sensors Mode-S transponder
781DC6
ICAO 24-bit transponder address · allocated to China
Currently assigned to B-221X · BOEING 777-200LR
- Hex
- 781DC6
- Octal
- 36016706
- Decimal
- 7,871,942
- Country
- CN
- Tail
- B-221X
- Type
- B77L
- Flights observed
- 81
- Distinct callsigns
- 7
- Country
- CN
- Last broadcast
- 1d ago
Last known position
Country allocation
The ICAO 24-bit address 781DC6 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 7 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| CYZ257 | - | 36 | 2026-06-01 |
| CYZ258 | - | 13 | 2026-05-31 |
| CYZ294 | - | 9 | 2026-05-13 |
| CYZ237 | - | 8 | 2026-05-12 |
| CYZ278 | - | 5 | 2026-05-09 |
| CYZ256 | China Postal Airlines | 5 | 2026-06-01 |
| CYZ255 | China Postal Airlines | 5 | 2026-05-28 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-01 | CYZ256 | LUX → NKG | Jun 1, 12:55 UTC | Jun 1, 19:10 UTC | 6h 15m |
| 2026-06-01 | CYZ257 | - | Jun 1, 03:15 UTC | Jun 1, 09:35 UTC | 6h 20m |
| 2026-05-31 | CYZ257 | - | May 31, 14:35 UTC | Jun 1, 09:35 UTC | 19h 0m |
| 2026-05-31 | CYZ257 | - | May 31, 09:35 UTC | Jun 1, 09:30 UTC | 23h 55m |
| 2026-05-31 | CYZ258 | - | May 31, 09:00 UTC | Jun 1, 03:50 UTC | 18h 50m |
| 2026-05-30 | CYZ257 | - | May 30, 23:30 UTC | May 30, 23:40 UTC | 10m |
| 2026-05-29 | CYZ258 | - | May 29, 09:55 UTC | May 29, 16:25 UTC | 6h 30m |
| 2026-05-28 | CYZ255 | NKG → LUX | May 28, 23:20 UTC | May 29, 05:30 UTC | 6h 10m |
| 2026-05-27 | CYZ256 | LUX → NKG | May 27, 10:00 UTC | May 27, 16:20 UTC | 6h 20m |
| 2026-05-26 | CYZ255 | NKG → LUX | May 26, 23:14 UTC | May 27, 05:40 UTC | 6h 25m |
| 2026-05-25 | CYZ256 | LUX → NKG | May 25, 13:10 UTC | May 25, 19:10 UTC | 6h 0m |
| 2026-05-24 | CYZ257 | - | May 24, 14:00 UTC | May 25, 09:25 UTC | 19h 25m |
| 2026-05-24 | CYZ257 | - | May 24, 12:05 UTC | May 25, 09:25 UTC | 21h 20m |
| 2026-05-24 | CYZ257 | - | May 24, 09:35 UTC | May 25, 09:25 UTC | 23h 50m |
| 2026-05-24 | CYZ258 | - | May 24, 08:40 UTC | May 25, 07:30 UTC | 22h 50m |
| 2026-05-23 | CYZ257 | - | May 23, 22:50 UTC | May 24, 05:25 UTC | 6h 35m |
| 2026-05-22 | CYZ258 | - | May 22, 10:15 UTC | May 22, 16:15 UTC | 6h 0m |
| 2026-05-22 | CYZ255 | NKG → LUX | May 22, 05:55 UTC | May 22, 06:10 UTC | 15m |
| 2026-05-21 | CYZ255 | NKG → LUX | May 21, 20:30 UTC | May 22, 03:15 UTC | 6h 45m |
| 2026-05-20 | CYZ256 | LUX → NKG | May 20, 09:40 UTC | May 20, 15:40 UTC | 6h 0m |
