ATC Glossary

Definitions for common ATC terms


active runway
The runways to which you'll be cleared for takeoffs and landings by ATC. In Flight Simulator

you can select a different active runway at airports with multiple runways. Active runways are the runways most closely aligned with the wind.

advisory (frequency)
In Flight Simulator, similar to common traffic advisory frequency (CTAF). Pilots use the advisory frequency at nontowered airports to let other air traffic know they are on approach or taking off.

Airport/Facility Directory
A United States government publication that provides information about airports and navigation facilities. Use the A/FD to get information about radifrequencies, runways, instrument approaches, layout of airports, and other details. A/FDs can be purchased at most pilot supply stores.

Designated volumes of space that determine whether and by which controlling agency a particular area is controlled.

altimeter setting
The local barometric pressure reading dialed into the Kollsman window of an altimeter. The setting can be obtained from the automated weather services in Flight Simulator, and is read to the pilot by ATC in some instances.

approach control
An air traffic controller that directs aircraft in and out of congested areas. Approach usually handles traffic between the tower-controlled and center-controlled phase of flight. Approach controllers frequently handle departing as well as arriving flights.

The Air Route Traffic Control Centers direct aircraft between the phases of IFR flight controlled by departure and arrival controllers. They may also handle VFR traffic on Flight Following.

ASOS (Automated Surface Observation System)
A continuously updated (minute-by-minute) automated weather briefing system used at some United States airports. For more on ASOS, see Airport ATC Operations.


In airport traffic patterns, a pattern leg at right angles to the landing runway. Base leg connects the downwind leg to the extended runway centerline.


call sign
The identification that ATC and a pilot use for a particular flight or aircraft. Call signs are generally a combination of the aircraft type or manufacturer and the aircraft registration for civilian planes, a combination of the airline and flight number for airline flights, and a combination of branch of service and flight number for military flights. Call signs should always be included in any communication with ATC to avoid confusion about who's talking.

clearance delivery
Clearance delivery issues IFR clearances. A clearance is necessary before departing on an instrument flight plan.

closed traffic
A landing during which the pilot doesn't let the aircraft come to a complete stop before applying power and taking off again. This is often done to practice takeoffs and landings. Also known as touch and go.

In airport traffic patterns, a pattern leg at right angles to the landing runway off the departure end.


departure control
Departure control directs aircraft out of congested traffic areas. Departure usually handles traffic between the tower-controlled and center-controlled phase of flight. Departure controllers frequently handle arriving as well as departing flights.

The direction the wind is blowing. In airport traffic patterns, downwind refers to the pattern leg flown parallel to the runway in the direction the wind is blowing (opposite to the direction of landing).

DPs (departure procedures)
DPs are published procedures for departing a particular airport on an instrument flight plan. ATC in Flight Simulator does not include DPs in IFR clearances.



In airport traffic patterns, the pattern leg directly along the extended runway centerline.

flight following
A radar service for VFR aircraft that provides traffic advisories when the controller isn't too busy. It's a useful service when pilots are flying cross-country and may have to transition through multiple controllers' airspaces, as they don't have to request a transition from each controller along the way and can get traffic advisories.

flight plan
In Flight Simulator, flight plans refer to IFR flights. You can create a flight plan in the Flight Planner, and ATC will clear you along that route. VFR routes can be planned using the Flight Planner, but ATC does not use the routing

information in VFR plans for any communication during the flight.

flight level
In the United States, pilots flying above 18,000 feet (5,486 meters) are required to set the digits in the altimeter's Kollsman window to 29.92. The resulting altimeter reading is called a flight level. When the Kollsman window is set to 29.92 (1013.2 millibars) and the altimeter reads 30,000 feet, the altitude is stated as, "Flight Level 300 (three zero zero)."

Flight Planner
The Flight Planner is used to create IFR flight plans and for planning routes for VFR flights. You can access the entire airport database in Flight Simulator through the Flight Planner. To learn more about using this feature, see Using the Flight Planner.

FSS (flight service station)
Air traffic facilities that provide a variety of services to pilots. In Flight Simulator, remote IFR clearances at airports without clearance delivery are given on FSS frequencies.

full-stop landing
A landing that includes a complete stop on the runway, or when the aircraft leaves the runway on the ground before taxiing back for another takeoff.


ground control
Ground control directs aircraft traffic between parking and the runway.


hold short
When a ground or tower controller wants an aircraft to stop at a certain location while taxiing, the controller will tell the pilot to "hold short." This is usually in reference to a runway. The entire instruction is, "Hold short of runway X," where X is the runway number.


IFR (instrument flight rules)
Rules governing flights conducted under instrument meteorological conditions (flights conducted below VFR minimums).

