Apparatus

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sensors Mode-S transponder

71C521

ICAO 24-bit transponder address · allocated to Korea, South

Currently assigned to HL8521 · AIRBUS A-350-900

Hex
71C521
Octal
34342441
Decimal
7,456,033
Country
KR
Tail
HL8521
Type
A359
No current signal · last broadcast Jul 26, 22:15 UTC
Flights observed
266
Distinct callsigns
20
Country
KR
Last broadcast
Jul 26, 22:15 UTC

Last known position

Most recent position reported by Mode-S 71C521.

Country allocation

The ICAO 24-bit address 71C521 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
AAR761 Asiana Airlines 16 2026-07-26
AAR502 Asiana Airlines 16 2026-07-25
AAR501 Asiana Airlines 16 2026-07-25
AAR542 Asiana Airlines 14 2026-07-24
AAR751 Asiana Airlines 13 2026-07-24
AAR541 Asiana Airlines 13 2026-07-23
AAR522 - 13 2026-06-27
AAR547 - 11 2026-06-17
AAR752 Asiana Airlines 10 2026-07-24
AAR548 - 10 2026-06-18
AAR521 Asiana Airlines 10 2026-06-25
AAR511 Asiana Airlines 10 2026-06-09
AAR762 Asiana Airlines 9 2026-07-26
AAR582 - 8 2026-07-03
AAR546 Asiana Airlines 8 2026-06-12
AAR512 Asiana Airlines 8 2026-06-10
AAR211 Asiana Airlines 8 2026-05-25
AAR581 - 7 2026-07-02
AAR545 Asiana Airlines 7 2026-06-11
AAR212 Asiana Airlines 7 2026-05-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 AAR762 CGK → ICN Jul 26, 17:00 UTCJul 26, 22:15 UTC5h 15m
2026-07-26 AAR762 CGK → ICN Jul 26, 15:20 UTCJul 26, 15:30 UTC10m
2026-07-26 AAR761 ICN → CGK Jul 26, 13:00 UTCJul 26, 13:25 UTC25m
2026-07-26 AAR761 ICN → CGK Jul 26, 07:10 UTCJul 26, 11:45 UTC4h 35m
2026-07-25 AAR502 CDG → ICN Jul 25, 17:40 UTCJul 26, 05:00 UTC11h 20m
2026-07-25 AAR501 ICN → CDG Jul 25, 02:55 UTCJul 25, 14:45 UTC11h 50m
2026-07-25 AAR501 ICN → CDG Jul 25, 01:45 UTCJul 25, 02:10 UTC25m
2026-07-24 AAR752 SIN → ICN Jul 24, 17:10 UTCJul 24, 22:15 UTC5h 5m
2026-07-24 AAR751 ICN → SIN Jul 24, 07:45 UTCJul 24, 12:10 UTC4h 25m
2026-07-24 AAR542 FRA → ICN Jul 24, 04:30 UTCJul 24, 04:55 UTC25m
2026-07-23 AAR542 FRA → ICN Jul 23, 18:10 UTCJul 24, 03:40 UTC9h 30m
2026-07-23 AAR541 ICN → FRA Jul 23, 04:05 UTCJul 23, 15:45 UTC11h 40m
2026-07-23 AAR541 ICN → FRA Jul 23, 02:50 UTCJul 23, 03:15 UTC25m
2026-07-22 AAR742 BKK → ICN Jul 22, 19:45 UTCJul 23, 00:35 UTC4h 50m
2026-07-22 AAR741 ICN → BKK Jul 22, 11:10 UTCJul 22, 16:10 UTC5h 0m
2026-07-22 AAR102 ICN → NRT Jul 22, 01:50 UTCJul 22, 03:50 UTC2h 0m
2026-07-21 AAR752 SIN → ICN Jul 21, 18:10 UTCJul 21, 21:05 UTC2h 55m
2026-07-21 AAR751 ICN → SIN Jul 21, 12:55 UTCJul 21, 13:05 UTC10m
