sensors Mode-S transponder
781D8D
ICAO 24-bit transponder address · allocated to China
Currently assigned to B-221W · BOEING 777-200LR
- Hex
- 781D8D
- Octal
- 36016615
- Decimal
- 7,871,885
- Country
- CN
- Tail
- B-221W
- Type
- B77L
- Flights observed
- 128
- Distinct callsigns
- 20
- Country
- CN
- Last broadcast
- 1h ago
Last known position
Country allocation
The ICAO 24-bit address 781D8D 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 20 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| CKK223 | China Cargo Airlines | 20 | 2026-05-24 |
| CKK227 | China Cargo Airlines | 19 | 2026-05-28 |
| CKK224 | China Cargo Airlines | 18 | 2026-05-25 |
| CKK225 | China Cargo Airlines | 12 | 2026-05-13 |
| CKK228 | China Cargo Airlines | 11 | 2026-05-28 |
| CKK231 | China Cargo Airlines | 8 | 2026-05-02 |
| CKK221 | China Cargo Airlines | 8 | 2026-05-15 |
| CKK226 | China Cargo Airlines | 6 | 2026-05-13 |
| CKK222 | China Cargo Airlines | 6 | 2026-05-16 |
| CKK206 | China Cargo Airlines | 4 | 2026-04-20 |
| CKK287 | China Cargo Airlines | 3 | 2026-05-29 |
| CKK232 | China Cargo Airlines | 2 | 2026-05-02 |
| CKK210 | China Cargo Airlines | 2 | 2026-05-10 |
| CKK205 | China Cargo Airlines | 2 | 2026-04-19 |
| CKK288 | - | 1 | 2026-05-20 |
| CKK264 | China Cargo Airlines | 1 | 2026-05-16 |
| CKK263 | China Cargo Airlines | 1 | 2026-05-16 |
| CKK261 | China Cargo Airlines | 1 | 2026-04-27 |
| CKK258 | China Cargo Airlines | 1 | 2026-05-19 |
| CKK241 | China Cargo Airlines | 1 | 2026-05-14 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-05-29 | CKK287 | PVG → SIN | May 29, 18:20 UTC | May 30, 04:35 UTC | 10h 15m |
| 2026-05-28 | CKK228 | ORD → PVG | May 28, 21:20 UTC | May 29, 16:45 UTC | 19h 25m |
| 2026-05-28 | CKK228 | ORD → PVG | May 28, 20:55 UTC | May 29, 16:45 UTC | 19h 50m |
| 2026-05-28 | CKK227 | PVG → ANC | May 28, 12:30 UTC | May 28, 17:55 UTC | 5h 25m |
| 2026-05-28 | CKK227 | PVG → ANC | May 28, 04:00 UTC | May 28, 11:05 UTC | 7h 5m |
| 2026-05-27 | CKK227 | PVG → ANC | May 27, 12:00 UTC | May 28, 11:05 UTC | 23h 5m |
| 2026-05-26 | CKK228 | ORD → PVG | May 26, 23:54 UTC | May 27, 12:45 UTC | 12h 50m |
| 2026-05-26 | CKK227 | PVG → ANC | May 26, 15:29 UTC | May 26, 20:54 UTC | 5h 25m |
| 2026-05-25 | CKK227 | PVG → ANC | May 25, 21:49 UTC | May 26, 13:54 UTC | 16h 5m |
| 2026-05-25 | CKK227 | PVG → ANC | May 25, 17:20 UTC | May 26, 13:54 UTC | 20h 34m |
| 2026-05-25 | CKK227 | PVG → ANC | May 25, 15:30 UTC | May 26, 13:54 UTC | 22h 24m |
| 2026-05-25 | CKK224 | LAX → PVG | May 25, 14:15 UTC | May 26, 13:15 UTC | 22h 59m |
| 2026-05-25 | CKK224 | LAX → PVG | May 25, 11:20 UTC | May 26, 07:49 UTC | 20h 29m |
| 2026-05-25 | CKK224 | LAX → PVG | May 25, 11:10 UTC | May 26, 07:49 UTC | 20h 39m |
| 2026-05-24 | CKK223 | PVG → LAX | May 24, 20:30 UTC | May 25, 07:05 UTC | 10h 35m |
| 2026-05-24 | CKK223 | PVG → LAX | May 24, 09:40 UTC | May 25, 07:05 UTC | 21h 25m |
| 2026-05-24 | CKK223 | PVG → LAX | May 24, 03:35 UTC | May 24, 21:50 UTC | 18h 15m |
