sensors Mode-S transponder
406631
ICAO 24-bit transponder address · allocated to United Kingdom
- Hex
- 406631
- Octal
- 20063061
- Decimal
- 4,220,465
- Country
- GB
- Flights observed
- 16
- Distinct callsigns
- 9
- Country
- GB
- Last broadcast
- 3d ago
Last known position
Country allocation
The ICAO 24-bit address 406631 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 9 distinct
Recent flights last 16
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | EXS2KF | - | Jul 13, 22:35 UTC | Jul 14, 16:25 UTC | 17h 50m |
| 2026-07-12 | EXS2KC | - | Jul 12, 07:01 UTC | Jul 12, 16:40 UTC | 9h 40m |
| 2026-07-11 | EXS6MT | - | Jul 11, 12:30 UTC | Jul 12, 07:05 UTC | 18h 35m |
| 2026-07-11 | EXS6MT | - | Jul 11, 06:05 UTC | Jul 11, 12:30 UTC | 6h 25m |
| 2026-07-09 | EXS62FG | - | Jul 9, 15:00 UTC | Jul 9, 15:15 UTC | 15m |
| 2026-07-06 | - | - | Jul 6, 17:40 UTC | Jul 6, 17:50 UTC | 10m |
| 2026-06-30 | EXS82P | - | Jun 30, 08:00 UTC | Jun 30, 13:10 UTC | 5h 10m |
| 2026-06-25 | - | - | Jun 25, 20:14 UTC | Jun 25, 20:25 UTC | 10m |
| 2026-06-24 | - | - | Jun 24, 20:40 UTC | Jun 25, 20:14 UTC | 23h 35m |
| 2026-06-17 | - | - | Jun 17, 13:40 UTC | Jun 17, 13:50 UTC | 10m |
| 2026-06-16 | - | - | Jun 16, 17:30 UTC | Jun 17, 13:50 UTC | 20h 21m |
| 2026-06-05 | EXS28WR | SZG → BHX | Jun 5, 18:10 UTC | Jun 6, 05:40 UTC | 11h 30m |
| 2026-06-05 | - | - | Jun 5, 06:35 UTC | Jun 5, 15:55 UTC | 9h 20m |
| 2026-06-03 | EXS9BY | KEF → EMA | Jun 3, 16:00 UTC | Jun 4, 07:55 UTC | 15h 55m |
| 2026-05-29 | EXS36JU | - | May 29, 16:00 UTC | May 29, 21:20 UTC | 5h 20m |
| 2026-05-01 | EXS12DR | BHX → KGS | May 1, 18:50 UTC | May 2, 00:05 UTC | 5h 15m |
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.