Air Traffic Control and Communication: Radar, Radios, Weather, and Procedures

Radar

A system that uses radio waves to detect objects and determine their direction and distance.

Range

The measure of how far away a radar target is, determined by the time delay between signal transmission and reception.

Echo

The reflected radio energy that returns to the radar antenna after hitting an aircraft.

Azimuth/Bearing

The direction of a target determined by the pointing direction of the radar's antenna at the moment an echo is received.

Primary Surveillance Radar (PSR)

Radar that detects aircraft using reflected energy without requiring on-board equipment.

Secondary Surveillance Radar (SSR)

Radar that relies on aircraft carrying a transponder that responds to ground interrogation.

Clutter

Reflections from ground, sea, or structures that can mask or interfere with radar detection.

Line-of-Sight Limitations

Obstructions caused by the Earth's curvature or terrain that can block radar returns at low altitudes.

Transponder

An aircraft device that responds to SSR interrogations by transmitting a coded reply.

Pressure Altitude

The altitude reported by a transponder based on atmospheric pressure.

Mode A

Transponder mode that returns an aircraft's identity code.

Mode C

Transponder mode that returns pressure altitude along with the identity code.

Mode S

Transponder mode that supports selective addressing and returns advanced data.

ATC

Air Traffic Control—responsible for directing aircraft movements in the air and on the ground.

Sequencing

The process of managing the order and spacing of arrivals and departures in the terminal area.

Radar Vector

A heading instruction given to guide an aircraft onto a desired path for approach or spacing.

Situational Awareness

The ability of controllers to integrate multiple sources of information for effective air traffic management.

METAR

A routine aviation weather report that provides current weather conditions at an airport.

TAF

A terminal aerodrome forecast that describes expected weather conditions over a specified period.

VHF (Very High Frequency)

Radio frequencies ranging from 30 MHz to 300 MHz, primarily used for civilian aviation communication.

UHF (Ultra High Frequency)

Radio frequencies ranging from 300 MHz to 3000 MHz, commonly used in military aviation.

Readback

When a pilot repeats back a clearance received from ATC to confirm understanding.

Light Gun Signals

Visual communication signals used by ATC when radio contact is not possible.

Lost Communication (Lost Comm)

The situation where two-way radio communication between an aircraft and ATC cannot be established or maintained.

Transponder Code $7600$

The code squawked by an aircraft to indicate lost communication status.

Ground Movement Control

The process of managing aircraft taxi routes, runway crossings, and apron operations.

Clearance Delivery

The process through which ATC provides the pilot with permission to proceed and/or instructions for departure.

Holding Pattern

A predefined racetrack flight maneuver designed to keep an aircraft in a specified airspace.