sensors Mode-S transponder
71BC21
ICAO 24-bit transponder address · allocated to Korea, South
Currently assigned to HL7421 · BOEING 747-400
- Hex
- 71BC21
- Octal
- 34336041
- Decimal
- 7,453,729
- Country
- KR
- Tail
- HL7421
- Type
- B744
- Flights observed
- 135
- Distinct callsigns
- 20
- Country
- KR
- Last broadcast
- 1h ago
Current position
Country allocation
The ICAO 24-bit address 71BC21 falls within the block assigned to Korea, South (KR) by ICAO Annex 10, Volume III. Every aircraft registered in Korea, South 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 |
|---|---|---|---|
| AIH248 | Alpine Air Chile | 12 | 2026-05-02 |
| AIH795 | Alpine Air Chile | 8 | 2026-05-27 |
| AIH242 | Alpine Air Chile | 8 | 2026-05-20 |
| AIH793 | Alpine Air Chile | 7 | 2026-06-01 |
| AIH396 | - | 6 | 2026-06-02 |
| AIH286 | Alpine Air Chile | 6 | 2026-05-10 |
| AIH796 | Alpine Air Chile | 5 | 2026-05-27 |
| AIH794 | - | 5 | 2026-06-02 |
| AIH587 | Alpine Air Chile | 5 | 2026-05-25 |
| AIH967 | - | 4 | 2026-05-28 |
| AIH790 | - | 4 | 2026-05-29 |
| AIH789 | - | 4 | 2026-05-29 |
| AIH775 | - | 4 | 2026-04-16 |
| AIH588 | Alpine Air Chile | 4 | 2026-05-26 |
| AIH284 | Alpine Air Chile | 4 | 2026-04-28 |
| AIH247 | Alpine Air Chile | 4 | 2026-05-03 |
| AIH244 | Alpine Air Chile | 4 | 2026-05-12 |
| AIH969 | - | 3 | 2026-06-03 |
| AIH968 | - | 3 | 2026-05-30 |
| AIH933 | - | 3 | 2026-04-29 |
Recent flights last 50
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-06-03 | AIH969 | - | Jun 3, 00:55 UTC | Jun 3, 01:20 UTC | 25m |
| 2026-06-02 | AIH396 | BKK → ICN | Jun 2, 17:15 UTC | Jun 2, 22:00 UTC | 4h 45m |
| 2026-06-02 | AIH396 | - | Jun 2, 12:20 UTC | Jun 2, 14:15 UTC | 1h 55m |
| 2026-06-02 | AIH395 | - | Jun 2, 04:00 UTC | Jun 2, 06:30 UTC | 2h 30m |
| 2026-06-02 | AIH794 | - | Jun 2, 00:35 UTC | Jun 2, 00:55 UTC | 20m |
| 2026-06-01 | AIH794 | - | Jun 1, 14:10 UTC | Jun 1, 17:45 UTC | 3h 35m |
| 2026-06-01 | AIH793 | STN → FRA | Jun 1, 10:10 UTC | Jun 1, 11:15 UTC | 1h 5m |
| 2026-05-31 | AIH793 | STN → FRA | May 31, 15:05 UTC | Jun 1, 07:55 UTC | 16h 50m |
| 2026-05-30 | AIH954 | - | May 30, 21:45 UTC | May 30, 23:10 UTC | 1h 25m |
| 2026-05-30 | AIH953 | - | May 30, 18:30 UTC | May 30, 18:45 UTC | 15m |
| 2026-05-30 | AIH953 | - | May 30, 15:05 UTC | May 30, 17:50 UTC | 2h 45m |
| 2026-05-30 | AIH968 | HKG → ICN | May 30, 08:10 UTC | May 30, 11:10 UTC | 3h 0m |
| 2026-05-30 | KJ967 | - | May 30, 02:30 UTC | May 30, 05:30 UTC | 3h 0m |
| 2026-05-29 | AIH790 | - | May 29, 22:40 UTC | May 29, 23:05 UTC | 25m |
| 2026-05-29 | AIH790 | - | May 29, 12:20 UTC | May 29, 22:00 UTC | 9h 40m |
| 2026-05-29 | AIH789 | VIE → MXP | May 29, 08:55 UTC | May 29, 09:55 UTC | 1h 0m |
| 2026-05-28 | AIH789 | - | May 28, 14:15 UTC | May 29, 04:55 UTC | 14h 40m |
