List of transponder codes


The following list shows specific aeronautical transponder codes, and ranges of codes, that have been used for specific purposes in various countries. Traditionally each country has allocated transponder codes by their own scheme with little commonality across borders. The list is retained for historic interest.
Pilots are normally required to apply the code, allocated by air traffic control, to that specific flight. Occasionally countries may specify generic codes to be used in the absence of an allocated code. Such generic codes are specified in that country's Aeronautical Information Manual or Aeronautical Information Publication. There also are standard transponder codes for defined situations defined by the International Civil Aviation Organization.
Transponder codes shown in this list in the color RED are for emergency use only such as an aircraft hijacking, radio communication failure or another type of emergency.
CodeCountriesAllocated use
0000EuropeNon-discrete mode A code; shall not be used
0000UKMode C or other SSR failure
0000USShould never be assigned
0000USMilitary intercept code
0000USInternal ARTCC subsets assigned by En Route Safety and Operations Support
0021GermanyVFR squawk code for airspace and below — from 15 March 2007 replaced by the international 7000 code for VFR traffic
0022GermanyVFR squawk code for airspace above — from 15 March 2007 replaced by the international 7000 code for VFR traffic
0025GermanyParachute dropping in progress
0033UKParachute dropping in progress
0041–0057BelgiumAssigned for VFR traffic under Flight Information Services
0100AustraliaFlights operating at aerodromes
0100–0400USAllocated to Service Area Operations for assignment for use by Terminal/CERAP/Industry/Unique Purpose/Experimental Activities
0100–0700USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2
0100–0700USAlso for use in oceanic airspace, unless another code is assigned by ATC
0500, 0600, 0700USExternal ARTCC subsets
1000CanadaInstrument Flight Rules flight below 18,000' when no other code has been assigned
1000ICAONon-discrete mode A code reserved use in Mode S radar/ADS-B environment where the aircraft identification will be used to correlate the flight plan instead of the mode A code
1000USUsed exclusively by ADS-B aircraft to inhibit Mode 3A transmit
1000USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2 *Also for use in oceanic airspace, unless another code is assigned by ATC
1000USExternal ARTCC subsets
1100USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2 *Also for use in oceanic airspace, unless another code is assigned by ATC
1100USExternal ARTCC subsets
1200AustraliaCivil VFR flights in class E or G airspace
1200Canada, USVisual flight rules flight, this is the standard squawk code used in North American airspace when no other has been assigned
1201USVisual flight rules glider operations for gliders not in contact with ATC, through February 2012
1201USAssigned via FAR 93.95 for use by VFR aircraft in the immediate vicinity of LAX
1202USVisual flight rules glider operations for gliders not in contact with ATC; effective February 2012
1203–1272USDiscrete 1200 series codes, unless otherwise allocated, designated for DVFR aircraft and only assigned by FSS
1255USAircraft not in contact with an ATC facility while en route to/from or within the designated fire fighting area
1273–1275USCalibration Performance Monitoring Equipment "Parrot" transponders
1276USAir Defense Identification Zone penetration when unable to establish communication with ATC or aeronautical facility
1277USVFR aircraft which fly authorized SAR missions for the USAF or USCG while en route to/from or within the designated search area
1300USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2 *Also for use in oceanic airspace, unless another code is assigned by ATC
1300USExternal ARTCC subsets
1400CanadaVFR flight above 12,500' ASL when no other code has been assigned
1400JapanVFR flight above 10,000' MSL when no other code has been assigned
1400USExternal ARTCC subsets
1500USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2 *Also for use in oceanic airspace, unless another code is assigned by ATC
1500USExternal ARTCC subsets
1600, 1700USExternal ARTCC subsets
