigned a meter fix.
METER FIX TIME/SLOT TIME-
A calculated time to depart the meter fix in order to cross the vertex at the
ACLT. This time reflects descent speed adjustment and any applicable time that
must be absorbed prior to crossing the meter fix.
METER LIST-
(See ARRIVAL SECTOR ADVISORY
LIST.)
METER LIST DISPLAY
INTERVAL- A dynamic parameter which controls the number of minutes prior to the
flight plan calculated time of arrival at the meter fix for each aircraft, at
which time the TCLT is frozen and becomes an ACLT; i.e., the VTA is updated and
consequently the TCLT modified as appropriate until frozen at which time
updating is suspended and an ACLT is assigned. When frozen, the flight entry is
inserted into the arrival sector's meter list for display on the sector PVD/MDM.
MLDI is used if filed true airspeed is less than or equal to freeze speed
parameters (FSPD).
METERING- A method of
time-regulating arrival traffic flow into a terminal area so as not to exceed a
predetermined terminal acceptance rate.
METERING AIRPORTS-
Airports adapted for metering and for which optimum flight paths are defined. A
maximum of 15 airports may be adapted.
METERING FIX- A fix along
an established route from 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.
METERING POSITION(S)-
Adapted PVDs/MDMs and associated "D" positions eligible for display of a
metering position list. A maximum of four PVDs/MDMs may be adapted.
METERING POSITION LIST- An
ordered list of data on arrivals for a selected metering airport displayed on a
metering position PVD/MDM.
MFT-
(See METER FIX TIME/SLOT
TIME.)
MHA-
(See MINIMUM HOLDING
ALTITUDE.)
MIA-
(See MINIMUM IFR ALTITUDES.)
MICROBURST- A small
downburst with outbursts of damaging winds extending 2.5 miles or less. In spite
of its small horizontal scale, an intense microburst could induce wind speeds as
high as 150 knots
(Refer to AIM.)
MICRO-EN ROUTE AUTOMATED
RADAR TRACKING SYSTEM (MEARTS)- An automated radar and radar beacon tracking
system capable of employing both short-range (ASR) and long-range (ARSR) radars.
This microcomputer driven system provides improved tracking, continuous data
recording, and use of full digital radar displays.
MICROWAVE LANDING SYSTEM-
A precision instrument approach system operating in the microwave spectrum which
normally consists of the following components:
a. Azimuth Station.
b. Elevation
Station.
c. Precision
Distance Measuring Equipment.
(See MLS CATEGORIES.)
MID RVR-
(See VISIBILITY.)
MIDDLE COMPASS LOCATOR-
(See COMPASS LOCATOR.)
MIDDLE
MARKER- A marker beacon that defines a point along the glideslope of an ILS
normally located at or near the point of decision height (ILS Category I). It is
keyed to transmit alternate dots and dashes, with the alternate dots and dashes
keyed at the rate of 95 dot/dash combinations per minute on a 1300 Hz tone,
which is received aurally and visually by compatible airborne equipment.
(See INSTRUMENT LANDING
SYSTEM.)
(See MARKER BEACON.)
(Refer to AIM.)
MILES-IN-TRAIL- A
specified distance between aircraft, normally, in the same stratum associated
with the same destination or route of flight.
MILITARY AUTHORITY ASSUMES
RESPONSIBILITY FOR SEPARATION OF AIRCRAFT- A condition whereby the military
services involved assume responsibility for separation between participating
military aircraft in the ATC system. It is used only for required IFR operations
which are specified in letters of agreement or other appropriate FAA or military
documents.
MILITARY LANDING ZONE- A
landing strip used exclusively by the military for training. A military landing
zone does not carry a runway designation.
MILITARY OPERATIONS AREA-
(See SPECIAL USE AIRSPACE.)
MILITARY TRAINING ROUTES-
Airspace of defined vertical and lateral dimensions established for the conduct
of military flight training at airspeeds in excess of 250 knots IAS.
(See IFR MILITARY TRAINING
ROUTES.)
(See VFR MILITARY TRAINING
ROUTES.)
