AIM Aeronautical Information Manual
ALS Approach Light System
ALSF-I Approach Light System with sequenced Flashing
Lights
ALSF-II ALS with sequenced flashing lights and red
side row lights the last 1,000 ft.
ASOS Automated Surface Observing System.
ATC Air Traffic Control
ATIS Automatic Terminal Information Service
ATP Airline Transport Pilot
AWOS Automated Weather Observing Station
AWOS-1 Reports altimeter setting, wind data,
temperature, dew point, and density altitude.
AWOS-2 All of the reports as in AWOS-1 plus
visibility.
AWOS-3 the same as AWOS-2 plus cloud/ceiling data.
CAT Clear air turbulence
Ceiling the height above the earth’s surface of the
lowest layer of clouds or obscuring phenomena that are reported as broken
overcast or obscuration.
CL Centerline light
DA Decision Altitude
DH Decision Height
DME Distance Measuring Equipment
ETA Estimated time of arrival
ETE Estimated Time Enroute
FAA Federal Aviation Administration
FAF Final Approach Fix
FAP Final Approach Point
FAR Federal Aviation Regulation
FL Flight Level
Grid MORA grid minimum off-route altitude
The GRID MORA altitude provides terrain and altitude
clearance within the section outlined by latitude and longitude lines.
GS Ground speed
GS Glide slope
GSIA Glide Slope Intercept Altitude
HAT Height above touchdown
HIRL High-intensity Runway Light System
IAF Initial Approach Fix
ICAO International Civil Aviation Organization
IFR Instrument Flight Rules
ILS Instrument Landing System
J-route Jet routes designated on high altitude enroute
navigation charts.
L/D Ratio Lift to drag ratio.
LOC Localizer
M Symbol for the missed approach point on Jeppesen
approach plates.
MAA Maximum authorized altitude.
Mach number This is the ratio of true airspeed to the
speed of sound.
MAP Missed approach point.
MCA Minimum Crossing Altitude This is the lowest
altitude at certain fixes at which an aircraft must cross.
MDA Minimum descent altitude.
MEA gap Established on enroute charts to denote a gap
in nav-signal coverage.
MEA minimum enroute IFR altitude The lowest published
altitude between radio fixes which assures acceptable navigational signal
coverage and meets obstacle clearance requirements between those fixes.
METAR aviation routine weather report.
MM Middle marker
MOCA Minimum Obstruction Clearance Altitude The lowest
published altitude in effect between radio fixes on VOR airways, off airway
routes, or route segments which meet obstacle clearance requirements for the
entire route segment and which assures acceptable navigational signal coverage
only within 22 nautical miles of a VOR.
MRA Minimum reception altitude The lowest altitude at
which an intersection can be determined.
MSA Minimum safe altitude 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.
MSL Mean sea level
MVA minimum vectoring altitude: The lowest altitude at
which an IFR aircraft will be vectored by radar controller.
NM Nautical mile
NoPT No procedure turn authorized
NOTAM Notices to airmen
OPSSPECs. Operations specifications.
PAPI Precision approach path indicator
PDP Planned descent point
QFE Height above airport elevation or runway threshold
elevation based on local station pressure.
QNE Altimeter setting 29.92 inches of mercury or 1013.
Hectopascals or millibars.
QNH Altitude above mean sea level based on local
station pressure.
RAs Resolution alert.
RCLM Runway centerline markings
Route MORA minimum off-route altitude The Route MORA
altitude provides reference point clearance within 10NM of the route centerline.
Route MORA values clear all reference points by 1,000
feet in areas where the highest reference points are 5,000 feet MSL or lower.
Route MORA values clear all reference points by 2,000
feet in areas where the highest reference points are above 5,000 feet MSL.
RVR Runway visual range, it is measured from the
touchdown zone area.
RVRNO RVR information not available.
SA Surface analysis weather report.
SLPNO Sea Level Pressure information not available.
TAF Terminal area forecast.
TAs Traffic alerts
TAS True air speed
TCAS Traffic alert and collision avoidance system TCAS
I provides proximity warning only. No recommended avoidance maneuvers are
provided nor authorized as a direct result of a TCAS I warning.
TCAS II Provides traffic advisories TAs and resolution
advisories RAs. RAs provide recommended maneuvers in vertical direction only to
avoid conflicting traffic.
TCAS III TCAS III provides features of TCAS II plus
RAs in a horizontal direction to avoid conflicting traffic.
TCH Threshold crossing height
TDZL Touchdown zone lights
TERP United States standard for terminal Instrument
procedures
TIT Turbine inlet Temperature
TR Transformer-rectifier
V1 Maximum speed in the takeoff at which the pilot
must take the first action (apply brakes, reduce thrust, deploy speed brakes)
to stop the airplane within the accelerate-stop distance.
V1 also means the minimum speed in the takeoff
following a failure of the critical engine VEF at which the pilot can continue
the takeoff and achieve the required height above the takeoff surface within
the takeoff distance.
V2 Takeoff safety speed a referenced airspeed obtained
after lift-off at which the required one-engine inoperative climb performance
can be achieved.
VA Design maneuvering speed.
VASI Visual approach slope indicator
VB Design speed for maximum gust intensity.
VEF The speed at which the critical engine is assumed
to fail during takeoff
VDP Visual descent point
VHF Very high frequency
VLE Maximum landing gear extended speed
VLO Maximum landing gear operating speed
VMC Minimum control speed with the critical engine
inoperative.
VMO/MMO Maximum operating limit speed
VOR VHF omnidirectional range
VR Rotation speed