Abbreviation/ Meaning
Acronym
LDA/PRM . . Localizer Type Directional Aid/Precision
Runway Monitor
LGA . . . . . . . LaGuardia Airport
LIRL . . . . . . . Low Intensity Runway Lights
LLWAS . . . . . Low Level Wind Shear Alert System
LLWAS NE . Low Level Wind Shear Alert System
Network Expansion
LLWAS-RS . Low Level Wind Shear Alert System
Relocation/Sustainment

LNAV . . . . . . Lateral Navigation

LOC . . . . . . . Localizer

LOP . . . . . . . Line-of-position

LORAN . . . . Long Range Navigation System

LP . . . . . . . . . Localizer Performance

LPV . . . . . . . Localizer Performance with Vertical

Guidance

LUAW . . . . . Line Up and Wait

LZ . . . . . . . . . Landing Zone

MAHWP . . . Missed Approach Holding Waypoint

MAP . . . . . . . Missed Approach Point

MAWP . . . . . Missed Approach Waypoint

MDA . . . . . . Minimum Descent Altitude

MEA . . . . . . . Minimum En Route Altitude

MEARTS . . . Micro En Route Automated Radar
Tracking System
METAR . . . . Aviation Routine Weather Report
MHz . . . . . . . Megahertz
MIRL . . . . . . Medium Intensity Runway Lights
MM . . . . . . . Middle Marker
MOA . . . . . . Military Operations Area
MOCA . . . . . Minimum Obstruction Clearance Altitude
MRA . . . . . . Minimum Reception Altitude
MRB . . . . . . . Magnetic Reference Bearing
MSA . . . . . . . Minimum Safe Altitude
MSAW . . . . . Minimum Safe Altitude Warning
MSL . . . . . . . Mean Sea Level
MTI . . . . . . . Moving Target Indicator
MTOS . . . . . . Mountain Obscuration
MTR . . . . . . . Military Training Route
MVA . . . . . . . Minimum Vectoring Altitude
MWA . . . . . . Mountain Wave Activity
MWO . . . . . . Meteorological Watch Office
NAS . . . . . . . National Airspace System
NASA . . . . . . National Aeronautics and Space
Administration
NAVAID . . . . Navigational Aid
NAVCEN . . . Coast Guard Navigation Center
NCWF . . . . . National Convective Weather Forecast
NDB . . . . . . . Nondirectional Radio Beacon

Abbreviation/ Meaning
Acronym
NEXRAD . . . Next Generation Weather Radar
NFDC . . . . . . National Flight Data Center
NGA . . . . . . . National Geospatial-Intelligence Agency
NM . . . . . . . . Nautical Mile
NMAC . . . . . Near Midair Collision
NOAA . . . . . National Oceanic and Atmospheric
Administration
NOPAC . . . . North Pacific

NoPT . . . . . . No Procedure Turn Required

NOTAM . . . . Notice to Airmen

NPA . . . . . . . Nonprecision Approach

NRS . . . . . . . Navigation Reference System

NSA . . . . . . . National Security Area

NSW . . . . . . . No Significant Weather

NTAP . . . . . . Notices to Airmen Publication

NTSB . . . . . . National Transportation Safety Board

NTZ . . . . . . . No Transgression Zone

NWS . . . . . . . National Weather Service

OAT . . . . . . . Outside Air Temperature

OBS . . . . . . . Omni-bearing Selector

ODP . . . . . . . Obstacle Departure Procedure

OIS . . . . . . . . Operational Information System

OIS . . . . . . . . Obstacle Identification Surface

OM . . . . . . . . Outer Marker
ORD . . . . . . . Chicago O'Hare International Airport
PA . . . . . . . . . Precision Approach
PAPI . . . . . . . Precision Approach Path Indicator
PAR . . . . . . . Precision Approach Radar
PAR . . . . . . . Preferred Arrival Route
PC . . . . . . . . . Personal Computer
P/CG . . . . . . . Pilot/Controller Glossary
PDC . . . . . . . Pre-departure Clearance
PFD . . . . . . . Personal Flotation Device
PinS . . . . . . . Point-in-Space
PIREP . . . . . . Pilot Weather Report
POB . . . . . . . Persons on Board
POFZ . . . . . . Precision Obstacle Free Zone
POI . . . . . . . . Principal Operations Inspector
PPS . . . . . . . . Precise Positioning Service
PRM . . . . . . . Precision Runway Monitor
PT . . . . . . . . . Procedure Turn
QICP . . . . . . Qualified Internet Communications
Provider
RA . . . . . . . . Resolution Advisory
RAA . . . . . . . Remote Advisory Airport
RAIM . . . . . . Receiver Autonomous Integrity Monitoring
STMP . . . . . . Special Traffic Management Program