sensors Mode-S transponder
A500D6
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N421RJ · CESSNA 421 Executive Commuter · operated by GREAT TRENDS LLC
- Hex
- A500D6
- Octal
- 51200326
- Decimal
- 10,813,654
- Country
- US
- Tail
- N421RJ
- Type
- C421
- Flights observed
- 28
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- 13d ago
Last known position
Country allocation
The ICAO 24-bit address A500D6 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States 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 |
|---|---|---|---|
| N421RJ | - | 28 | 2026-07-19 |
Recent flights last 28
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-19 | N421RJ | - | Jul 19, 18:25 UTC | Jul 19, 20:05 UTC | 1h 40m |
| 2026-07-12 | N421RJ | BJC → MSC | Jul 12, 14:50 UTC | Jul 12, 17:20 UTC | 2h 30m |
| 2026-07-10 | N421RJ | - | Jul 10, 15:55 UTC | Jul 10, 18:35 UTC | 2h 40m |
| 2026-07-08 | N421RJ | - | Jul 8, 13:10 UTC | Jul 8, 15:50 UTC | 2h 40m |
| 2026-07-07 | N421RJ | - | Jul 7, 15:30 UTC | Jul 7, 16:45 UTC | 1h 15m |
| 2026-07-07 | N421RJ | - | Jul 7, 14:15 UTC | Jul 7, 14:55 UTC | 40m |
| 2026-07-06 | N421RJ | - | Jul 6, 03:25 UTC | Jul 6, 05:00 UTC | 1h 35m |
| 2026-06-29 | N421RJ | - | Jun 29, 18:49 UTC | Jun 29, 20:40 UTC | 1h 50m |
| 2026-06-28 | N421RJ | - | Jun 28, 04:35 UTC | Jun 28, 06:05 UTC | 1h 30m |
| 2026-06-27 | N421RJ | - | Jun 27, 15:34 UTC | Jun 27, 17:25 UTC | 1h 50m |
| 2026-06-22 | N421RJ | - | Jun 22, 03:19 UTC | Jun 22, 04:49 UTC | 1h 30m |
| 2026-06-21 | N421RJ | - | Jun 21, 00:45 UTC | Jun 21, 02:45 UTC | 2h 0m |
| 2026-06-20 | N421RJ | - | Jun 20, 23:45 UTC | Jun 21, 00:04 UTC | 20m |
| 2026-06-19 | N421RJ | - | Jun 19, 19:14 UTC | Jun 19, 19:34 UTC | 20m |
| 2026-06-19 | N421RJ | - | Jun 19, 17:34 UTC | Jun 19, 18:09 UTC | 35m |
| 2026-06-16 | N421RJ | - | Jun 16, 02:04 UTC | Jun 16, 03:50 UTC | 1h 45m |
| 2026-06-15 | N421RJ | - | Jun 15, 02:30 UTC | Jun 15, 04:15 UTC | 1h 45m |
| 2026-06-08 | N421RJ | - | Jun 8, 00:40 UTC | Jun 8, 02:20 UTC | 1h 40m |
| 2026-06-06 | N421RJ | - | Jun 6, 19:04 UTC | Jun 6, 21:00 UTC | 1h 55m |
| 2026-06-06 | N421RJ | - | Jun 6, 14:09 UTC | Jun 6, 15:54 UTC | 1h 45m |
| 2026-06-03 | N421RJ | - | Jun 3, 19:40 UTC | Jun 3, 21:20 UTC | 1h 40m |
| 2026-05-30 | N421RJ | - | May 30, 17:40 UTC | May 30, 19:20 UTC | 1h 40m |
| 2026-05-28 | N421RJ | - | May 28, 01:15 UTC | May 28, 03:10 UTC | 1h 55m |
| 2026-05-02 | N421RJ | - | May 2, 05:15 UTC | May 2, 06:00 UTC | 45m |
| 2026-05-02 | N421RJ | - | May 2, 04:00 UTC | May 2, 04:25 UTC | 25m |
| 2026-05-01 | N421RJ | - | May 1, 21:40 UTC | May 1, 22:10 UTC | 30m |
| 2026-05-01 | N421RJ | - | May 1, 19:55 UTC | May 1, 20:40 UTC | 45m |
| 2026-04-18 | N421RJ | - | Apr 18, 15:45 UTC | Apr 18, 16:15 UTC | 30m |
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 N421RJ page for operator, model, and routing details .