2000AustraliaCivil IFR flights in Class G airspace
2000CanadaUncontrolled IFR at or above 18,000ft
2000ICAO countriesThe code to be squawked when entering a secondary surveillance radar area from a non-SSR area used as Uncontrolled IFR flight squawk code
2000USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2 *Also for use in oceanic airspace, unless another code is assigned by ATC
2000USExternal ARTCC subsets
2100AustraliaGround testing by aircraft maintenance staff
2100USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2
2100USAlso for use in oceanic airspace, unless another code is assigned by ATC
2100USExternal ARTCC subsets
2200, 2300, 2400USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2
2200, 2300, 2400USAlso for use in oceanic airspace, unless another code is assigned by ATC
2200, 2300, 2400USExternal ARTCC subsets
2500, 2600, 2700USExternal ARTCC subsets
3000AustraliaCivil flights in classes A, C and D airspace, or IFR flights in Class E airspace
3000USExternal ARTCC subsets
3100, 3200, 3300, 3400, 3500, 3600, 3700USExternal ARTCC subsets
4000AustraliaCivil flights not involved in special operations or SAR, operating in Class G airspace in excess of 15NM offshore
4000USAircraft on a VFR Military Training Route or requiring frequent or rapid changes in altitude
4000USNon-discrete code assignments in accordance with FAA Order JO 7110.65, 5-2
4000USAlso for use in oceanic airspace, unless another code is assigned by ATC
4000USExternal ARTCC subsets
4100USExternal ARTCC subsets
4200, 4300USInternal ARTCC subsets assigned by En Route Safety and Operations Support
4400–4477USReserved for use by SR-71, YF-12, U-2 and B-57, pressure suit flights, and aircraft operations above FL600
4401–4433USReserved in accordance with FAA Order JO 7110.67
4434–4437USWeather reconnaissance, as appropriate
4440–4441USOperations above FL600 for Lockheed/NASA from Moffett Field
4442–4446USOperations above FL600 for Lockheed from Air Force Plant 42
4447–4452USOperations above FL600 for SR-71/U-2 operations from Edwards AFB
4453USHigh balloon operations – National Scientific Balloon Facility, Palestine TX, and other providers, some in international operations
4454–4465USAir Force operations above FL600 as designated in FAA Order 7610.4
4466–4477USReserved in accordance with FAA Order JO 7110.67
4500, 4600, 4700USInternal ARTCC subsets assigned by En Route Safety and Operations Support
5000AustraliaAircraft flying on military operations
5000US, CanadaReserved for use by NORAD
5061–5062, 5100, 5200USReserved for special use by Potomac TRACON
5100, 5200, 5300, 5500USInternal ARTCC subsets assigned by En Route Safety and Operations Support
5100–5300USMay be used by DOD aircraft beyond radar coverage but inside US controlled airspace with coordination as appropriate with applicable Area Operations Directorate
5400US, CanadaReserved for use by NORAD
5600, 5700USExternal ARTCC subsets
6000AustraliaMilitary flights in Class G airspace
6000USExternal ARTCC subsets
6100US, CanadaReserved for use by NORAD
6200, 6300USExternal ARTCC subsets
6400US, CanadaReserved for use by NORAD
6500, 6600, 6700USExternal ARTCC subsets
7000ICAOVFR standard squawk code when no other code has been assigned
7000USExternal ARTCC subsets
7000AustraliaUnmanned aerial vehicle in all classes of airspace and when instructed to enable transponder
7001FranceUsed in some countries to identify VFR traffic
7001UKSudden military climb out from low-level operations
7004UKAerobatic and display code in some countries
7100, 7200, 7300USExternal ARTCC subsets
7100, 7200, 7300Switzerland7100 in Switzerland for SAR
7400US, UK, AustraliaUnmanned aerial vehicle lost link
7500ICAOAircraft hijacking
7501–7577USReserved for use by Continental NORAD Region
7600ICAORadio failure
7601–7607USReserved for special use by FAA
7610–7676USExternal ARTCC subsets
7615AustraliaCivil flights engaged in littoral surveillance
7700ICAOEmergency
7701–7707USReserved for special use by FAA
7710–7776USExternal ARTCC subsets
7777US, Germany, Belgium, NetherlandsNon-discrete code used by fixed test transponders to check correctness of radar stations
7777USDOD interceptor aircraft on active air-defense missions and operating without ATC clearance in accordance with FAA Order 7610.4