Apparatus

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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
No current signal · last broadcast 10h ago
Flights observed
247
Distinct callsigns
20
Country
KR
Last broadcast
10h ago

Last known position

Most recent position reported by Mode-S 71BC21.

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 - 24 2026-07-13
AIH242 - 17 2026-06-17
AIH286 - 14 2026-07-01
AIH795 - 12 2026-07-15
AIH396 - 12 2026-07-02
AIH247 - 12 2026-07-13
AIH969 - 10 2026-06-26
AIH793 - 9 2026-06-15
AIH967 - 7 2026-07-16
AIH796 - 7 2026-07-15
AIH794 - 7 2026-06-15
AIH395 - 7 2026-07-02
AIH968 - 6 2026-07-16
AIH790 - 6 2026-07-10
AIH789 - 6 2026-07-10
AIH775 - 6 2026-06-25
AIH2851 - 6 2026-07-01
AIH284 - 6 2026-06-23
AIH970 - 5 2026-06-26
AIH776 - 5 2026-06-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 AIH285 - Jul 17, 11:55 UTCJul 17, 22:49 UTC10h 55m
2026-07-17 AIH2861 LAX → SFO Jul 17, 08:20 UTCJul 17, 09:10 UTC50m
2026-07-17 AIH2861 LAX → SFO Jul 17, 01:05 UTCJul 17, 06:00 UTC4h 55m
2026-07-16 AIH2861 LAX → SFO Jul 16, 15:10 UTCJul 16, 22:49 UTC7h 40m
2026-07-16 AIH968 HKG → ICN Jul 16, 06:45 UTCJul 16, 09:50 UTC3h 5m
2026-07-16 AIH967 ICN → HKG Jul 16, 00:45 UTCJul 16, 03:35 UTC2h 50m
2026-07-15 AIH796 FRA → ICN Jul 15, 10:40 UTCJul 15, 21:15 UTC10h 35m
2026-07-15 AIH795 VIE → FRA Jul 15, 07:00 UTCJul 15, 08:10 UTC1h 10m
2026-07-14 AIH795 ICN → VIE Jul 14, 14:55 UTCJul 15, 05:00 UTC14h 4m
2026-07-13 AIH247 ANC → ICN Jul 13, 22:40 UTCJul 14, 07:15 UTC8h 35m
2026-07-13 AIH247 ATL → ANC Jul 13, 14:00 UTCJul 13, 20:50 UTC6h 50m
2026-07-13 AIH248 ORD → ATL Jul 13, 09:45 UTCJul 13, 11:10 UTC1h 25m
2026-07-13 AIH248 ANC → ORD Jul 13, 01:15 UTCJul 13, 06:40 UTC5h 25m
2026-07-12 AIH248 ICN → ANC Jul 12, 16:20 UTCJul 12, 23:50 UTC7h 30m
2026-07-12 AIH938 ICN → ICN Jul 12, 06:45 UTCJul 12, 13:30 UTC6h 45m
2026-07-10 AIH790 - Jul 10, 21:25 UTCJul 10, 21:45 UTC20m
2026-07-10 AIH790 - Jul 10, 11:15 UTCJul 10, 20:25 UTC9h 10m
2026-07-10 AIH789 VIE → MXP Jul 10, 06:40 UTCJul 10, 07:45 UTC1h 5m
2026-07-09 AIH789 - Jul 9, 14:25 UTCJul 10, 04:25 UTC14h 0m
2026-07-08 AIH796 - Jul 8, 11:05 UTCJul 8, 13:05 UTC2h 0m
2026-07-08 AIH795 VIE → FRA Jul 8, 07:30 UTCJul 8, 08:40 UTC1h 10m
2026-07-07 AIH795 ICN → VIE Jul 7, 15:30 UTCJul 8, 05:30 UTC14h 0m
2026-07-07 AIH968 HKG → ICN Jul 7, 06:10 UTCJul 7, 09:05 UTC2h 55m
2026-07-07 AIH967 ICN → HKG Jul 7, 00:25 UTCJul 7, 03:30 UTC3h 5m
2026-07-05 AIH954 HKG → ICN Jul 5, 01:50 UTCJul 5, 04:55 UTC3h 5m
2026-07-04 AIH954 - Jul 4, 22:40 UTCJul 4, 23:20 UTC40m
2026-07-04 AIH954 - Jul 4, 21:40 UTCJul 4, 22:00 UTC20m
2026-07-04 AIH953 - Jul 4, 15:15 UTCJul 4, 18:55 UTC3h 40m
2026-07-04 AIH952 HKG → ICN Jul 4, 02:00 UTCJul 4, 05:15 UTC3h 15m
2026-07-03 AIH952 - Jul 3, 22:30 UTCJul 3, 22:55 UTC25m
2026-07-03 AIH952 - Jul 3, 21:30 UTCJul 3, 21:50 UTC20m
2026-07-03 AIH951 - Jul 3, 15:25 UTCJul 3, 19:00 UTC3h 35m
2026-07-03 AIH988 ICN → ICN Jul 3, 00:10 UTCJul 3, 06:45 UTC6h 35m
2026-07-02 AIH396 - Jul 2, 16:45 UTCJul 2, 21:40 UTC4h 55m
2026-07-02 AIH396 - Jul 2, 12:00 UTCJul 2, 14:15 UTC2h 15m
2026-07-02 AIH395 - Jul 2, 08:50 UTCJul 2, 09:15 UTC25m
2026-07-02 AIH395 - Jul 2, 03:45 UTCJul 2, 06:00 UTC2h 15m
2026-07-01 AIH2851 ANC → ICN Jul 1, 16:15 UTCJul 2, 00:30 UTC8h 15m
2026-07-01 AIH2851 SFO → ANC Jul 1, 10:15 UTCJul 1, 14:40 UTC4h 25m
2026-07-01 AIH286 - Jul 1, 06:25 UTCJul 1, 07:20 UTC55m
2026-06-30 AIH286 - Jun 30, 16:40 UTCJul 1, 03:10 UTC10h 30m
2026-06-30 AIH958 ICN → ICN Jun 30, 07:05 UTCJun 30, 14:25 UTC7h 20m
2026-06-29 AIH247 - Jun 29, 19:49 UTCJun 30, 04:05 UTC8h 15m
2026-06-29 AIH247 ATL → ANC Jun 29, 11:20 UTCJun 29, 17:49 UTC6h 30m
2026-06-29 AIH248 ORD → ATL Jun 29, 07:30 UTCJun 29, 09:00 UTC1h 30m
2026-06-28 AIH248 - Jun 28, 23:25 UTCJun 29, 04:55 UTC5h 30m
2026-06-28 AIH248 - Jun 28, 14:19 UTCJun 28, 21:40 UTC7h 20m
2026-06-27 AIH2931 ORD → ICN Jun 27, 07:04 UTCJun 27, 20:29 UTC13h 25m
2026-06-26 AIH2941 ANC → ORD Jun 26, 22:55 UTCJun 27, 04:29 UTC5h 35m
2026-06-26 AIH2941 - Jun 26, 14:09 UTCJun 26, 21:30 UTC7h 20m

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 .

Mode-S 71BC21 frequently asked

What is Mode-S code 71BC21?
71BC21 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL7421.
Where is Mode-S 71BC21 registered?
Mode-S code 71BC21 is allocated to Korea, South (KR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 71BC21 broadcasting right now?
No active broadcast right now. Last signal was 10h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71BC21, octal 34336041, decimal 7,453,729.
What flights does 71BC21 operate?
Mode-S 71BC21 has broadcast 20 distinct callsigns, including AIH248, AIH242, AIH286, AIH795, AIH396.