2026-07-21 AAR751 ICN → SIN Jul 21, 07:35 UTCJul 21, 10:15 UTC2h 40m
2026-07-21 AAR502 CDG → ICN Jul 21, 04:00 UTCJul 21, 04:20 UTC20m
2026-07-20 AAR502 CDG → ICN Jul 20, 17:25 UTCJul 21, 03:10 UTC9h 45m
2026-07-20 AAR501 ICN → CDG Jul 20, 01:35 UTCJul 20, 15:15 UTC13h 40m
2026-07-19 AAR203 LAX → ICN Jul 19, 06:35 UTCJul 19, 18:20 UTC11h 45m
2026-07-18 AAR204 ICN → LAX Jul 18, 13:25 UTCJul 19, 00:35 UTC11h 10m
2026-07-06 AAR502 - Jul 6, 04:35 UTCJul 6, 05:00 UTC25m
2026-07-05 AAR502 - Jul 5, 17:40 UTCJul 6, 03:45 UTC10h 5m
2026-07-05 AAR501 - Jul 5, 02:45 UTCJul 5, 14:45 UTC12h 0m
2026-07-05 AAR501 - Jul 5, 01:35 UTCJul 5, 01:55 UTC20m
2026-07-04 AAR203 - Jul 4, 06:20 UTCJul 4, 18:40 UTC12h 20m
2026-07-03 AAR204 - Jul 3, 14:15 UTCJul 4, 00:40 UTC10h 25m
2026-07-03 AAR582 - Jul 3, 07:05 UTCJul 3, 07:25 UTC20m
2026-07-02 AAR582 - Jul 2, 20:25 UTCJul 3, 06:05 UTC9h 40m
2026-07-02 AAR581 - Jul 2, 13:45 UTCJul 2, 18:05 UTC4h 20m
2026-07-02 AAR581 - Jul 2, 05:30 UTCJul 2, 05:45 UTC15m
2026-07-02 AAR111 KIX → ICN Jul 2, 01:45 UTCJul 2, 03:15 UTC1h 30m
2026-07-01 AAR112 - Jul 1, 22:10 UTCJul 1, 23:40 UTC1h 30m
2026-07-01 AAR542 - Jul 1, 04:40 UTCJul 1, 05:05 UTC25m
2026-06-30 AAR542 - Jun 30, 17:55 UTCJul 1, 03:45 UTC9h 50m
2026-06-30 AAR541 - Jun 30, 03:40 UTCJun 30, 15:30 UTC11h 50m
2026-06-30 AAR541 - Jun 30, 02:30 UTCJun 30, 02:40 UTC10m
2026-06-29 AAR752 SIN → ICN Jun 29, 18:14 UTCJun 29, 21:14 UTC3h 0m
2026-06-29 AAR752 SIN → ICN Jun 29, 15:04 UTCJun 29, 15:14 UTC10m
2026-06-29 AAR751 - Jun 29, 13:00 UTCJun 29, 13:19 UTC20m
2026-06-29 AAR751 - Jun 29, 07:50 UTCJun 29, 10:29 UTC2h 40m
2026-06-29 AAR502 - Jun 29, 04:55 UTCJun 29, 05:20 UTC25m
2026-06-28 AAR502 - Jun 28, 18:00 UTCJun 29, 04:04 UTC10h 5m
2026-06-28 AAR501 - Jun 28, 02:39 UTCJun 28, 14:45 UTC12h 5m
2026-06-28 AAR501 - Jun 28, 01:29 UTCJun 28, 01:44 UTC15m
2026-06-27 AAR762 - Jun 27, 16:30 UTCJun 27, 21:29 UTC5h 0m
2026-06-27 AAR761 - Jun 27, 12:29 UTCJun 27, 12:45 UTC15m

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 HL8521 page for operator, model, and routing details .

Mode-S 71C521 frequently asked

What is Mode-S code 71C521?
71C521 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8521.
Where is Mode-S 71C521 registered?
Mode-S code 71C521 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 71C521 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C521, octal 34342441, decimal 7,456,033.
What flights does 71C521 operate?
Mode-S 71C521 has broadcast 20 distinct callsigns, including AAR761, AAR502, AAR501, AAR542, AAR751.