sensors Mode-S transponder

4066B9

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-GDFF · BOEING 737-800

Hex
4066B9
Octal
20063271
Decimal
4,220,601
Country
GB
Tail
G-GDFF
Type
B738
Broadcasting now · callsign EXS41M · 38,000 ft
Flights observed
309
Distinct callsigns
20
Country
GB
Last broadcast
2h ago

Current position

4066B9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 4066B9 falls within the block assigned to United Kingdom (GB) by ICAO Annex 10, Volume III. Every aircraft registered in United Kingdom receives a permanent address from this block at the time of registration; the address stays with the airframe even if the aircraft is re-registered to a different operator within the country.

Callsign history 20 distinct

Callsign Airline Flights Last seen
EXS406R - 11 2026-07-12
EXS31DR - 10 2026-06-27
EXS19G - 10 2026-07-12
EXS66KE - 7 2026-06-27
EXS42UD - 7 2026-07-14
EXS27KL - 7 2026-07-14
EXS85NQ - 6 2026-07-15
EXS81TB Jet2.com 6 2026-06-27
EXS1418 Jet2.com 6 2026-06-27
EXS41M Jet2.com 5 2026-06-24
EXS9AN - 4 2026-07-13
EXS96BL - 4 2026-07-13
EXS88J - 4 2026-06-23
EXS78LQ Jet2.com 4 2026-04-20
EXS76MK - 4 2026-07-13
EXS52P - 4 2026-07-13
EXS4N Jet2.com 4 2026-04-20
EXS45NG Jet2.com 4 2026-04-19
EXS1MA - 4 2026-06-23
EXS91KB - 3 2026-06-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-15 EXS85NQ - Jul 15, 07:20 UTCJul 15, 08:45 UTC1h 25m
2026-07-14 EXS66UN XRY → STN Jul 14, 17:10 UTCJul 14, 19:35 UTC2h 25m
2026-07-14 EXS77TB - Jul 14, 13:35 UTCJul 14, 16:15 UTC2h 40m
2026-07-14 EXS42UD - Jul 14, 09:45 UTCJul 14, 12:30 UTC2h 45m
2026-07-14 EXS27KL STN → DBV Jul 14, 06:20 UTCJul 14, 08:30 UTC2h 10m
2026-07-13 EXS76MK - Jul 13, 18:15 UTCJul 13, 21:30 UTC3h 15m
2026-07-13 EXS96BL - Jul 13, 14:20 UTCJul 13, 17:00 UTC2h 40m
2026-07-13 EXS52P - Jul 13, 10:05 UTCJul 13, 12:40 UTC2h 35m
2026-07-13 EXS9AN - Jul 13, 06:30 UTCJul 13, 08:40 UTC2h 10m
2026-07-12 EXS406R - Jul 12, 19:40 UTCJul 12, 22:00 UTC2h 20m
2026-07-12 EXS19G - Jul 12, 15:25 UTCJul 12, 18:15 UTC2h 50m
2026-07-12 EXS42UD DBV → STN Jul 12, 11:25 UTCJul 12, 13:55 UTC2h 30m
2026-07-12 EXS27KL - Jul 12, 07:55 UTCJul 12, 10:10 UTC2h 15m
2026-07-11 EXS14VP HER → STN Jul 11, 21:20 UTCJul 12, 00:55 UTC3h 35m
2026-07-11 EXS7FS - Jul 11, 16:25 UTCJul 11, 19:40 UTC3h 15m
2026-07-11 EXS48CL - Jul 11, 12:35 UTCJul 11, 14:35 UTC2h 0m
2026-07-11 EXS2KC - Jul 11, 07:50 UTCJul 11, 10:00 UTC2h 10m
2026-07-11 EXS37LV - Jul 11, 00:30 UTCJul 11, 02:40 UTC2h 10m
2026-07-10 EXS82T - Jul 10, 20:50 UTCJul 10, 23:05 UTC2h 15m
2026-07-10 EXS6MT NCE → MAN Jul 10, 17:25 UTCJul 10, 19:15 UTC1h 50m
2026-07-10 EXS13Y MAN → NCE Jul 10, 13:55 UTCJul 10, 15:55 UTC2h 0m
2026-07-10 EXS29V - Jul 10, 09:55 UTCJul 10, 11:50 UTC1h 55m
2026-07-10 EXS89PK MAN → PSA Jul 10, 06:35 UTCJul 10, 08:40 UTC2h 5m
2026-07-08 EXS5R - Jul 8, 21:15 UTCJul 9, 00:50 UTC3h 35m
2026-07-08 EXS70PZ - Jul 8, 16:25 UTCJul 8, 19:30 UTC3h 5m