MINIMA-
(See MINIMUMS.)
MINIMUM CROSSING ALTITUDE-
The lowest altitude at certain fixes at which an aircraft must cross when
proceeding in the direction of a higher minimum en route IFR altitude (MEA).
(See MINIMUM EN ROUTE IFR
ALTITUDE.)
MINIMUM DESCENT ALTITUDE-
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 glideslope is
provided.
(See NONPRECISION APPROACH
PROCEDURE.)
MINIMUM EN ROUTE IFR
ALTITUDE (MEA)- The lowest published altitude between radio fixes which assures
acceptable navigational signal coverage and meets obstacle clearance
requirements between those fixes. The MEA prescribed for a Federal airway or
segment thereof, area navigation 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.
(Refer to 14 CFR Part 91.)
(Refer to 14 CFR Part 95.)
(Refer to AIM.)
MINIMUM FRICTION LEVEL-
The friction level specified in AC 150/5320-12, Measurement, Construction, and
Maintenance of Skid Resistant Airport Pavement Surfaces, that represents the
minimum recommended wet pavement surface friction value for any turbojet
aircraft engaged in LAHSO. This value will vary with the particular friction
measurement equipment used.
MINIMUM FUEL- Indicates
that an aircraft's fuel supply has reached a state where, upon reaching the
destination, it can accept little or no delay. This is not an emergency
situation but merely indicates an emergency situation is possible should any
undue delay occur.
(Refer to AIM.)
MINIMUM HOLDING ALTITUDE-
The lowest altitude prescribed for a holding pattern which assures navigational
signal coverage, communications, and meets obstacle clearance requirements.
MINIMUM IFR ALTITUDES
(MIA)- Minimum altitudes for IFR operations as prescribed in 14 CFR Part 91.
These altitudes are published on aeronautical charts and prescribed in 14 CFR
Part 95 for airways and routes, and in 14 CFR Part 97 for standard instrument
approach procedures. If no applicable minimum altitude is prescribed in 14 CFR
Part 95 or 14 CFR Part 97, the following minimum IFR altitude applies:
a. In designated
mountainous areas, 2,000 feet above the highest obstacle within a horizontal
distance of 4 nautical miles from the course to be flown; or
b. Other
than mountainous areas, 1,000 feet above the highest obstacle within a
horizontal distance of 4 nautical miles from the course to be flown; or
c. As otherwise
authorized by the Administrator or assigned by ATC.
(See MINIMUM CROSSING
ALTITUDE.)
(See MINIMUM EN ROUTE IFR
ALTITUDE.)
(See MINIMUM OBSTRUCTION
CLEARANCE ALTITUDE.)
(See MINIMUM SAFE ALTITUDE.)
(See MINIMUM VECTORING
ALTITUDE.)
(Refer to 14 CFR Part 91.)
MINIMUM NAVIGATION
PERFORMANCE SPECIFICATION- 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.
MINIMUM NAVIGATION
PERFORMANCE SPECIFICATION AIRSPACE- Designated airspace in which MNPS procedures
are applied between MNPS certified and equipped aircraft. Under certain
conditions, non-MNPS aircraft can operate in MNPSA. However, standard oceanic
separation minima is provided between the non-MNPS aircraft and other traffic.
Currently, the only designated MNPSA is described as follows:
a. Between FL 285
and FL 420;
b. Between
latitudes 27°N and the North Pole;
c. In the east, the
eastern boundaries of the CTAs Santa Maria Oceanic, Shanwick Oceanic, and
Reykjavik;
d. In the west, the
western boundaries of CTAs Reykjavik and Gander Oceanic and New York Oceanic
excluding the area west of 60°W and south of 38°30'N.
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 assures acceptable
navigational signal coverage only within 25 statute (22 nautical) miles of a VOR.
(Refer to 14 CFR Part 91.)
(Refer to 14 CFR Part 95.)
MINIMUM RECEPTION
ALTITUDE- The lowest altitude at which an intersection can be determined.
(Refer to 14 CFR Part 95.)
