Air Traffic Control Communication Systems

The primary method for communication between pilots and air traffic controllers in the U.S. air traffic control system.

The international language designated by the International Civil Aviation Organization (ICAO) for air traffic control (ATC) communications worldwide.

A set of standardized words and phrases used in air traffic control communications to ensure clarity and prevent misunderstandings.

Any deviation from the standard terms and phrases established by ICAO or FAA.

To ensure safe and efficient air traffic control operations, communication between pilots and controllers must be reliable and accurate.

The system designed to manage the flow of air traffic, providing separation and guidance to aircraft.

Procedures and guidelines for separating and assisting aircraft in the air traffic control system.

The safe operation of the nation’s air traffic control system is reliant on effective communication between pilots and air traffic controllers.

A type of radio communication where the controller can transmit to the pilot, but the pilot cannot transmit back.

A type of radio communication where both the controller and pilot can transmit and receive.

Radio equipment that allows the transmission and reception of radio signals.

The early use of navigation aids (navaids) for communication in air traffic control.

A method of radio communication where the controller transmits on a different frequency from the one used for navigation.

The problem encountered during the transition to duplex communication where aircraft without transceivers were unable to communicate with control towers.

A temporary solution that allowed aircraft to communicate with control towers using a separate set of radios while still relying on navaids for navigation.

The system that uses ground-based navaids for tower-to-aircraft communication and separate radios for aircraft-to-tower communication.

The ability for the pilot to receive navigation signals while the controller transmits communication instructions.

The time at the Greenwich Observatory in England, used as a universal reference point for timekeeping.

Converting local time to UTC involves adding the time difference from the UTC time zone.

Converting UTC to local time involves subtracting the time difference from the UTC time zone

A standard atmospheric pressure used to adjust aircraft altimeters for accurate altitude readings.

Issued by air traffic control to indicate the current standard atmospheric pressure for altimeter adjustments.

The altimeter setting should be announced clearly and precisely, individually enunciating each digit without pronouncing the decimal point.

Expressing time in a 24-hour format, where 0000 represents midnight and 2359 represents 11:59 pm.

Converting from local time to UTC requires converting the local time to a 24-hour clock format.

The controller should enunciate each digit of the time individually and clearly, using the 24-hour clock format.

Adding the suffix “zulu” to any UTC time announcement signals that the time is UTC.

Pilots from countries using the metric system measure barometric pressure in millibars, instead of inches of mercury.

It's the responsibility of the pilot to convert the altimeter setting to millibars or request a metric setting from air traffic control.

Wind direction at airports is referenced to magnetic north, indicating the direction the wind is blowing from.

Wind direction is rounded to the nearest 10 degrees.

A wind from the east is a 90-degree wind, and a wind from north to south is a 360-degree wind.

The international standard for measuring wind velocity is knots, approximately 1.15 miles per hour.

Wind information is always preceded by the word 'wind,' followed by the direction in degrees and then 'at' and the velocity in knots.

If wind measurement devices are inoperative, the information is preceded by 'estimated.'

If the wind direction is constantly changing, 'variable' is added to the average direction.

If the wind velocity is constantly changing, 'gusts' and the peak speed are added to the wind speed.

In radio communication, the third digit after the decimal point is typically assumed to be either 0 or 5 and is not pronounced.

For VHF and UHF frequencies, the decimal point is pronounced as "point".

Radio frequencies within the L/MF range (low/medium frequency) are usually followed by the word 'kilohertz'.

The International Civil Aviation Organization (ICAO) recommends using the word 'decimal' instead of 'point' when pronouncing frequencies.

Microwave landing system (MLS) and TACAN channels are referred to by their channel number, not a specific frequency.

Air traffic control communications should always measure speed in knots, not miles per hour, especially for aircraft using airspeeds in miles per hour.

An airspeed in miles per hour is about 15% higher than the equivalent airspeed in knots.