| 2026-05-23 | CKK223 | PVG → LAX | May 23, 23:20 UTC | May 24, 21:50 UTC | 22h 30m |
| 2026-05-23 | CKK228 | ORD → PVG | May 23, 21:50 UTC | May 24, 21:15 UTC | 23h 25m |
| 2026-05-23 | CKK227 | PVG → ANC | May 23, 12:55 UTC | May 23, 18:20 UTC | 5h 26m |
| 2026-05-22 | CKK227 | PVG → ANC | May 22, 19:45 UTC | May 23, 11:25 UTC | 15h 39m |
| 2026-05-22 | CKK224 | LAX → PVG | May 22, 09:20 UTC | May 23, 05:35 UTC | 20h 14m |
| 2026-05-22 | CKK224 | LAX → PVG | May 22, 09:00 UTC | May 23, 05:35 UTC | 20h 34m |
| 2026-05-21 | CKK223 | PVG → LAX | May 21, 20:30 UTC | May 22, 06:35 UTC | 10h 5m |
| 2026-05-21 | CKK223 | PVG → LAX | May 21, 07:20 UTC | May 22, 06:35 UTC | 23h 15m |
| 2026-05-21 | CKK223 | PVG → LAX | May 21, 07:05 UTC | May 22, 05:15 UTC | 22h 10m |
| 2026-05-20 | CKK288 | - | May 20, 07:35 UTC | May 21, 02:10 UTC | 18h 35m |
| 2026-05-20 | CKK287 | PVG → SIN | May 20, 05:25 UTC | May 20, 05:50 UTC | 25m |
| 2026-05-19 | CKK258 | ICN → PVG | May 19, 20:15 UTC | May 20, 02:55 UTC | 6h 40m |
| 2026-05-18 | CKK228 | ORD → PVG | May 18, 23:20 UTC | May 19, 17:35 UTC | 18h 15m |
| 2026-05-18 | CKK228 | ORD → PVG | May 18, 22:20 UTC | May 19, 17:35 UTC | 19h 15m |
| 2026-05-18 | CKK227 | PVG → ANC | May 18, 12:50 UTC | May 18, 18:20 UTC | 5h 30m |
| 2026-05-18 | CKK227 | PVG → ANC | May 18, 03:45 UTC | May 18, 11:25 UTC | 7h 40m |
| 2026-05-16 | CKK264 | HKG → PVG | May 16, 23:05 UTC | May 16, 23:20 UTC | 15m |
| 2026-05-16 | CKK263 | PVG → HKG | May 16, 19:55 UTC | May 16, 20:20 UTC | 25m |
| 2026-05-16 | CKK222 | LAX → PVG | May 16, 01:50 UTC | May 16, 19:20 UTC | 17h 31m |
| 2026-05-15 | CKK222 | LAX → PVG | May 15, 23:20 UTC | May 16, 19:20 UTC | 20h 1m |
| 2026-05-15 | CKK222 | LAX → PVG | May 15, 21:35 UTC | May 16, 19:20 UTC | 21h 46m |
| 2026-05-15 | CKK221 | PVG → LAX | May 15, 01:20 UTC | May 15, 19:00 UTC | 17h 40m |
| 2026-05-14 | CKK241 | PVG → NRT | May 14, 05:15 UTC | May 14, 23:05 UTC | 17h 50m |
| 2026-05-13 | CKK226 | LAX → PVG | May 13, 23:20 UTC | May 14, 23:05 UTC | 23h 45m |
| 2026-05-13 | CKK226 | LAX → PVG | May 13, 17:10 UTC | May 14, 06:40 UTC | 13h 30m |
| 2026-05-13 | CKK225 | PVG → LAX | May 13, 09:10 UTC | May 13, 14:40 UTC | 5h 30m |
| 2026-05-13 | CKK225 | PVG → LAX | May 13, 00:45 UTC | May 13, 08:00 UTC | 7h 15m |
| 2026-05-12 | CKK225 | PVG → LAX | May 12, 07:55 UTC | May 13, 07:15 UTC | 23h 20m |
| 2026-05-11 | CKK222 | LAX → PVG | May 11, 20:55 UTC | May 12, 08:25 UTC | 11h 30m |
| 2026-05-11 | CKK221 | PVG → LAX | May 11, 08:05 UTC | May 11, 18:10 UTC | 10h 5m |
| 2026-05-10 | CKK221 | PVG → LAX | May 10, 17:20 UTC | May 11, 17:15 UTC | 23h 56m |
| 2026-05-10 | CKK221 | PVG → LAX | May 10, 15:19 UTC | May 11, 09:20 UTC | 18h 0m |
| 2026-05-10 | CKK210 | AMS → PVG | May 10, 13:19 UTC | May 11, 09:20 UTC | 20h 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.
Prefer a tail-number view? See the B-221W page for operator, model, and routing details .