MINIMUM SAFE ALTITUDE-
a. The minimum
altitude specified in 14 CFR Part 91 for various aircraft operations.
b. Altitudes
depicted on approach charts which provide at least 1,000 feet of obstacle
clearance for emergency use within a specified distance from the navigation
facility upon which a procedure is predicated. These altitudes will be
identified as Minimum Sector Altitudes or Emergency Safe Altitudes and are
established as follows:
1. Minimum Sector
Altitudes. Altitudes depicted on approach charts which provide at least 1,000
feet of obstacle clearance within a 25-mile radius of the navigation facility
upon which the procedure is predicated. Sectors depicted on approach charts must
be at least 90 degrees in scope. These altitudes are for emergency use only and
do not necessarily assure acceptable navigational signal coverage.
(See ICAO term Minimum Sector
Altitude.)
2. Emergency Safe
Altitudes. Altitudes depicted on approach charts which provide at least 1,000
feet of obstacle clearance in nonmountainous areas and 2,000 feet of obstacle
clearance in designated mountainous areas within a 100-mile radius of the
navigation facility upon which the procedure is predicated and normally used
only in military procedures. These altitudes are identified on published
procedures as "Emergency Safe Altitudes."
MINIMUM SAFE ALTITUDE
WARNING- A function of the ARTS III computer that aids the controller by
alerting him/her when a tracked Mode C equipped aircraft is below or is
predicted by the computer to go below a predetermined minimum safe altitude.
(Refer to AIM.)
MINIMUM SECTOR ALTITUDE [ICAO]-
The lowest altitude which may be used under emergency conditions which will
provide a minimum clearance of 300 m (1,000 feet) above all obstacles located in
an area contained within a sector of a circle of 46 km (25 NM) radius centered
on a radio aid to navigation.
MINIMUMS- Weather
condition requirements established for a particular operation or type of
operation; e.g., IFR takeoff or landing, alternate airport for IFR flight plans,
VFR flight, etc.
(See IFR
CONDITIONS.)
(See IFR TAKEOFF MINIMUMS AND
DEPARTURE PROCEDURES.)
(See LANDING MINIMUMS.)
(See VFR CONDITIONS.)
(Refer to 14 CFR Part 91.)
(Refer to AIM.)
MINIMUM VECTORING ALTITUDE
(MVA)- The lowest MSL altitude at which an IFR aircraft will be vectored by a
radar controller, except as otherwise authorized for radar approaches,
departures, and missed approaches. The altitude meets IFR obstacle clearance
criteria. It may be lower than the published MEA along an airway or J-route
segment. It may be utilized for radar vectoring only upon the controller's
determination that an adequate radar return is being received from the aircraft
being controlled. Charts depicting minimum vectoring altitudes are normally
available only to the controllers and not to pilots.
(Refer to AIM.)
MINUTES-IN-TRAIL- A
specified interval between aircraft expressed in time. This method would more
likely be utilized regardless of altitude.
MIS-
(See METEOROLOGICAL IMPACT
STATEMENT.)
MISSED APPROACH-
a. A maneuver
conducted by a pilot when an instrument approach cannot be completed to a
landing. The route of flight and altitude are shown on instrument approach
procedure charts. A pilot executing a missed approach prior to the Missed
Approach Point (MAP) must continue along the final approach to the MAP.
b. A term used by
the pilot to inform ATC that he/she is executing the missed approach.
c. At locations
where ATC radar service is provided, the pilot should conform to radar vectors
when provided by ATC in lieu of the published missed approach procedure.
(See MISSED APPROACH POINT.)
(Refer to AIM.)
MISSED APPROACH POINT- A
point prescribed in each instrument approach procedure at which a missed
approach procedure shall be executed if the required visual reference does not
exist.
(See MISSED APPROACH.)
(See SEGMENTS OF AN
INSTRUMENT APPROACH PROCEDURE.)
MISSED APPROACH PROCEDURE
[ICAO]- The procedure to be followed if the approach cannot be continued.
MISSED APPROACH SEGMENT-
(See SEGMENTS OF AN
INSTRUMENT APPROACH PROCEDURE.)
