sensors Mode-S transponder
781F27
ICAO 24-bit transponder address · allocated to China
Currently assigned to B-91A3 · COMAC ARJ-21-700 Xiangfeng
- Hex
- 781F27
- Octal
- 36017447
- Decimal
- 7,872,295
- Country
- CN
- Tail
- B-91A3
- Type
- AJ27
- Flights observed
- 37
- Distinct callsigns
- 15
- Country
- CN
- Last broadcast
- 3d ago
Last known position
Country allocation
The ICAO 24-bit address 781F27 falls within the block assigned to China (CN) by ICAO Annex 10, Volume III. Every aircraft registered in China 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 15 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| CSN5729 | - | 7 | 2026-06-25 |
| CSN5183 | - | 5 | 2026-06-13 |
| CSN5137 | - | 5 | 2026-07-15 |
| CSN5138 | - | 4 | 2026-07-12 |
| CSN3865 | - | 3 | 2026-06-19 |
| CSN5184 | - | 2 | 2026-06-07 |
| CSN8793 | - | 1 | 2026-06-22 |
| CSN8540 | - | 1 | 2026-04-16 |
| CSN6195 | - | 1 | 2026-05-23 |
| CSN5913 | - | 1 | 2026-07-13 |
| CSN5730 | - | 1 | 2026-06-30 |
| CSN3894 | - | 1 | 2026-06-04 |
| CSN3859 | - | 1 | 2026-05-22 |
| CSN3825 | - | 1 | 2026-06-23 |
| CSN2461 | - | 1 | 2026-04-21 |
Recent flights last 37
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-15 | CSN5137 | - | Jul 15, 12:05 UTC | Jul 15, 12:15 UTC | 10m |
| 2026-07-13 | CSN5913 | - | Jul 13, 05:45 UTC | Jul 13, 11:00 UTC | 5h 15m |
| 2026-07-12 | CSN5138 | - | Jul 12, 15:01 UTC | Jul 13, 11:00 UTC | 20h 0m |
| 2026-07-12 | CSN5137 | - | Jul 12, 11:50 UTC | Jul 13, 11:00 UTC | 23h 10m |
| 2026-07-09 | CSN5137 | - | Jul 9, 11:50 UTC | Jul 10, 05:30 UTC | 17h 40m |
| 2026-06-30 | CSN5730 | - | Jun 30, 01:00 UTC | Jun 30, 06:25 UTC | 5h 25m |
| 2026-06-27 | CSN5138 | - | Jun 27, 15:05 UTC | Jun 28, 06:20 UTC | 15h 15m |
| 2026-06-25 | CSN5729 | - | Jun 25, 01:19 UTC | Jun 25, 01:40 UTC | 20m |
| 2026-06-24 | CSN5729 | - | Jun 24, 05:20 UTC | Jun 25, 01:40 UTC | 20h 20m |
| 2026-06-23 | CSN3825 | - | Jun 23, 07:40 UTC | Jun 24, 05:20 UTC | 21h 40m |
| 2026-06-22 | CSN8793 | - | Jun 22, 07:10 UTC | Jun 22, 07:19 UTC | 10m |
| 2026-06-21 | - | - | Jun 21, 09:10 UTC | Jun 21, 09:29 UTC | 20m |
| 2026-06-19 | CSN3865 | - | Jun 19, 00:49 UTC | Jun 19, 06:14 UTC | 5h 25m |
| 2026-06-18 | CSN3865 | - | Jun 18, 10:30 UTC | Jun 19, 06:14 UTC | 19h 44m |
| 2026-06-13 | CSN5183 | - | Jun 13, 07:55 UTC | Jun 13, 12:05 UTC | 4h 10m |
| 2026-06-08 | CSN5183 | - | Jun 8, 07:15 UTC | Jun 8, 07:30 UTC | 15m |
| 2026-06-07 | CSN5184 | - | Jun 7, 12:00 UTC | Jun 7, 12:10 UTC | 10m |
| 2026-06-05 | CSN5729 | - | Jun 5, 01:10 UTC | Jun 5, 12:45 UTC | 11h 35m |
| 2026-06-04 | CSN3894 | - | Jun 4, 02:05 UTC | Jun 4, 02:15 UTC | 10m |
| 2026-06-02 | CSN5184 | - | Jun 2, 12:00 UTC | Jun 2, 12:15 UTC | 15m |
| 2026-06-02 | CSN5183 | - | Jun 2, 07:15 UTC | Jun 2, 07:25 UTC | 10m |
| 2026-05-23 | CSN6195 | - | May 23, 23:40 UTC | May 24, 03:35 UTC | 3h 55m |
| 2026-05-22 | CSN5183 | - | May 22, 07:50 UTC | May 22, 12:15 UTC | 4h 25m |
| 2026-05-22 | CSN3859 | - | May 22, 00:15 UTC | May 22, 05:25 UTC | 5h 10m |
| 2026-05-17 | CSN5729 | - | May 17, 01:00 UTC | May 17, 05:35 UTC | 4h 35m |
| 2026-05-13 | - | - | May 13, 09:25 UTC | May 13, 09:40 UTC | 15m |
| 2026-05-05 | CSN5183 | - | May 5, 07:45 UTC | May 5, 11:55 UTC | 4h 10m |
| 2026-05-05 | CSN5729 | - | May 5, 01:00 UTC | May 5, 05:25 UTC | 4h 25m |
| 2026-05-01 | CSN5138 | URC → SYX | May 1, 15:10 UTC | May 1, 15:20 UTC | 10m |
| 2026-05-01 | CSN5137 | SYX → URC | May 1, 11:50 UTC | May 1, 12:15 UTC | 25m |
| 2026-04-30 | CSN3865 | - | Apr 30, 00:55 UTC | Apr 30, 06:25 UTC | 5h 30m |
| 2026-04-28 | CSN5729 | - | Apr 28, 01:05 UTC | Apr 28, 05:35 UTC | 4h 30m |
| 2026-04-22 | CSN5729 | - | Apr 22, 03:40 UTC | Apr 22, 07:55 UTC | 4h 15m |
| 2026-04-21 | CSN2461 | - | Apr 21, 06:00 UTC | Apr 21, 09:40 UTC | 3h 40m |
| 2026-04-17 | CSN5138 | - | Apr 17, 14:50 UTC | Apr 17, 15:05 UTC | 14m |
| 2026-04-17 | CSN5137 | SYX → URC | Apr 17, 11:45 UTC | Apr 17, 12:05 UTC | 20m |
| 2026-04-16 | CSN8540 | - | Apr 16, 12:29 UTC | Apr 16, 12:45 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 B-91A3 page for operator, model, and routing details .