sensors Mode-S transponder
781DC3
ICAO 24-bit transponder address · allocated to China
Currently assigned to B-222A · BOEING 737-800
- Hex
- 781DC3
- Octal
- 36016703
- Decimal
- 7,871,939
- Country
- CN
- Tail
- B-222A
- Type
- B738
- Flights observed
- 22
- Distinct callsigns
- 13
- Country
- CN
- Last broadcast
- 10h ago
Last known position
Country allocation
The ICAO 24-bit address 781DC3 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 13 distinct
| Callsign | Airline | Flights | Last seen |
|---|---|---|---|
| RLH6587 | Ruili Airlines | 4 | 2026-05-06 |
| RLH6538 | Ruili Airlines | 4 | 2026-05-18 |
| RLH6531 | Ruili Airlines | 3 | 2026-06-11 |
| RLH6548 | - | 2 | 2026-05-03 |
| RLH6594 | Ruili Airlines | 1 | 2026-04-23 |
| RLH6577 | Ruili Airlines | 1 | 2026-05-17 |
| RLH5044 | Ruili Airlines | 1 | 2026-06-06 |
| RLH5043 | Ruili Airlines | 1 | 2026-06-06 |
| RLH5016 | Ruili Airlines | 1 | 2026-05-07 |
| RLH5015 | Ruili Airlines | 1 | 2026-04-25 |
| RLH5011 | Ruili Airlines | 1 | 2026-06-06 |
| RLH5004 | Ruili Airlines | 1 | 2026-05-28 |
| RLH5003 | Ruili Airlines | 1 | 2026-05-28 |
Recent flights last 22
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-11 | RLH6531 | NNY → HRB | Jun 11, 05:15 UTC | Jun 11, 05:35 UTC | 20m |
| 2026-06-10 | RLH6531 | NNY → HRB | Jun 10, 10:20 UTC | Jun 11, 05:35 UTC | 19h 15m |
| 2026-06-06 | RLH5044 | HPH → KMG | Jun 6, 14:25 UTC | Jun 7, 10:55 UTC | 20h 30m |
| 2026-06-06 | RLH5043 | KMG → HPH | Jun 6, 12:45 UTC | Jun 6, 13:05 UTC | 20m |
| 2026-06-06 | RLH5011 | BAV → TSN | Jun 6, 03:20 UTC | Jun 6, 03:40 UTC | 20m |
| 2026-05-28 | RLH5004 | SZX → WUX | May 28, 09:35 UTC | May 28, 09:45 UTC | 10m |
| 2026-05-28 | RLH5003 | WUX → SZX | May 28, 08:00 UTC | May 28, 08:20 UTC | 20m |
| 2026-05-19 | RLH6531 | NNY → HRB | May 19, 05:05 UTC | May 19, 05:15 UTC | 10m |
| 2026-05-18 | RLH6538 | YNT → KMG | May 18, 09:45 UTC | May 19, 05:15 UTC | 19h 29m |
| 2026-05-18 | RLH6538 | YNT → KMG | May 18, 04:51 UTC | May 18, 10:00 UTC | 5h 10m |
| 2026-05-17 | RLH6577 | KMG → FOC | May 17, 11:45 UTC | May 17, 11:55 UTC | 10m |
| 2026-05-13 | RLH6538 | YNT → KMG | May 13, 09:35 UTC | May 13, 10:10 UTC | 35m |
| 2026-05-07 | RLH5016 | TFU → WUX | May 7, 06:35 UTC | May 7, 10:15 UTC | 3h 40m |
| 2026-05-06 | RLH6587 | SHE → WUT | May 6, 08:55 UTC | May 6, 09:05 UTC | 10m |
| 2026-05-03 | RLH6548 | - | May 3, 08:50 UTC | May 4, 05:35 UTC | 20h 45m |
| 2026-05-03 | RLH6548 | - | May 3, 05:10 UTC | May 3, 09:05 UTC | 3h 55m |
| 2026-04-29 | RLH6587 | SHE → WUT | Apr 29, 08:40 UTC | Apr 29, 08:55 UTC | 15m |
| 2026-04-27 | RLH6538 | YNT → KMG | Apr 27, 09:45 UTC | Apr 28, 06:25 UTC | 20h 40m |
| 2026-04-26 | RLH6587 | SHE → WUT | Apr 26, 08:40 UTC | Apr 26, 08:50 UTC | 10m |
| 2026-04-25 | RLH5015 | WUX → TFU | Apr 25, 06:25 UTC | Apr 25, 10:15 UTC | 3h 50m |
| 2026-04-24 | RLH6587 | SHE → WUT | Apr 24, 08:40 UTC | Apr 24, 08:55 UTC | 15m |
| 2026-04-23 | RLH6594 | CGO → SHE | Apr 23, 15:20 UTC | Apr 23, 15:30 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 B-222A page for operator, model, and routing details .