MLDI-
(See METER LIST DISPLAY
INTERVAL.)
MLS-
(See MICROWAVE LANDING
SYSTEM.)
MLS CATEGORIES-
a. MLS Category I.
An MLS approach procedure which provides for an approach to a height above
touchdown of not less than 200 feet and a runway visual range of not less than
1,800 feet.
b. MLS Category II.
Undefined until data gathering/analysis completion.
c. MLS
Category III. Undefined until data gathering/analysis completion.
MM-
(See MIDDLE MARKER.)
MNPS-
(See MINIMUM NAVIGATION
PERFORMANCE SPECIFICATION.)
MNPSA-
(See MINIMUM NAVIGATION
PERFORMANCE- SPECIFICATION AIRSPACE.)
MOA-
(See MILITARY OPERATIONS
AREA.)
MOCA-
(See MINIMUM OBSTRUCTION
CLEARANCE ALTITUDE.)
MODE- The letter or number
assigned to a specific pulse spacing of radio signals transmitted or received by
ground interrogator or airborne transponder components of the Air Traffic
Control Radar Beacon System (ATCRBS). Mode A (military Mode 3) and Mode C
(altitude reporting) are used in air traffic control.
(See
INTERROGATOR.)
(See RADAR.)
(See TRANSPONDER.)
(See ICAO term MODE.)
(Refer to AIM.)
MODE (SSR MODE) [ICAO]-
The letter or number assigned to a specific pulse spacing of the interrogation
signals transmitted by an interrogator. There are 4 modes, A, B, C and D
specified in Annex 10, corresponding to four different interrogation pulse
spacings.
MODE C INTRUDER ALERT- A
function of certain air traffic control automated systems designed to alert
radar controllers to existing or pending situations between a tracked target
(known IFR or VFR aircraft) and an untracked target (unknown IFR or VFR
aircraft) that requires immediate attention/action.
(See CONFLICT ALERT.)
MONITOR- (When used with
communication transfer) listen on a specific frequency and stand by for
instructions. Under normal circumstances do not establish communications.
MONITOR ALERT (MA)- A
function of the ETMS that provides traffic management personnel with a tool for
predicting potential capacity problems in individual operational sectors. The MA
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.
MONITOR ALERT PARAMETER
(MAP)- The number designated for use in monitor alert processing by the ETMS.
The MAP is designated for each operational sector for increments of 15 minutes.
MOSAIC/MULTI-SENSOR MODE-
Accepts positional data from multiple radar or ADS-B sites. Targets are
displayed from a single source within a radar sort box according to the
hierarchy of the sources assigned.
MOVEMENT AREA- The
runways, taxiways, and other areas of an airport/heliport which are utilized for
taxiing/hover taxiing, air taxiing, takeoff, and landing of aircraft, exclusive
of loading ramps and parking areas. At those airports/heliports with a tower,
specific approval for entry onto the movement area must be obtained from ATC.
(See ICAO term MOVEMENT
AREA.)
MOVEMENT AREA [ICAO]- That
part of an aerodrome to be used for the takeoff, landing and taxiing of
aircraft, consisting of the maneuvering area and the apron(s).
MOVING TARGET INDICATOR-
An electronic device which will permit radar scope presentation only from
targets which are in motion. A partial remedy for ground clutter.
MRA-
(See MINIMUM RECEPTION
ALTITUDE.)
MSA-
(See MINIMUM SAFE ALTITUDE.)
MSAW-
(See MINIMUM SAFE ALTITUDE
WARNING.)
MTI-
(See MOVING TARGET
INDICATOR.)
MTR-
(See MILITARY TRAINING
ROUTES.)
MULTICOM- A mobile service
not open to public correspondence used to provide communications essential to
conduct the activities being performed by or directed from private aircraft.
MULTIPLE RUNWAYS- The
utilization of a dedicated arrival runway(s) for departures and a dedicated
departure runway(s) for arrivals when feasible to reduce delays and enhance
capacity.
MVA-
(See MINIMUM VECTORING
ALTITUDE.)
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