Skip to page content
Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The latest general information on the Coronavirus (COVID-19) is available on For FAA-specific COVID-19 resources, please visit
United States Department of TransportationUnited States Department of Transportation


AIP - Airport Improvement Program - For more information contact the appropriate FAA Airport office or reference the AIP Website.

AGL - Above Ground Level

ALP - (Airport Layout Plan) - The plan of an airport showing the layout of existing and proposed airport facilities. ALPs are used by many organizations for planning, verifying airport data, obstruction evaluation, project coordination, and other studies. They also show whether the airport meets the standards applicable to new instrument approach procedure approval.

Certified Altimeter - Altimeter that meets flight standards certification criteria for use as a altimeter setting at the airport.

Convertible Special - A special instrument flight procedure developed for a designated operator(s) according to 14 CFR 97 standards which is submitted to the FAA for conversion into a public procedure.

DA - Decision altitude: Missed approach point on a precision approach.

DH - Decision height: Missed approach point on an ILS approach.

DOT - Department Of Transportation

FAA - Federal Aviation Administration

Flight Inspection - Flight Check of Instrument Approach

FICO - Flight Inspection Central Operations

FSDO - Flight Standards District Office

GS - Glide Slope

GPS - Global Positioning System

HIRL - High Intensity Runway Lights

IFP - Instrument Flight Procedure

IAWP - In accordance with published

IFR - Instrument Flight Rules

ILS - Instrument Landing System

LAAS - Local Area Augmentation System

LIRL - Low Intensity Runway Lights

LOC - Localizer

MDA - Minimum Descent Altitude

MIRL - Medium Intensity Runway Lights

NACO - National Aeronautical Charting Office

NAS - National Airspace System

NAVAIDS - Navigational Aids

NGS - National Geodetic Survey NGS Website

NDB - Non-Directional Beacon

NFDC - National Flight Data Center

Non-Fed. Facility - A non-federally owned navigation facility that meets the requirements of Title 14 U.S.C. Part 171

Obligated Airport - Any public airport having agreements with the Federal Aviation Administration. These obligations are in the sponsor's assurances in grant agreements under the Airport Improvement Program (AIP) and in real property transfers under the Surplus Property Act and other legislation. Among the obligations is the requirement to maintain an current Airport Layout Plan on file with the FAA.

OM - Outer marker

PFC - Passenger Facility Charge

Reimbursable Agreement - Is a contract that ensures the cost recovery of goods or services provided by the FAA. Contact the appropriate FPO for further details.

RAPT - Regional Airspace Procedures Team - is an integrated team comprised of members from Air Traffic, Aviation System Standards (AVN), Flight Standards, and Airports. The RAPT evaluates customer requests that may have an impact on airspace, airports, or flight procedures.

TERPS - U.S. Standard for Terminal Instrument Procedures, FAA Order 8260.3B. The criteria used for development of most instrument flight procedures in the U.S.A.

RNAV - Area navigation

VFR - Visual Flight Rules

VGSI - Visual Glide Slope Indicator

VOR - Very high frequency Omni directional Range

WAAS - Wide Area Augmentation System

Page last modified: