sensors Mode-S transponder
A0C903
ICAO 24-bit transponder address · allocated to United States
- Hex
- A0C903
- Octal
- 50144403
- Decimal
- 10,537,219
- Country
- US
- Flights observed
- 39
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- 27d ago
Last known position
Country allocation
The ICAO 24-bit address A0C903 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 |
|---|---|---|---|
| N15NA | - | 39 | 2026-07-24 |
Recent flights last 39
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-24 | N15NA | - | Jul 24, 21:20 UTC | Jul 24, 23:10 UTC | 1h 50m |
| 2026-07-09 | N15NA | - | Jul 9, 19:15 UTC | Jul 9, 20:10 UTC | 55m |
| 2026-07-06 | N15NA | - | Jul 6, 00:10 UTC | Jul 6, 00:45 UTC | 35m |
| 2026-07-05 | N15NA | - | Jul 5, 21:55 UTC | Jul 5, 22:30 UTC | 35m |
| 2026-06-28 | N15NA | - | Jun 28, 17:50 UTC | Jun 28, 18:44 UTC | 55m |
| 2026-06-24 | N15NA | - | Jun 24, 20:14 UTC | Jun 24, 20:40 UTC | 25m |
| 2026-06-24 | N15NA | - | Jun 24, 14:55 UTC | Jun 24, 16:05 UTC | 1h 10m |
| 2026-06-24 | N15NA | - | Jun 24, 13:20 UTC | Jun 24, 14:15 UTC | 55m |
| 2026-06-22 | N15NA | - | Jun 22, 21:40 UTC | Jun 22, 22:30 UTC | 50m |
| 2026-06-22 | N15NA | - | Jun 22, 13:54 UTC | Jun 22, 14:49 UTC | 55m |
| 2026-06-20 | N15NA | - | Jun 20, 19:19 UTC | Jun 20, 20:20 UTC | 1h 0m |
| 2026-06-20 | N15NA | - | Jun 20, 17:34 UTC | Jun 20, 18:34 UTC | 1h 0m |
| 2026-06-05 | N15NA | - | Jun 5, 22:15 UTC | Jun 5, 22:45 UTC | 30m |
| 2026-06-05 | N15NA | - | Jun 5, 20:30 UTC | Jun 5, 20:55 UTC | 25m |
| 2026-06-02 | N15NA | - | Jun 2, 21:50 UTC | Jun 2, 22:15 UTC | 25m |
| 2026-06-02 | N15NA | - | Jun 2, 20:20 UTC | Jun 2, 20:45 UTC | 25m |
| 2026-05-31 | N15NA | - | May 31, 20:55 UTC | May 31, 21:45 UTC | 50m |
| 2026-05-26 | N15NA | - | May 26, 22:29 UTC | May 26, 23:05 UTC | 35m |
| 2026-05-26 | N15NA | - | May 26, 19:40 UTC | May 26, 20:15 UTC | 35m |
| 2026-05-25 | N15NA | - | May 25, 19:54 UTC | May 25, 21:40 UTC | 1h 45m |
| 2026-05-22 | N15NA | - | May 22, 13:20 UTC | May 22, 15:05 UTC | 1h 45m |
| 2026-05-18 | N15NA | - | May 18, 23:25 UTC | May 19, 00:25 UTC | 1h 0m |
| 2026-05-15 | N15NA | - | May 15, 23:20 UTC | May 16, 00:10 UTC | 50m |
| 2026-05-10 | N15NA | - | May 10, 21:35 UTC | May 10, 22:55 UTC | 1h 20m |
| 2026-05-06 | N15NA | - | May 6, 22:45 UTC | May 6, 23:30 UTC | 45m |
| 2026-05-06 | N15NA | - | May 6, 15:35 UTC | May 6, 16:35 UTC | 1h 0m |
| 2026-05-02 | N15NA | - | May 2, 20:30 UTC | May 2, 21:20 UTC | 50m |
| 2026-05-01 | N15NA | - | May 1, 16:45 UTC | May 1, 17:45 UTC | 1h 0m |
| 2026-04-28 | N15NA | - | Apr 28, 23:14 UTC | Apr 29, 00:05 UTC | 50m |
| 2026-04-27 | N15NA | - | Apr 27, 20:10 UTC | Apr 27, 21:55 UTC | 1h 45m |
| 2026-04-26 | N15NA | - | Apr 26, 14:10 UTC | Apr 26, 16:00 UTC | 1h 50m |
| 2026-04-26 | N15NA | - | Apr 26, 05:20 UTC | Apr 26, 05:45 UTC | 25m |
| 2026-04-25 | N15NA | - | Apr 25, 20:45 UTC | Apr 25, 21:05 UTC | 20m |
| 2026-04-19 | N15NA | - | Apr 19, 20:10 UTC | Apr 19, 21:45 UTC | 1h 35m |
| 2026-04-19 | N15NA | - | Apr 19, 15:55 UTC | Apr 19, 19:15 UTC | 3h 20m |
| 2026-04-16 | N15NA | - | Apr 16, 18:20 UTC | Apr 16, 19:00 UTC | 40m |
| 2026-04-15 | N15NA | - | Apr 15, 15:05 UTC | Apr 15, 16:25 UTC | 1h 20m |
| 2026-04-15 | N15NA | - | Apr 15, 13:01 UTC | Apr 15, 14:55 UTC | 1h 54m |
| 2026-04-13 | N15NA | FWH → MDD | Apr 13, 13:35 UTC | Apr 13, 14:35 UTC | 1h 0m |
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.