| 2026-05-28 | AIH968 | HKG → ICN | May 28, 07:00 UTC | May 28, 10:00 UTC | 3h 0m |
| 2026-05-28 | AIH967 | - | May 28, 04:00 UTC | May 28, 04:15 UTC | 15m |
| 2026-05-28 | AIH967 | - | May 28, 01:20 UTC | May 28, 03:30 UTC | 2h 10m |
| 2026-05-27 | AIH796 | FRA → ICN | May 27, 20:55 UTC | May 27, 21:15 UTC | 20m |
| 2026-05-27 | AIH796 | FRA → ICN | May 27, 10:25 UTC | May 27, 20:15 UTC | 9h 50m |
| 2026-05-27 | AIH795 | VIE → FRA | May 27, 06:29 UTC | May 27, 07:40 UTC | 1h 10m |
| 2026-05-27 | AIH795 | VIE → FRA | May 27, 04:34 UTC | May 27, 04:39 UTC | 5m |
| 2026-05-26 | AIH795 | VIE → FRA | May 26, 14:55 UTC | May 27, 02:24 UTC | 11h 30m |
| 2026-05-26 | AIH588 | BRU → ICN | May 26, 05:40 UTC | May 26, 05:59 UTC | 20m |
| 2026-05-25 | AIH588 | BRU → ICN | May 25, 18:20 UTC | May 26, 04:45 UTC | 10h 25m |
| 2026-05-25 | AIH587 | ANC → JFK | May 25, 09:10 UTC | May 25, 15:55 UTC | 6h 45m |
| 2026-05-24 | AIH587 | ANC → JFK | May 24, 14:35 UTC | May 25, 06:35 UTC | 16h 0m |
| 2026-05-23 | AIH796 | FRA → ICN | May 23, 21:00 UTC | May 23, 21:25 UTC | 25m |
| 2026-05-23 | AIH796 | FRA → ICN | May 23, 10:30 UTC | May 23, 12:40 UTC | 2h 10m |
| 2026-05-23 | AIH795 | VIE → FRA | May 23, 07:05 UTC | May 23, 08:10 UTC | 1h 5m |
| 2026-05-23 | AIH795 | VIE → FRA | May 23, 03:50 UTC | May 23, 04:45 UTC | 55m |
| 2026-05-22 | AIH795 | VIE → FRA | May 22, 14:15 UTC | May 22, 14:25 UTC | 10m |
| 2026-05-22 | AIH970 | HKG → ICN | May 22, 08:25 UTC | May 22, 11:20 UTC | 2h 54m |
| 2026-05-22 | AIH969 | - | May 22, 05:45 UTC | May 22, 06:05 UTC | 20m |
| 2026-05-22 | AIH969 | - | May 22, 03:05 UTC | May 22, 05:15 UTC | 2h 10m |
| 2026-05-21 | AIH988 | ICN → ICN | May 21, 17:25 UTC | May 22, 00:10 UTC | 6h 45m |
| 2026-05-21 | AIH241 | SEA → ICN | May 21, 03:35 UTC | May 21, 14:45 UTC | 11h 10m |
| 2026-05-20 | AIH242 | ANC → ORD | May 20, 21:35 UTC | May 21, 01:15 UTC | 3h 40m |
| 2026-05-20 | AIH242 | ANC → ORD | May 20, 17:10 UTC | May 20, 19:10 UTC | 2h 0m |
| 2026-05-20 | AIH242 | ANC → ORD | May 20, 08:45 UTC | May 20, 13:50 UTC | 5h 5m |
| 2026-05-20 | AIH242 | ANC → ORD | May 20, 00:05 UTC | May 20, 07:25 UTC | 7h 21m |
| 2026-05-19 | AIH396 | - | May 19, 16:40 UTC | May 19, 21:20 UTC | 4h 40m |
| 2026-05-19 | AIH396 | - | May 19, 12:10 UTC | May 19, 14:10 UTC | 2h 0m |
| 2026-05-19 | AIH395 | - | May 19, 03:40 UTC | May 19, 06:05 UTC | 2h 25m |
| 2026-05-19 | AIH794 | - | May 19, 00:15 UTC | May 19, 00:35 UTC | 20m |
| 2026-05-18 | AIH794 | - | May 18, 13:20 UTC | May 18, 23:25 UTC | 10h 4m |
| 2026-05-18 | AIH793 | STN → FRA | May 18, 09:20 UTC | May 18, 10:30 UTC | 1h 10m |
| 2026-05-17 | AIH793 | STN → FRA | May 17, 15:05 UTC | May 18, 07:00 UTC | 15h 55m |
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 HL7421 page for operator, model, and routing details .