Question 1

What is radarcontrol.io?

Accepted Answer

radarcontrol.io is a free browser-based air traffic control simulator. Control aircraft by typing ATC commands or writing JavaScript scripts. 170+ real airspaces with FAA waypoint data, 300+ tower airports, SID/STAR procedures, and live METAR weather.

Question 2

Is radarcontrol.io free?

Accepted Answer

Yes, completely free. No account required to play. Create an account to save scores and compete on leaderboards.

Question 3

What does an air traffic controller do?

Accepted Answer

Controllers keep aircraft safely separated (5nm lateral or 1,000ft vertical), issue clearances for altitude/heading/speed, sequence arrivals for landing, and hand off aircraft between sectors.

Question 4

How does ATC separation work?

Accepted Answer

Controllers maintain 5nm lateral separation in en-route airspace (3nm in terminal) or 1,000ft vertical separation. Conflict alerts fire when aircraft are projected to lose separation within 2 minutes.

Question 5

What is radar separation?

Accepted Answer

Radar separation uses ATC radar to maintain minimum distances between aircraft - 5nm in en-route airspace, 3nm in terminal areas. Without radar, procedural separation uses time-based or geographic fixes instead.

Question 6

What is a flight level?

Accepted Answer

A flight level is altitude in hundreds of feet based on standard pressure (29.92 inHg). FL350 = 35,000ft. Used above 18,000ft so all aircraft reference the same pressure setting.

Question 7

What is an ATC handoff?

Accepted Answer

A handoff transfers responsibility for an aircraft from one controller to the next as it crosses sector boundaries. The receiving controller accepts the radar target and the pilot switches radio frequency.

Question 8

What is a conflict alert?

Accepted Answer

The conflict alert (CA) system detects when two aircraft are projected to lose separation. Data blocks flash on the radar display and controllers must act immediately to resolve the situation.

Question 9

What is wake turbulence?

Accepted Answer

Rotating air vortices from aircraft wingtips. Heavier aircraft produce stronger vortices. Controllers apply increased spacing: 6nm behind super/heavy aircraft. Categories: Super (A380), Heavy (B747), Medium (B737), Light.

Question 10

What are ATC clearances?

Accepted Answer

Authorization from ATC for aircraft to proceed under specified conditions. Types include altitude clearances, heading assignments, speed restrictions, approach clearances, and holding instructions.

Question 11

What is a TRACON?

Accepted Answer

A TRACON (Terminal Radar Approach Control) manages traffic near busy airports, typically below 18,000ft within about 40nm. Controllers vector arrivals to the ILS and sequence departures to the en-route structure.

Question 12

What is an ARTCC?

Accepted Answer

An ARTCC (Air Route Traffic Control Center) manages high-altitude en-route traffic. The US has 20 centers like New York Center (ZNY) and Los Angeles Center (ZLA). radarcontrol.io has all 20.

Question 13

What are airways in aviation?

Accepted Answer

Airways are the highways of the sky - published routes between navigation aids. Jet routes (J-routes) above 18,000ft, Victor routes below. Aircraft file flight plans along these routes.

Question 14

What is a SID and STAR?

Accepted Answer

A SID (Standard Instrument Departure) is a published route from a runway to the en-route airway structure. A STAR (Standard Terminal Arrival Route) brings aircraft from en-route to the airport with altitude and speed constraints at each fix.

Question 15

What is an ILS approach?

Accepted Answer

An ILS (Instrument Landing System) provides precision lateral (localizer) and vertical (glideslope) guidance for landing. The decision height is typically 200ft. In radarcontrol.io, use 'ils 27L' to clear aircraft.

Question 16

What is a holding pattern?

Accepted Answer

A racetrack-shaped path at a waypoint used to delay aircraft when arrival demand exceeds capacity. Standard holds use right turns with 4nm legs.

Question 17

What is a go-around?

Accepted Answer

When a pilot aborts a landing and climbs back to a safe altitude. Triggered by unstable approach, runway not clear, wind shear, or controller instruction. Not an emergency - a normal safety procedure.

Question 18

How are arrivals sequenced?

Accepted Answer

Controllers merge traffic from different directions onto a single approach path. Techniques include speed control, vectoring for spacing, miles-in-trail requirements, and holding patterns.

Question 19

What is a METAR?

Accepted Answer

METAR is a coded weather observation reporting wind, visibility, clouds, temperature, and pressure. radarcontrol.io uses live METAR data for runway selection at all airports.

Question 20

What is ATIS?

Accepted Answer

ATIS (Automatic Terminal Information Service) is a recorded broadcast with current airport weather, active runways, and NOTAMs. Updated hourly with a letter designation (Alpha, Bravo, etc).

Question 21

What is TCAS?

Accepted Answer

TCAS (Traffic Collision Avoidance System) is onboard equipment that independently monitors nearby aircraft and issues resolution advisories (climb/descend) to avoid collisions, even overriding ATC instructions.

Question 22

What is a squawk code?

Accepted Answer

A 4-digit transponder code assigned to each aircraft for radar identification. Emergency codes: 7500 (hijack), 7600 (radio failure), 7700 (general emergency).

Question 23

How does runway selection work?

Accepted Answer

Aircraft land and take off into the wind. Controllers select the runway with the best headwind component. Tailwind above 5 knots typically requires a runway change. radarcontrol.io uses live METAR wind data for automatic selection.

Question 24

What are fixes and navaids?

Accepted Answer

Fixes are named geographic points for navigation. Navaids (VOR, NDB, DME) are ground-based radio stations. GPS waypoints have largely replaced radio navigation, but navaids still define airway structures.

Question 25

What is the difference between ground speed and indicated airspeed?

Accepted Answer

Indicated airspeed (IAS) is what pilots fly and controllers assign. Ground speed (GS) is actual speed over the ground, affected by wind. Controllers see GS on radar but assign IAS.

Question 26

What is Mach number in aviation?

Accepted Answer

Mach number is speed as a fraction of the speed of sound. Above FL280, pilots switch from knots to Mach (e.g., M0.82) because indicated airspeed becomes unreliable in thin air.

Question 27

What is ATC phraseology?

Accepted Answer

Standardized language between controllers and pilots. Key phrases: 'climb and maintain' for altitude, 'turn left/right heading' for vectors, 'cleared ILS' for approaches. Pilots must read back all clearances to confirm understanding.

Question 28

What are NAT tracks?

Accepted Answer

North Atlantic Tracks are organized routes across the Atlantic published twice daily, optimized for jet stream winds. About 1,500 aircraft cross daily without radar coverage, using position reports and larger separation standards.

Airspaces

United States

Europe

Russia & CIS

Middle East

Asia-Pacific

Africa

Americas

Oceania

Airports

North America

Europe

Asia

Middle East

Africa

South America

Oceania

Aircraft

Interactive Commands

API Reference

Learn ATC

Core concepts

Airspace and facilities

Procedures

Aircraft performance

Weather and systems

Communication

External resources

United States

Europe

Russia & CIS

Middle East

Asia-Pacific

Africa

Americas

Oceania

North America

Europe

Asia

Middle East

Africa

South America

Oceania

Learn ATC ​

Core concepts ​

Airspace and facilities ​

Procedures ​

Aircraft performance ​

Weather and systems ​

Communication ​

External resources ​

Learn ATC

Core concepts

Airspace and facilities

Procedures

Aircraft performance

Weather and systems

Communication

External resources