sensors Mode-S transponder
424B31
ICAO 24-bit transponder address · allocated to United Kingdom
Currently assigned to M-ARDI · GULFSTREAM G650
- Hex
- 424B31
- Octal
- 20445461
- Decimal
- 4,344,625
- Country
- GB
- Tail
- M-ARDI
- Type
- GLF6
- Flights observed
- 35
- Distinct callsigns
- 2
- Country
- GB
- Last broadcast
- 1d ago
Last known position
Country allocation
The ICAO 24-bit address 424B31 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 2 distinct
Recent flights last 35
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-31 | MARDI | - | May 31, 23:45 UTC | Jun 1, 05:40 UTC | 5h 55m |
| 2026-05-27 | MARDI | - | May 27, 00:04 UTC | May 27, 00:49 UTC | 45m |
| 2026-05-26 | MARDI | - | May 26, 15:20 UTC | May 26, 16:00 UTC | 40m |
| 2026-05-23 | MARDI | - | May 23, 03:10 UTC | May 23, 04:10 UTC | 1h 0m |
| 2026-05-21 | MARDI | - | May 21, 20:00 UTC | May 21, 23:15 UTC | 3h 15m |
| 2026-05-19 | MARDI | - | May 19, 20:15 UTC | May 20, 06:20 UTC | 10h 6m |
| 2026-05-19 | MARDI | - | May 19, 04:00 UTC | May 19, 05:50 UTC | 1h 50m |
| 2026-05-18 | MARDI | - | May 18, 16:45 UTC | May 18, 18:25 UTC | 1h 40m |
| 2026-05-18 | MARDI | - | May 18, 04:00 UTC | May 18, 05:55 UTC | 1h 55m |
| 2026-05-17 | MARDI | - | May 17, 03:55 UTC | May 17, 05:30 UTC | 1h 35m |
| 2026-05-15 | MARDI | - | May 15, 13:20 UTC | May 15, 15:40 UTC | 2h 19m |
| 2026-05-14 | MARDI1 | - | May 14, 18:00 UTC | May 15, 00:40 UTC | 6h 40m |
| 2026-05-13 | MARDI | - | May 13, 17:50 UTC | May 13, 23:05 UTC | 5h 15m |
| 2026-05-12 | MARDI | - | May 12, 22:20 UTC | May 13, 22:15 UTC | 23h 55m |
| 2026-05-12 | MARDI | - | May 12, 20:20 UTC | May 13, 19:40 UTC | 23h 20m |
| 2026-05-12 | MARDI | - | May 12, 18:20 UTC | May 13, 18:15 UTC | 23h 55m |
| 2026-05-12 | MARDI | - | May 12, 18:05 UTC | May 12, 22:45 UTC | 4h 40m |
| 2026-05-10 | MARDI | - | May 10, 23:39 UTC | May 11, 05:35 UTC | 5h 55m |
| 2026-05-08 | MARDI | BQH → HPN | May 8, 16:05 UTC | May 8, 22:45 UTC | 6h 40m |
| 2026-05-04 | MARDI | - | May 4, 23:40 UTC | May 5, 05:45 UTC | 6h 5m |
| 2026-05-04 | MARDI | - | May 4, 19:30 UTC | May 4, 20:25 UTC | 55m |
| 2026-05-02 | MARDI | - | May 2, 13:30 UTC | May 2, 14:40 UTC | 1h 10m |
| 2026-05-01 | MARDI | - | May 1, 14:05 UTC | May 1, 17:05 UTC | 3h 0m |
| 2026-04-30 | MARDI | BQH → HPN | Apr 30, 18:00 UTC | May 1, 00:30 UTC | 6h 30m |
| 2026-04-28 | MARDI | - | Apr 28, 00:20 UTC | Apr 28, 07:05 UTC | 6h 45m |
| 2026-04-27 | MARDI | - | Apr 27, 20:00 UTC | Apr 27, 20:35 UTC | 35m |
| 2026-04-24 | MARDI | - | Apr 24, 17:00 UTC | Apr 24, 23:00 UTC | 6h 0m |
| 2026-04-20 | MARDI | - | Apr 20, 00:15 UTC | Apr 20, 06:15 UTC | 6h 0m |
| 2026-04-19 | MARDI | - | Apr 19, 19:30 UTC | Apr 19, 20:15 UTC | 45m |
| 2026-04-16 | MARDI | - | Apr 16, 15:15 UTC | Apr 16, 15:40 UTC | 25m |
| 2026-04-16 | MARDI | - | Apr 16, 15:05 UTC | Apr 16, 15:10 UTC | 5m |
| 2026-04-16 | MARDI | - | Apr 16, 01:10 UTC | Apr 16, 02:50 UTC | 1h 40m |
| 2026-04-16 | MARDI | - | Apr 16, 00:35 UTC | Apr 16, 01:05 UTC | 30m |
| 2026-04-15 | MARDI | - | Apr 15, 22:05 UTC | Apr 15, 22:20 UTC | 15m |
| 2026-04-13 | MARDI | - | Apr 13, 23:25 UTC | Apr 13, 23:40 UTC | 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.
Prefer a tail-number view? See the M-ARDI page for operator, model, and routing details .