Squawk codes are four-digit codes ranging from 0000 all the way through to 7777 that are set on an aircraft transponder. These unique identifiers allow air traffic control units to distinguish between different aircraft. These work with mode A, mode C, and mode S transponders.
For example, 1200 in the USA means that the flight is flying under Visual Flight Rules (VFR) and is not typically in direct contact with ATC. 1200 is a shared code so you may see many aircraft transmitting it at the same time in a given area.
Squawk 7000: This is the 'conspicuity code' for VFR aircraft that are not assigned a specific code by ATC. Squawk 2000: This is the 'conspicuity code' for IFR aircraft that are not assigned a specific code by ATC.
Transponder codesThis allows easy identification of aircraft on radar. Codes are made of four octal digits; the dials on a transponder read from zero to seven, inclusive. Four octal digits can represent up to 4096 different codes, which is why such transponders are sometimes described as 4096 code transponders.
Squawk 7000: This is the 'conspicuity code' for VFR aircraft that are not assigned a specific code by ATC. Squawk 2000: This is the 'conspicuity code' for IFR aircraft that are not assigned a specific code by ATC.
For example, 1200 in the USA means that the flight is flying under Visual Flight Rules (VFR) and is not typically in direct contact with ATC. 1200 is a shared code so you may see many aircraft transmitting it at the same time in a given area.
The most well know of these is the code 7700. This is used to indicate an emergency of any kind. A pilot will enter this when in an emergency situation - either instructed by ATC after declaring an emergency or without communication if there is no time.
The squawk code 7500 is an emergency code used by pilots to inform ATC of a plane hijacking taking place, which means that the pilots have either been forced to change course or are no longer in control of the aircraft.
Code 1400: This code is to be used when flying in controlled airspace and you are not receiving a transponder signal from ATC. Code 2000: This code indicates that the aircraft is operating in military airspace different meaning.
“Squawk 1234” means to just dial 1234 into your transponder. The ATC radar will show the controller that number in the tag associated with your plane. If the tell you, “squawk 1244 and ident”, you should put in the code first, and then press and release the Ident (or ID) button on the transponder.
This notice assigns Code 1202 for use by gliders not in contact with an air traffic control (ATC) facility. The notice also provides general flight characteristics of gliders and some of their limitations.
These emergency squawk codes are established as a worldwide standard by ICAO: 7500 - Aircraft hijacking. 7600 - Radio failure/lost communications. 7700 - General emergency - This indicates any other kind of emergency, for example, an onboard medical emergency or a mechanical problem.