2026-07-08 EXS6FZ - Jul 8, 11:40 UTCJul 8, 14:45 UTC3h 5m
2026-07-08 EXS93K - Jul 8, 07:00 UTCJul 8, 09:30 UTC2h 30m
2026-07-07 EXS7FW - Jul 7, 19:40 UTCJul 8, 00:10 UTC4h 30m
2026-07-07 EXS97KT MAN → AYT Jul 7, 14:25 UTCJul 7, 18:10 UTC3h 45m
2026-07-07 EXS86WF - Jul 7, 10:30 UTCJul 7, 12:55 UTC2h 25m
2026-07-07 EXS2KC MAN → MAH Jul 7, 07:10 UTCJul 7, 09:20 UTC2h 10m
2026-07-06 EXS9DJ - Jul 6, 22:05 UTCJul 7, 00:35 UTC2h 30m
2026-07-06 EXS93G MAN → ALC Jul 6, 18:40 UTCJul 6, 21:00 UTC2h 20m
2026-07-06 EXS28YD PRG → MAN Jul 6, 15:25 UTCJul 6, 17:20 UTC1h 55m
2026-07-06 EXS4VS MAN → PRG Jul 6, 12:25 UTCJul 6, 14:10 UTC1h 45m
2026-07-06 EXS53JL - Jul 6, 08:40 UTCJul 6, 10:40 UTC2h 0m
2026-07-06 EXS15LK - Jul 6, 05:05 UTCJul 6, 06:40 UTC1h 35m
2026-07-05 EXS72YU - Jul 5, 20:25 UTCJul 5, 22:40 UTC2h 15m
2026-07-05 EXS1JK - Jul 5, 16:40 UTCJul 5, 18:35 UTC1h 55m
2026-07-05 EXS73R - Jul 5, 11:20 UTCJul 5, 15:05 UTC3h 45m
2026-07-05 EXS14CV - Jul 5, 05:55 UTCJul 5, 09:40 UTC3h 45m
2026-07-04 EXS050B - Jul 4, 12:50 UTCJul 4, 13:45 UTC55m
2026-07-03 EXS9P - Jul 3, 22:05 UTCJul 4, 02:05 UTC4h 0m
2026-07-03 EXS29JB - Jul 3, 16:25 UTCJul 3, 19:25 UTC3h 0m
2026-07-03 EXS66UN - Jul 3, 11:50 UTCJul 3, 14:15 UTC2h 25m
2026-07-03 EXS77TB - Jul 3, 08:05 UTCJul 3, 10:25 UTC2h 20m
2026-07-02 EXS92W - Jul 2, 21:35 UTCJul 3, 01:20 UTC3h 45m
2026-07-02 EXS43UN - Jul 2, 16:00 UTCJul 2, 19:55 UTC3h 55m
2026-07-02 EXS41KC MLA → STN Jul 2, 11:35 UTCJul 2, 14:35 UTC3h 0m
2026-07-02 EXS79ET - Jul 2, 07:20 UTCJul 2, 10:30 UTC3h 10m

About Mode-S

A Mode-S transponder code (also called an "ICAO 24-bit address" or "hex code") is a 6-character hexadecimal identifier permanently assigned to an aircraft when it's first registered. Unlike callsigns (which change with each flight) or registrations (which can change if an aircraft is sold internationally), the Mode-S address stays with the airframe for the life of the aircraft in that country.

Every ADS-B transmission from an aircraft includes its Mode-S address, making it the most reliable way to identify a specific airframe. Flight-tracking services like Apparatus use the Mode-S address as the primary key for tying position broadcasts, callsigns, and ownership records together.

Prefer a tail-number view? See the G-GDFF page for operator, model, and routing details .

Mode-S 4066B9 frequently asked

What is Mode-S code 4066B9?
4066B9 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-GDFF.
Where is Mode-S 4066B9 registered?
Mode-S code 4066B9 is allocated to United Kingdom (GB). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4066B9 broadcasting right now?
Yes. Mode-S 4066B9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4066B9, octal 20063271, decimal 4,220,601.
What flights does 4066B9 operate?
Mode-S 4066B9 has broadcast 20 distinct callsigns, including EXS406R, EXS31DR, EXS19G, EXS66KE, EXS42UD.