FLYSCOUTSquawk codes list: what 7000, 2000, 1200 and the emergency codes mean
A squawk code is the four-digit number an aircraft's transponder sends to radar. Most are assigned by air traffic control for one flight; a few have fixed meanings. Three mean the same everywhere, 7700 for an emergency, 7600 for a radio failure and 7500 for a hijack, while codes such as 7000, 2000 and 1200 depend on where you are.
The squawk is the simplest identity an aircraft's transponder sends: four digits that air traffic control asks the crew to set. Today it sits alongside the aircraft's callsign and its 24-bit address, but controllers still use it, and a few codes carry a fixed meaning that anyone watching a flight tracker can read.
How squawk codes work
A squawk is four digits, each from 0 to 7, which gives 4,096 possible codes. Air traffic control normally gives each flight its own code for the time it is under that controller, a discrete code, so the radar can tell it apart from every other aircraft. Codes ending in 00 are non-discrete: there are 64 of them, and they say something general about an aircraft rather than which one it is. Beyond the emergency codes, what a code means can differ from country to country.
The codes that mean the same everywhere
| Code | Meaning |
|---|---|
| 7700 | Emergency |
| 7600 | Radio failure |
| 7500 | Unlawful interference, such as a hijack |
These three are reserved worldwide and set off alarms on controllers' screens. When pilots change from one code to another, they avoid passing through them, so that no alarm goes off by accident. More in what does squawk 7700 mean.
Common codes in Europe
Under the rules of the air used across Europe and in the UK:
| Code | Meaning |
|---|---|
| 2000 | No instruction from air traffic control, for example on entering from airspace where transponders are not required |
| 7000 | Flying without an air traffic service, set so that radar and other aircraft can see it (conspicuity) |
| 1000 | Instrument flights by Mode S aircraft identified by the callsign they send, so they need no discrete code |
Codes in the UK
The UK publishes its full list of code allocations. Some of the fixed ones, from the list in force since 3 September 2026:
| Code | Meaning in the UK |
|---|---|
| 0000 | Transponder data unreliable |
| 0020 | Air ambulance helicopter |
| 0023 | Search and rescue |
| 0024 | Radar flight evaluation and calibration |
| 0030 | Lost (FIR lost) |
| 0032 | Police air support |
| 0033 | Parachute dropping, from 5 minutes before the drop until it is complete |
| 2000 | Entering UK airspace from an area where transponders are not required; instrument flights with no service or code; Mode S aircraft parked or under tow |
| 7000 | Visual flights, for conspicuity |
| 7001 | Military fast jets entering the low flying system |
| 7002 | Flying in a danger area |
| 7003 | The Red Arrows |
| 7004 | Aerobatics and displays, from 5 minutes before |
| 7005 | Military fast jets flying high-energy manoeuvres |
| 7006 | Military aircraft operating on their own in reserved airspace |
| 7007 | Open Skies treaty observation flights |
| 7010 | Flying circuits at an airport, when air traffic control or local procedures say so |
| 7400 | Unmanned aircraft that has lost its control link |
UK pilots flying near some busy airports without talking to them also set a "listening squawk", which tells controllers they are listening on the frequency and can be called: 7012 near Gatwick, 0013 near Luton, 7013 near Stansted and 7366 near Manchester, for example.
A few numbers mean something else in the UK than elsewhere. 1200, the US code for visual flights, is allocated in the UK to the Ministry of Defence's Air Command, and 4000 to NATO aircraft working with airborne early warning aircraft.
Codes in the US
The FAA's list includes:
| Code | Meaning in the US |
|---|---|
| 1200 | Visual flight rules, at any altitude |
| 1202 | Gliders under visual flight rules |
| 1255 | Firefighting aircraft not in contact with air traffic control |
| 1277 | Visual search and rescue flights |
| 4000 | Military aircraft in restricted or warning areas, and flights with frequent changes of height, such as flight tests and air refuelling |
| 7400 | Unmanned aircraft that has lost its control link |
| 7777 | Military interceptor operations only, never civil aircraft |
In Canada, 1000 has yet another meaning: instrument flights below 18,000 ft.
Seeing squawk codes on a flight tracker
Most trackers show an aircraft's squawk in its details, though some keep it for paying users. Flightradar24 turns aircraft squawking 7700 or 7600 red on its map. ADS-B Exchange can filter its map by code, which is a quick way to find, say, every aircraft squawking 7000 near you, or every police helicopter on 0032 in the UK.
FlyScout watches the three emergency codes worldwide: an aircraft squawking 7700, 7600 or 7500 becomes a finding, and FlyScout follows it to its landing. See how to track emergency flights.
Questions people ask
What does squawk 7000 mean?
In the UK and across Europe, 7000 is the code a pilot sets when flying under visual flight rules without an air traffic service, so radar can see the aircraft. In the US, the equivalent code is 1200.
What does squawk 2000 mean?
In Europe, 2000 is the code an aircraft sets when it has no instruction from air traffic control, for example when entering controlled airspace from an area where transponders are not required. In the UK it is also used by Mode S aircraft parked or under tow on the ground.
What does squawk 1200 mean?
In the US, 1200 is the code for an aircraft flying under visual flight rules, at any altitude, without an assigned code. The UK uses 7000 for that and allocates 1200 to the Ministry of Defence.
How many squawk codes are there?
4,096. Each of the four digits runs from 0 to 7, because the code is sent as octal numbers. The 64 codes ending in 00 are called non-discrete; the rest are discrete codes that controllers can give to one aircraft at a time.
Can a squawk code tell you what an aircraft is doing?
Sometimes. Fixed codes mark aircraft doing particular jobs, such as parachute dropping, police flights or aerobatics in the UK, or military aircraft in restricted areas in the US. Most of the time, though, an airliner's code is just a label for that flight.
Sources
- SKYbrary: Discrete and non-discrete SSR codes
- UK CAA: SERA.13005, SSR transponder Mode A code setting
- NATS: UK SSR code allocation list, digital dataset (effective 3 September 2026)
- FAA: Aeronautical Information Manual, chapter 4, section 1 (transponder operation)
- FAA: Order JO 7110.65, chapter 5, section 2 (beacon systems)
- FAA: Aeronautical Information Manual, chapter 6, section 3 (distress and urgency procedures)