sensors Mode-S transponder
A17D4F
ICAO 24-bit transponder address · allocated to United States
Currently assigned to N1951X · CESSNA 182 Skylane · operated by SKYLINE AIRCRAFT MAINTENANCE INC
- Hex
- A17D4F
- Octal
- 50276517
- Decimal
- 10,583,375
- Country
- US
- Tail
- N1951X
- Type
- C182
- Flights observed
- 52
- Distinct callsigns
- 1
- Country
- US
- Last broadcast
- Jul 22, 13:55 UTC
Last known position
Country allocation
The ICAO 24-bit address A17D4F 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 |
|---|---|---|---|
| N1951X | - | 52 | 2026-07-22 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-22 | N1951X | - | Jul 22, 13:45 UTC | Jul 22, 13:55 UTC | 10m |
| 2026-07-21 | N1951X | - | Jul 21, 23:35 UTC | Jul 21, 23:45 UTC | 10m |
| 2026-07-21 | N1951X | - | Jul 21, 13:10 UTC | Jul 21, 13:20 UTC | 10m |
| 2026-07-08 | N1951X | - | Jul 8, 23:30 UTC | Jul 8, 23:40 UTC | 10m |
| 2026-07-08 | N1951X | - | Jul 8, 13:55 UTC | Jul 8, 14:05 UTC | 10m |
| 2026-07-08 | N1951X | - | Jul 8, 00:15 UTC | Jul 8, 00:25 UTC | 10m |
| 2026-07-07 | N1951X | - | Jul 7, 19:50 UTC | Jul 7, 20:00 UTC | 10m |
| 2026-07-03 | N1951X | - | Jul 3, 18:00 UTC | Jul 3, 18:20 UTC | 20m |
| 2026-06-30 | N1951X | - | Jun 30, 22:45 UTC | Jun 30, 22:55 UTC | 10m |
| 2026-06-26 | N1951X | - | Jun 26, 13:49 UTC | Jun 26, 14:09 UTC | 20m |
| 2026-06-25 | N1951X | - | Jun 25, 22:59 UTC | Jun 25, 23:09 UTC | 10m |
| 2026-06-23 | N1951X | - | Jun 23, 13:19 UTC | Jun 23, 13:29 UTC | 10m |
| 2026-06-22 | N1951X | - | Jun 22, 22:19 UTC | Jun 22, 23:29 UTC | 1h 10m |
| 2026-06-12 | N1951X | - | Jun 12, 13:35 UTC | Jun 12, 13:45 UTC | 10m |
| 2026-06-11 | N1951X | - | Jun 11, 13:30 UTC | Jun 11, 13:40 UTC | 10m |
| 2026-06-10 | N1951X | - | Jun 10, 22:35 UTC | Jun 10, 22:45 UTC | 10m |
| 2026-06-10 | N1951X | - | Jun 10, 14:20 UTC | Jun 10, 14:30 UTC | 10m |
| 2026-06-09 | N1951X | - | Jun 9, 13:15 UTC | Jun 9, 13:25 UTC | 10m |
| 2026-06-05 | N1951X | - | Jun 5, 14:40 UTC | Jun 5, 14:50 UTC | 10m |
| 2026-06-04 | N1951X | - | Jun 4, 23:00 UTC | Jun 4, 23:10 UTC | 10m |
| 2026-06-02 | N1951X | - | Jun 2, 23:10 UTC | Jun 2, 23:20 UTC | 10m |
| 2026-06-02 | N1951X | - | Jun 2, 01:50 UTC | Jun 2, 02:00 UTC | 10m |
| 2026-05-29 | N1951X | - | May 29, 20:50 UTC | May 29, 21:00 UTC | 10m |
| 2026-05-26 | N1951X | - | May 26, 22:54 UTC | May 26, 23:39 UTC | 45m |
| 2026-05-26 | N1951X | - | May 26, 12:54 UTC | May 26, 13:04 UTC | 10m |
| 2026-05-22 | N1951X | - | May 22, 17:25 UTC | May 22, 17:35 UTC | 10m |
| 2026-05-22 | N1951X | - | May 22, 12:45 UTC | May 22, 12:55 UTC | 10m |
| 2026-05-21 | N1951X | - | May 21, 18:40 UTC | May 21, 18:55 UTC | 15m |
| 2026-05-21 | N1951X | - | May 21, 14:05 UTC | May 21, 14:15 UTC | 10m |
| 2026-05-19 | N1951X | - | May 19, 23:15 UTC | May 19, 23:25 UTC | 10m |
| 2026-05-19 | N1951X | - | May 19, 13:40 UTC | May 19, 13:55 UTC | 15m |
| 2026-05-19 | N1951X | - | May 19, 12:20 UTC | May 19, 12:45 UTC | 25m |
| 2026-05-18 | N1951X | - | May 18, 13:00 UTC | May 18, 13:10 UTC | 10m |
| 2026-05-17 | N1951X | - | May 17, 20:20 UTC | May 17, 20:30 UTC | 10m |
| 2026-05-16 | N1951X | - | May 16, 22:30 UTC | May 16, 22:40 UTC | 10m |
| 2026-05-11 | N1951X | - | May 11, 13:30 UTC | May 11, 13:40 UTC | 10m |
| 2026-05-09 | N1951X | - | May 9, 18:35 UTC | May 9, 18:45 UTC | 10m |
| 2026-05-07 | N1951X | - | May 7, 23:09 UTC | May 7, 23:19 UTC | 10m |
| 2026-05-07 | N1951X | - | May 7, 12:55 UTC | May 7, 13:05 UTC | 10m |
| 2026-05-07 | N1951X | - | May 7, 01:55 UTC | May 7, 02:05 UTC | 10m |
| 2026-05-06 | N1951X | - | May 6, 13:05 UTC | May 6, 13:15 UTC | 10m |
| 2026-05-06 | N1951X | - | May 6, 00:31 UTC | May 6, 00:50 UTC | 20m |
| 2026-05-05 | N1951X | - | May 5, 23:35 UTC | May 5, 23:45 UTC | 10m |
| 2026-05-02 | N1951X | - | May 2, 15:25 UTC | May 2, 15:35 UTC | 10m |
| 2026-05-01 | N1951X | - | May 1, 13:35 UTC | May 1, 13:45 UTC | 10m |
| 2026-05-01 | N1951X | - | May 1, 00:50 UTC | May 1, 01:10 UTC | 20m |
| 2026-04-30 | N1951X | - | Apr 30, 01:05 UTC | Apr 30, 01:15 UTC | 10m |
| 2026-04-27 | N1951X | - | Apr 27, 13:20 UTC | Apr 27, 13:30 UTC | 10m |
| 2026-04-25 | N1951X | - | Apr 25, 12:50 UTC | Apr 25, 13:00 UTC | 10m |
| 2026-04-24 | N1951X | - | Apr 24, 22:45 UTC | Apr 24, 22:55 UTC | 10m |
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 N1951X page for operator, model, and routing details .