IFR clearances
An IFR clearance is issued by clearance delivery prior to departure. The clearance includes information about the route of flight, altitude to be flown, and the radio frequency

for the departure controller.

ILS (instrument landing system)
A precision approach system that includes a glide slope, localizer, marker beacons, and airport lighting.

instrument rated
Pilots who have received the required IFR training and have passed both written and practical exams are awarded an instrument rating. They can then fly in weather conditions during which they fly by reference to the cockpit instruments.





missed approach
Declaration by a pilot on an instrument approach that he has reached the point designated as a missed approach point without seeing the runway or airport lighting. Declaring a missed approach also signals the pilot's intent to execute the published missed approach procedure.

Mode C transponder
A transponder is a transmitter/receiver that returns a signal when interrogated by a signal from the ground. When a pilot dials a particular code into the transponder, that code shows up on controllers' radar screens next to the aircraft's radar image. Mode C provides the aircraft's altitude to the controller as well.




parking gate
In Flight Simulator, parking gates are attached to airport terminal buildings.

parking spot
In Flight Simulator, parking spots are usually located in open areas on the airport.

progressive taxi
Progressive directions from a ground controller to a pilot to assist the pilot in navigating between parking and the runway. In Flight Simulator, Progressive Taxi draws a line from the user's current aircraft location to a runway or parking spot. Request progressive taxi using the ATC menu.

The act of being pushed back from an airport terminal gate. This is usually done by hooking a small tug to the nose wheel of a large aircraft and pushing it backwards into the taxi lane. In Flight Simulator, press SHIFT+P to push back from the gate.



radar contact
Acquisition of the radar image of a particular aircraft by the controller. A controller issues a transponder code to a pilot, and the pilot sets the code into the transponder. When the controller sees the image of that aircraft on the radar screen, she advises the pilot she has radar contact.


Terminology used by air traffic controllers to request a pilot to set a specific code into the transponder radio.

STARs (standard terminal arrival routes)
Published procedures for particular airports to get a flight from the en route to the approach phase of flight. Flight Simulator ATC does not include STARs in IFR approach clearances.


Avenues by which aircraft get to and from the runway at airports. By using a taxiway, the pilot avoids conflicts with other aircraft on the runway.

The building through which arriving and departing passengers pass when getting onto or off of aircraft at an airport. Parking gates in Flight Simulator are attached to terminals.

touch and go
A landing during which the pilot doesn't let the aircraft come to a complete stop before applying power and taking off again. This is often done to practice takeoffs and landings. Also known as closed traffic.

tower control
The controllers in the tall towers at airports direct the air traffic within the airport traffic area. Takeoffs and landings are done under their control as well as transitions through their airspace.

To cross through controlled airspace. In Flight Simulator, you can request clearance from ATC to transition through controlled airspace. The ATC menu includes requests for transitions when you are heading toward airspace for which a transition is appropriate.

A cockpit receiver/transmitter that receives signals from ground-based radar and transmits a specific code back to the ground-based equipment. This allows air traffic controllers to identify specific aircraft moving across their radar screens.


In airport traffic patterns, a pattern leg parallel to the landing runway in the direction opposite the wind.


Directions given by a controller to pilots to position them for an approach or to avoid other aircraft. The directions include the direction in which pilots should turn (left or right) and the new compass heading they should fly.

"Cessna 28T, turn right heading 270."

VFR (visual flight rules)
Below are the United States Federal Aviation Regulations regarding VFR minimums. FAR 91.155: Basic VFR Weather Minimums


Except as provided in paragraph (b) of this section and Sec. 91.157, no person may operate an aircraft under VFR when the flight visibility is less, or at a distance from clouds that is less, than that prescribed for the corresponding altitude and class of airspace in the following table:

Airspace Visibility Clouds
Class A Not applicable Not applicable
Class B 3 statute miles Clear of clouds
Class C 3 statute miles 500 feet below; 1,000 feet above; 2,000 feet horizontal
Class D 3 statute miles 500 feet below; 1,000 feet above; 2,000 feet horizontal
Class E
Less than 10,000 feet MSL
3 statute miles 500 feet below; 1,000 feet above; 2,000 feet horizontal
Class E
At or above 10,000 feet MSL
5 statute miles 1,000 feet below; 1,000 feet above; 1 statute mile horizontal

VHF radio
Very high frequency radio range used for aircraft communication and navigation.

The ability to see and identify prominent unlighted objects by day and prominent lighted objects by night. Visibility is reported by weather services as statute miles, hundreds of feet, or meters.

visual approach
An IFR approach that authorizes the pilot to continue visually and clear of clouds to the airport. The pilot must, at all times, have either the airport or the preceding aircraft in sight. The approach must be authorized by and under the control of the appropriate air traffic control facility. Weather at the airport must include a reported ceiling at or above 1,000 feet and visibility of three miles or greater.