sensors Mode-S transponder
AB6D7B
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N8351U · operated by RAPPA COLIN C
- Hex
- AB6D7B
- Octal
- 52666573
- Decimal
- 11,234,683
- Country
- US
- Tail
- N8351U
- Type
- C172
- Flights observed
- 39
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- Jul 25, 15:20 UTC
Last known position
Country allocation
The ICAO 24-bit address AB6D7B 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 |
|---|---|---|---|
| N8351U | - | 39 | 2026-07-25 |
Recent flights last 39
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-25 | N8351U | - | Jul 25, 15:00 UTC | Jul 25, 15:20 UTC | 20m |
| 2026-07-24 | N8351U | - | Jul 24, 19:55 UTC | Jul 24, 20:15 UTC | 20m |
| 2026-07-24 | N8351U | - | Jul 24, 00:15 UTC | Jul 24, 00:50 UTC | 35m |
| 2026-07-20 | N8351U | - | Jul 20, 23:15 UTC | Jul 20, 23:50 UTC | 35m |
| 2026-07-19 | N8351U | - | Jul 19, 22:30 UTC | Jul 19, 23:25 UTC | 55m |
| 2026-07-09 | N8351U | - | Jul 9, 01:05 UTC | Jul 9, 01:20 UTC | 15m |
| 2026-07-08 | N8351U | - | Jul 8, 15:30 UTC | Jul 8, 15:45 UTC | 15m |
| 2026-06-29 | N8351U | - | Jun 29, 23:49 UTC | Jun 30, 01:09 UTC | 1h 20m |
| 2026-06-25 | N8351U | - | Jun 25, 00:44 UTC | Jun 25, 01:19 UTC | 35m |
| 2026-06-23 | N8351U | - | Jun 23, 23:29 UTC | Jun 24, 00:44 UTC | 1h 15m |
| 2026-06-21 | N8351U | - | Jun 21, 23:05 UTC | Jun 21, 23:30 UTC | 25m |
| 2026-06-16 | N8351U | - | Jun 16, 16:39 UTC | Jun 16, 17:00 UTC | 20m |
| 2026-06-13 | N8351U | - | Jun 13, 22:30 UTC | Jun 13, 23:00 UTC | 30m |
| 2026-06-13 | N8351U | - | Jun 13, 15:35 UTC | Jun 13, 15:45 UTC | 10m |
| 2026-06-13 | N8351U | - | Jun 13, 01:10 UTC | Jun 13, 01:25 UTC | 15m |
| 2026-06-04 | N8351U | - | Jun 4, 23:25 UTC | Jun 4, 23:45 UTC | 20m |
| 2026-05-29 | N8351U | - | May 29, 16:35 UTC | May 29, 19:55 UTC | 3h 20m |
| 2026-05-29 | N8351U | - | May 29, 12:50 UTC | May 29, 15:25 UTC | 2h 35m |
| 2026-05-26 | N8351U | - | May 26, 15:49 UTC | May 26, 16:05 UTC | 15m |
| 2026-05-25 | N8351U | - | May 25, 21:35 UTC | May 25, 21:54 UTC | 20m |
| 2026-05-25 | N8351U | - | May 25, 18:55 UTC | May 25, 19:15 UTC | 20m |
| 2026-05-21 | N8351U | - | May 21, 23:05 UTC | May 21, 23:45 UTC | 40m |
| 2026-05-18 | N8351U | - | May 18, 00:05 UTC | May 18, 00:35 UTC | 30m |
| 2026-05-17 | N8351U | - | May 17, 00:20 UTC | May 17, 00:35 UTC | 15m |
| 2026-05-16 | N8351U | - | May 16, 01:45 UTC | May 16, 02:00 UTC | 15m |
| 2026-05-11 | N8351U | - | May 11, 20:55 UTC | May 11, 21:15 UTC | 20m |
| 2026-05-11 | N8351U | - | May 11, 15:15 UTC | May 11, 15:35 UTC | 20m |
| 2026-05-07 | N8351U | - | May 7, 22:05 UTC | May 7, 22:35 UTC | 30m |
| 2026-05-07 | N8351U | - | May 7, 20:20 UTC | May 7, 20:40 UTC | 20m |
| 2026-05-01 | N8351U | - | May 1, 18:05 UTC | May 1, 18:25 UTC | 20m |
| 2026-05-01 | N8351U | - | May 1, 16:30 UTC | May 1, 16:50 UTC | 20m |
| 2026-04-28 | N8351U | - | Apr 28, 23:00 UTC | Apr 28, 23:29 UTC | 30m |
| 2026-04-27 | N8351U | - | Apr 27, 19:25 UTC | Apr 27, 19:35 UTC | 10m |
| 2026-04-26 | N8351U | - | Apr 26, 20:45 UTC | Apr 26, 21:25 UTC | 40m |
| 2026-04-18 | N8351U | - | Apr 18, 16:45 UTC | Apr 18, 17:10 UTC | 25m |
| 2026-04-17 | N8351U | - | Apr 17, 18:00 UTC | Apr 17, 18:15 UTC | 15m |
| 2026-04-17 | N8351U | - | Apr 17, 12:40 UTC | Apr 17, 12:55 UTC | 15m |
| 2026-04-12 | N8351U | - | Apr 12, 19:05 UTC | Apr 12, 20:00 UTC | 55m |
| 2026-04-12 | N8351U | - | Apr 12, 17:15 UTC | Apr 12, 17:40 UTC | 25m |
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 N8351U page for operator, model, and routing details .