Aeronautical Terms beginning with A

A.C.

Alternating Current.

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A/FD

Airport/Facility Directory—obsolete. Changed to Chart Supplement.

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ADF

Automatic Direction Finder.

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ADI

Attitude Director Indicator.

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ADM

Aeronautical Decision-Making.

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ADSB

Automatic Dependent Surveillance Broadcast.

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AIRMET

Inflight weather advisory issued as an amendment to the area forecast, concerning weather phenomena of operational interest to all aircraft and that is potentially hazardous to aircraft with limited capability due to lack of equipment, instrumentation, or pilot qualifications.

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ALS

Approach Lighting System.

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AME

Aviation Medical Examiner.

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ARSR

Air Route Surveillance Radar.

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ARTCC

Air Route Traffic Control Center.

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ASDE

Airport Surface Detection Equipment.

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ASOS

Automated Surface Observing Station.

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ASR

Airport Surveillance Radar.

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ATC

Air Traffic Control.

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ATCRBS

Air Traffic Control Radar Beacon System.

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ATIS

Automatic Terminal Information Service.

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AWOS

Automated Weather Observing System.

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