sensors Mode-S transponder
781E21
ICAO 24-bit transponder address · allocated to China
Currently assigned to B-652Q · GULFSTREAM 4
- Hex
- 781E21
- Octal
- 36017041
- Decimal
- 7,872,033
- Country
- CN
- Tail
- B-652Q
- Type
- GLF4
- Flights observed
- 81
- Distinct callsigns
- 2
- Country
- CN
- Last broadcast
- 19h ago
Last known position
Country allocation
The ICAO 24-bit address 781E21 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 2 distinct
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-13 | B652Q | HND → HKG | Jul 13, 11:40 UTC | Jul 13, 15:30 UTC | 3h 50m |
| 2026-07-12 | B652Q | - | Jul 12, 12:40 UTC | Jul 12, 14:40 UTC | 2h 0m |
| 2026-07-09 | B652Q | - | Jul 9, 04:50 UTC | Jul 9, 05:00 UTC | 10m |
| 2026-07-08 | B652Q | - | Jul 8, 12:55 UTC | Jul 9, 03:25 UTC | 14h 30m |
| 2026-07-08 | B652Q | - | Jul 8, 05:50 UTC | Jul 8, 11:40 UTC | 5h 50m |
| 2026-07-07 | B652Q | - | Jul 7, 10:30 UTC | Jul 8, 04:45 UTC | 18h 15m |
| 2026-07-07 | B652Q | - | Jul 7, 10:05 UTC | Jul 8, 04:45 UTC | 18h 40m |
| 2026-07-07 | B652Q | - | Jul 7, 07:00 UTC | Jul 7, 07:55 UTC | 55m |
| 2026-07-01 | B652Q | - | Jul 1, 03:45 UTC | Jul 1, 03:55 UTC | 10m |
| 2026-06-30 | B652Q | - | Jun 30, 03:10 UTC | Jun 30, 04:45 UTC | 1h 35m |
| 2026-06-29 | B652Q | - | Jun 29, 06:24 UTC | Jun 29, 08:54 UTC | 2h 30m |
| 2026-06-28 | B652Q | - | Jun 28, 02:29 UTC | Jun 28, 14:25 UTC | 11h 55m |
| 2026-06-27 | B652Q | - | Jun 27, 02:50 UTC | Jun 27, 07:49 UTC | 5h 0m |
| 2026-06-26 | B652Q | - | Jun 26, 21:04 UTC | Jun 27, 00:00 UTC | 2h 55m |
| 2026-06-26 | B652Q | - | Jun 26, 11:00 UTC | Jun 26, 11:14 UTC | 15m |
| 2026-06-25 | B652Q | - | Jun 25, 08:20 UTC | Jun 25, 09:05 UTC | 45m |
| 2026-06-25 | B652Q | - | Jun 25, 00:40 UTC | Jun 25, 00:55 UTC | 15m |
| 2026-06-24 | B652Q | - | Jun 24, 09:24 UTC | Jun 24, 10:10 UTC | 45m |
| 2026-06-24 | B652Q | - | Jun 24, 07:05 UTC | Jun 24, 07:20 UTC | 15m |
| 2026-06-23 | B652Q | - | Jun 23, 10:10 UTC | Jun 23, 10:19 UTC | 10m |
| 2026-06-22 | B652Q | - | Jun 22, 07:45 UTC | Jun 22, 09:40 UTC | 1h 55m |
| 2026-06-21 | B652Q | - | Jun 21, 14:10 UTC | Jun 21, 14:44 UTC | 35m |
| 2026-06-19 | B652Q | - | Jun 19, 09:49 UTC | Jun 19, 10:29 UTC | 40m |
| 2026-06-18 | TCI088 | - | Jun 18, 08:30 UTC | Jun 18, 15:15 UTC | 6h 45m |
| 2026-06-18 | TCI088 | - | Jun 18, 05:05 UTC | Jun 18, 06:45 UTC | 1h 40m |
| 2026-06-17 | B652Q | - | Jun 17, 05:05 UTC | Jun 17, 05:40 UTC | 35m |
| 2026-06-16 | B652Q | - | Jun 16, 23:10 UTC | Jun 17, 03:15 UTC | 4h 5m |
| 2026-06-15 | B652Q | - | Jun 15, 06:20 UTC | Jun 15, 06:40 UTC | 20m |
| 2026-06-12 | B652Q | - | Jun 12, 22:45 UTC | Jun 12, 23:15 UTC | 30m |
| 2026-06-12 | B652Q | - | Jun 12, 13:30 UTC | Jun 12, 14:15 UTC | 45m |
| 2026-06-11 | B652Q | - | Jun 11, 09:15 UTC | Jun 11, 09:25 UTC | 10m |
| 2026-06-08 | B652Q | - | Jun 8, 23:30 UTC | Jun 8, 23:45 UTC | 15m |
| 2026-06-06 | B652Q | - | Jun 6, 12:14 UTC | Jun 6, 13:00 UTC | 45m |
| 2026-06-06 | B652Q | - | Jun 6, 10:30 UTC | Jun 6, 10:50 UTC | 20m |
| 2026-06-03 | B652Q | - | Jun 3, 12:45 UTC | Jun 3, 13:05 UTC | 20m |
| 2026-06-03 | B652Q | - | Jun 3, 09:30 UTC | Jun 3, 10:50 UTC | 1h 20m |
| 2026-06-03 | B652Q | - | Jun 3, 05:15 UTC | Jun 3, 07:35 UTC | 2h 20m |
| 2026-06-02 | B652Q | - | Jun 2, 09:35 UTC | Jun 2, 09:50 UTC | 15m |
| 2026-06-02 | B652Q | - | Jun 2, 06:25 UTC | Jun 2, 06:40 UTC | 15m |
| 2026-05-28 | B652Q | - | May 28, 08:00 UTC | May 28, 08:15 UTC | 15m |
| 2026-05-28 | B652Q | - | May 28, 04:55 UTC | May 28, 05:10 UTC | 15m |
| 2026-05-28 | B652Q | - | May 28, 03:15 UTC | May 28, 03:35 UTC | 20m |
| 2026-05-27 | B652Q | - | May 27, 08:15 UTC | May 27, 08:35 UTC | 20m |
| 2026-05-27 | B652Q | - | May 27, 03:14 UTC | May 27, 06:34 UTC | 3h 20m |
| 2026-05-26 | B652Q | - | May 26, 09:45 UTC | May 26, 09:59 UTC | 15m |
| 2026-05-26 | B652Q | - | May 26, 05:59 UTC | May 26, 09:04 UTC | 3h 5m |
| 2026-05-25 | B652Q | - | May 25, 09:55 UTC | May 25, 14:30 UTC | 4h 35m |
| 2026-05-24 | B652Q | - | May 24, 08:00 UTC | May 24, 09:15 UTC | 1h 15m |
| 2026-05-24 | B652Q | - | May 24, 03:00 UTC | May 24, 03:10 UTC | 10m |
| 2026-05-22 | B652Q | - | May 22, 05:00 UTC | May 22, 06:05 UTC | 1h 5m |
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-652Q page for operator, model, and routing details .