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M
M-EARTS-
(See MICRO-EN ROUTE AUTOMATED RADAR TRACKING SYSTEM.)
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.)
MANDATORY ALTITUDE-
An altitude depicted on an instrument Approach Procedure Chart
requiring the aircraft to maintain altitude at the depicted value.
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.)
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 (M-EARTS)- 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- 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- 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- 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- 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. The pilot may climb immediately to the altitude specified in
the missed approach procedure.
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.
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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