Glossary

This glossary contains information on terms, phrases and abbreviations used by the Aviation industry. While this list does not include all aviation terminology, it is the purpose of this glossary to aid the general viewer in better understanding aviation terms as it pertains to content on this website. A full list of aviation terminology can be found here.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

A

Airport surveillance radar (ASR)

Approach control radar used to detect and display an aircraft’s position in the terminal area.

Airport surveillance radar approach

An instrument approach in which ATC issues instructions for pilot compliance based on aircraft position in relation to the final approach course and the distance from the end of the runway as displayed on the controller’s radar scope.

Airport/Facility Directory (A/FD)

Now part of the Chart Supplement U.S., an FAA publication containing information on all airports, communications, and NAVAIDs.

Airspeed

Rate of the aircraft’s progress through the air.

Airspeed indicator

A differential pressure gauge that measures the dynamic pressure of the air through which the aircraft is flying. Displays the craft’s airspeed, typically in knots, to the pilot.

Airway

An airway is based on a centerline that extends from one navigation aid or intersection to another navigation aid (or through several navigation aids or intersections); used to establish a known route for en route procedures between terminal areas.

Airworthiness Certificate

A certificate issued by the FAA to all aircraft that have been proven to meet the minimum standards set down by the Code of Federal Regulations.

Airworthiness Directive

A regulatory notice sent out by the FAA to the registered owner of an aircraft informing the owner of a condition that prevents the aircraft from continuing to meet its conditions for airworthiness. Airworthiness Directives (AD notes) are to be complied with within the required time limit, and the fact of compliance, the date of compliance, and the method of compliance are recorded in the aircraft’s maintenance records.

Alert area

An area in which there is a high volume of pilot training or an unusual type of aeronautical activity.

Almanac data

Information the global positioning system (GPS) receiver can obtain from one satellite which describes the approximate orbital positioning of all satellites in the constellation. This information is necessary for the GPS receiver to know what satellites to look for in the sky at a given time.

ALS

See approach lighting system.

Alternate static source valve

A valve in the instrument static air system that supplies reference air pressure to the altimeter, airspeed indicator, and vertical speed indicator if the normal static pickup should become clogged or iced over.

Altimeter

A flight instrument that indicates altitude by sensing pressure changes.

Altimeter setting

Station pressure (the barometric pressure at the location the reading is taken) which has been corrected for the height of the station above sea level.

Ambient pressure

The pressure in the area immediately surrounding the aircraft.