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sensors Mode-S transponder

403321

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-BSYY · PIPER PA-28-140/150/160/180

Hex
403321
Octal
20031441
Decimal
4,207,393
Country
GB
Tail
G-BSYY
Type
P28A
No current signal · last broadcast 12h ago
Flights observed
103
Distinct callsigns
1
Country
GB
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S 403321.

Country allocation

The ICAO 24-bit address 403321 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 1 distinct

Callsign Airline Flights Last seen
GBSYY - 103 2026-07-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-18 GBSYY - Jul 18, 09:10 UTCJul 18, 09:35 UTC25m
2026-07-15 GBSYY - Jul 15, 13:30 UTCJul 15, 13:40 UTC10m
2026-07-15 GBSYY - Jul 15, 12:10 UTCJul 15, 13:25 UTC1h 15m
2026-07-09 GBSYY - Jul 9, 17:40 UTCJul 9, 18:20 UTC40m
2026-07-09 GBSYY - Jul 9, 13:10 UTCJul 9, 13:45 UTC35m
2026-07-09 GBSYY - Jul 9, 10:30 UTCJul 9, 11:10 UTC40m
2026-07-08 GBSYY - Jul 8, 15:15 UTCJul 8, 15:30 UTC15m
2026-07-08 GBSYY - Jul 8, 11:30 UTCJul 8, 13:30 UTC2h 0m
2026-07-08 GBSYY - Jul 8, 08:05 UTCJul 8, 10:45 UTC2h 40m
2026-07-05 GBSYY - Jul 5, 11:00 UTCJul 5, 11:40 UTC40m
2026-07-04 GBSYY - Jul 4, 14:25 UTCJul 4, 15:10 UTC45m
2026-07-04 GBSYY - Jul 4, 11:45 UTCJul 4, 12:20 UTC35m
2026-07-04 GBSYY - Jul 4, 10:15 UTCJul 4, 10:50 UTC35m
2026-06-29 GBSYY - Jun 29, 13:39 UTCJun 29, 14:04 UTC25m
2026-06-29 GBSYY - Jun 29, 12:05 UTCJun 29, 12:24 UTC20m
2026-06-27 GBSYY - Jun 27, 12:15 UTCJun 27, 12:50 UTC35m
2026-06-27 GBSYY - Jun 27, 10:40 UTCJun 27, 11:00 UTC20m
2026-06-26 GBSYY - Jun 26, 14:29 UTCJun 26, 14:59 UTC30m
2026-06-26 GBSYY - Jun 26, 11:55 UTCJun 26, 12:24 UTC30m
2026-06-26 GBSYY - Jun 26, 08:30 UTCJun 26, 09:00 UTC30m
2026-06-25 GBSYY - Jun 25, 13:09 UTCJun 25, 14:39 UTC1h 30m
2026-06-24 GBSYY - Jun 24, 12:34 UTCJun 24, 13:34 UTC1h 0m
2026-06-24 GBSYY - Jun 24, 10:35 UTCJun 24, 11:09 UTC35m
2026-06-24 GBSYY - Jun 24, 08:49 UTCJun 24, 09:59 UTC1h 10m
2026-06-22 GBSYY - Jun 22, 09:34 UTCJun 22, 10:05 UTC30m
2026-06-20 GBSYY - Jun 20, 15:39 UTCJun 20, 16:24 UTC45m
2026-06-20 GBSYY - Jun 20, 13:55 UTCJun 20, 14:09 UTC15m
2026-06-20 GBSYY - Jun 20, 12:24 UTCJun 20, 12:59 UTC35m
2026-06-20 GBSYY - Jun 20, 10:09 UTCJun 20, 10:59 UTC50m
2026-06-19 GBSYY - Jun 19, 11:39 UTCJun 19, 12:19 UTC40m
2026-06-18 GBSYY - Jun 18, 16:05 UTCJun 18, 16:55 UTC50m
2026-06-18 GBSYY - Jun 18, 14:15 UTCJun 18, 14:55 UTC40m
2026-06-18 GBSYY - Jun 18, 11:45 UTCJun 18, 12:05 UTC20m
2026-06-17 GBSYY - Jun 17, 17:55 UTCJun 17, 18:20 UTC25m
2026-06-17 GBSYY - Jun 17, 15:40 UTCJun 17, 16:55 UTC1h 15m
2026-06-17 GBSYY - Jun 17, 14:00 UTCJun 17, 14:40 UTC40m
2026-06-16 GBSYY - Jun 16, 17:49 UTCJun 16, 18:20 UTC30m
2026-06-16 GBSYY - Jun 16, 16:05 UTCJun 16, 17:00 UTC55m
2026-06-16 GBSYY - Jun 16, 14:15 UTCJun 16, 15:20 UTC1h 5m
2026-06-16 GBSYY - Jun 16, 12:20 UTCJun 16, 13:09 UTC50m
2026-06-16 GBSYY - Jun 16, 09:40 UTCJun 16, 10:35 UTC55m
2026-06-13 GBSYY - Jun 13, 14:35 UTCJun 13, 15:10 UTC35m
2026-06-13 GBSYY - Jun 13, 13:10 UTCJun 13, 13:30 UTC20m
2026-06-13 GBSYY - Jun 13, 08:00 UTCJun 13, 08:25 UTC25m
2026-06-12 GBSYY - Jun 12, 12:30 UTCJun 12, 13:25 UTC55m
2026-06-04 GBSYY - Jun 4, 17:30 UTCJun 4, 18:00 UTC30m
2026-06-04 GBSYY - Jun 4, 13:30 UTCJun 4, 14:00 UTC30m
2026-05-31 GBSYY - May 31, 13:45 UTCMay 31, 15:00 UTC1h 15m
2026-05-31 GBSYY - May 31, 11:50 UTCMay 31, 13:05 UTC1h 15m
2026-05-30 GBSYY - May 30, 11:25 UTCMay 30, 12:10 UTC45m

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-BSYY page for operator, model, and routing details .

Mode-S 403321 frequently asked

What is Mode-S code 403321?
403321 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-BSYY.
Where is Mode-S 403321 registered?
Mode-S code 403321 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 403321 broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 403321, octal 20031441, decimal 4,207,393.
What flights does 403321 operate?
Mode-S 403321 has broadcast 1 distinct callsign, including GBSYY.