| 2026-05-19 | CYZ255 | NKG → LUX | May 19, 23:40 UTC | May 20, 06:40 UTC | 7h 1m |
| 2026-05-18 | CYZ256 | LUX → NKG | May 18, 13:25 UTC | May 18, 19:35 UTC | 6h 9m |
| 2026-05-17 | CYZ257 | - | May 17, 14:15 UTC | May 18, 09:10 UTC | 18h 55m |
| 2026-05-17 | CYZ257 | - | May 17, 12:01 UTC | May 18, 09:10 UTC | 21h 10m |
| 2026-05-17 | CYZ257 | - | May 17, 09:35 UTC | May 18, 09:10 UTC | 23h 35m |
| 2026-05-17 | CYZ258 | - | May 17, 08:50 UTC | May 18, 07:30 UTC | 22h 40m |
| 2026-05-16 | CYZ257 | - | May 16, 22:30 UTC | May 17, 05:15 UTC | 6h 45m |
| 2026-05-14 | CYZ258 | - | May 14, 10:15 UTC | May 14, 16:15 UTC | 6h 0m |
| 2026-05-13 | CYZ257 | - | May 13, 11:35 UTC | May 14, 07:00 UTC | 19h 25m |
| 2026-05-13 | CYZ257 | - | May 13, 11:05 UTC | May 14, 07:00 UTC | 19h 55m |
| 2026-05-13 | CYZ257 | - | May 13, 07:35 UTC | May 14, 07:00 UTC | 23h 25m |
| 2026-05-13 | CYZ294 | - | May 13, 05:45 UTC | May 14, 04:00 UTC | 22h 15m |
| 2026-05-12 | CYZ237 | - | May 12, 03:10 UTC | May 12, 09:40 UTC | 6h 30m |
| 2026-05-09 | CYZ278 | - | May 9, 21:50 UTC | May 9, 22:00 UTC | 10m |
| 2026-05-09 | CYZ278 | - | May 9, 11:05 UTC | May 9, 17:10 UTC | 6h 5m |
| 2026-05-08 | CYZ257 | - | May 8, 23:25 UTC | May 9, 07:40 UTC | 8h 15m |
| 2026-05-07 | CYZ258 | - | May 7, 10:55 UTC | May 7, 16:45 UTC | 5h 50m |
| 2026-05-06 | CYZ257 | - | May 6, 23:15 UTC | May 7, 08:00 UTC | 8h 45m |
| 2026-05-06 | CYZ257 | - | May 6, 12:30 UTC | May 7, 08:00 UTC | 19h 30m |
| 2026-05-06 | CYZ257 | - | May 6, 09:35 UTC | May 7, 08:00 UTC | 22h 25m |
| 2026-05-06 | CYZ294 | - | May 6, 07:35 UTC | May 7, 07:30 UTC | 23h 54m |
| 2026-05-06 | CYZ294 | - | May 6, 07:25 UTC | May 7, 04:45 UTC | 21h 19m |
| 2026-05-05 | CYZ237 | - | May 5, 10:05 UTC | May 5, 10:25 UTC | 20m |
| 2026-05-05 | CYZ237 | - | May 5, 01:55 UTC | May 5, 07:10 UTC | 5h 15m |
| 2026-05-02 | CYZ278 | - | May 2, 10:45 UTC | May 2, 16:50 UTC | 6h 5m |
| 2026-05-01 | CYZ257 | - | May 1, 23:15 UTC | May 2, 07:10 UTC | 7h 55m |
| 2026-04-30 | CYZ258 | - | Apr 30, 10:55 UTC | Apr 30, 17:10 UTC | 6h 15m |
| 2026-04-29 | CYZ257 | - | Apr 29, 11:35 UTC | Apr 30, 07:00 UTC | 19h 24m |
| 2026-04-29 | CYZ257 | - | Apr 29, 09:35 UTC | Apr 30, 07:00 UTC | 21h 24m |
| 2026-04-29 | CYZ257 | - | Apr 29, 07:35 UTC | Apr 30, 07:00 UTC | 23h 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 B-221X page for operator, model, and routing details .