Squawk Codes List and 3 Ways to Remember Them

Squawk codes are four-digit transponder codes that help air traffic control identify aircraft on radar. A controller may assign you a discrete code, or you may use a standard code for VFR or emergency situations.

Student pilots do not need to memorize every possible code. But you should know the common ones and understand when to use them.

What a Transponder Does

A transponder responds to radar or surveillance interrogation by sending information back. Depending on the equipment, that information may include the assigned code, pressure altitude, and other aircraft data.

To the pilot, the practical task is simple: set the assigned code accurately, use altitude reporting when appropriate, and know the emergency codes.

Some panels have a VFR button, ident button, and altitude-reporting modes. Know where those controls are before you need them. During training, practice setting codes on the ground so you are not head-down for too long in flight.

Common Squawk Codes

Common codes include:

• 1200: VFR code commonly used in the United States when no other code is assigned.
• 7500: unlawful interference.
• 7600: radio communication failure.
• 7700: emergency.

In some parts of the world, VFR codes differ. Use the procedures and assignments for where you fly.

7500: Unlawful Interference

Squawk 7500 indicates unlawful interference. This is a serious code and should not be used casually or as practice in an aircraft.

If accidentally selected, correct it and communicate with ATC as appropriate. Controllers treat this code seriously because it may indicate a security threat.

7600: Radio Failure

Squawk 7600 tells ATC you have a communication failure. The failure may be transmit only, receive only, or both.

Work the problem: volume, squelch, frequency, audio panel, headset plugs, microphone, circuit breakers if appropriate, and alternate radio if installed.

If you can hear ATC but cannot transmit, they may ask you to ident or change codes to answer questions. If you cannot hear or transmit, follow the lost-communication procedures appropriate to the flight and airspace.

Near a towered airport, watch for light gun signals.

7700: Emergency

Squawk 7700 indicates an emergency. It may be used for engine failure, fire, severe icing, medical emergency, fuel emergency, flight control problem, or another distress or urgency condition.

If you have time, communicate with ATC. A useful structure is NITS:

• Nature of the problem.
• Intentions.
• Time or fuel remaining.
• Special requests.

Example: "Mayday, Cessna 123AB, engine failure, five miles west of the airport, landing in a field, two souls on board, one hour fuel."

Fly the airplane first. The code helps ATC help you, but it does not replace aircraft control.

If you are already talking to ATC, they may assign or suggest a code. If you are not talking to anyone and need help, setting 7700 can make the emergency visible. Use judgment and follow procedures appropriate to the situation.

Three Memory Tips

First, remember the sequence: 7500, 7600, 7700. Security, communication, emergency.

Second, use a plain sentence: "Hijack, can't talk, emergency." That maps to 7500, 7600, and 7700.

Third, use ICE: interference, communication, emergency.

Use whatever memory aid works, but practice recalling the codes under light pressure. Emergencies are not the time to search your memory slowly.

Student-Pilot Habit

When assigned a squawk code, read it back, set it carefully, and verify it. Four digits can be easy to transpose.

When changing from an assigned code to VFR or an emergency code, be deliberate. Your transponder is part of how ATC builds a picture of the sky.

Know the codes, but more importantly, know the situation that makes each one appropriate.

Do not practice emergency squawks in flight unless specifically directed in an appropriate training context. For normal practice, use cockpit discussion, chair flying, or simulator work.

Code Changes Need Verification

After entering any code, look again and verify all four digits. A single wrong digit can prevent ATC from seeing the intended information. This is especially important during workload spikes, when your hand may move faster than your brain.

If ATC says "squawk ident," press the ident button once and leave the assigned code alone unless instructed otherwise.

When receiving flight following, expect ATC to assign a discrete code. Keep that code until ATC tells you to change it, cancel radar service, or squawk VFR. Changing early can make your target harder to identify.

Related Reading

For equipment and airspace context, read FAA Transponder Requirements Explained. For a broader avionics overview, review Transponder Modes Explained.

Official References

• FAA AIM 4-1-20 Transponder Operation
• FAA AIP ENR 1.1 General Rules
• FAA Aeronautical Information Manual
• 14 CFR Part 91 General Operating Rules
• FAA Aeronautical Chart User's Guide