Apparatus

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sensors Mode-S transponder

71C399

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

Currently assigned to HL8399 · AIRBUS A-321neo

Hex
71C399
Octal
34341631
Decimal
7,455,641
Country
KR
Tail
HL8399
Type
A21N
Broadcasting now · callsign AAR722 · 35,000 ft
Flights observed
176
Distinct callsigns
20
Country
KR
Last broadcast
1h ago

Current position

71C399 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 71C399 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
AAR722 Asiana Airlines 26 2026-05-30
AAR721 Asiana Airlines 26 2026-05-30
AAR755 Asiana Airlines 21 2026-05-28
AAR744 Asiana Airlines 12 2026-05-22
AAR743 Asiana Airlines 12 2026-05-21
AAR736 Asiana Airlines 10 2026-05-26
AAR735 Asiana Airlines 10 2026-05-27
AAR756 Asiana Airlines 7 2026-05-29
AAR118 Asiana Airlines 6 2026-05-23
AAR117 Asiana Airlines 6 2026-05-23
AAR173 Asiana Airlines 5 2026-05-26
AAR174 Asiana Airlines 4 2026-05-26
AAR322 Asiana Airlines 3 2026-05-08
AAR152 Asiana Airlines 3 2026-05-05
AAR371 Asiana Airlines 2 2026-05-02
AAR340 Asiana Airlines 2 2026-05-28
AAR339 Asiana Airlines 2 2026-05-28
AAR321 Asiana Airlines 2 2026-05-08
AAR151 Asiana Airlines 2 2026-05-05
AAR568 Asiana Airlines 1 2026-04-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 AAR722 HKG → ICN May 30, 05:20 UTCMay 30, 06:15 UTC55m
2026-05-30 AAR721 ICN → HKG May 30, 00:35 UTCMay 30, 03:35 UTC3h 0m
2026-05-29 AAR756 DAD → ICN May 29, 10:30 UTCMay 29, 20:25 UTC9h 55m
2026-05-29 AAR722 HKG → ICN May 29, 05:20 UTCMay 29, 08:25 UTC3h 5m
2026-05-29 AAR721 ICN → HKG May 29, 00:40 UTCMay 29, 03:45 UTC3h 5m
2026-05-28 AAR755 ICN → DAD May 28, 10:20 UTCMay 28, 20:25 UTC10h 5m
2026-05-28 AAR340 HRB → ICN May 28, 08:25 UTCMay 28, 08:45 UTC20m
2026-05-28 AAR339 ICN → HRB May 28, 03:45 UTCMay 28, 04:10 UTC25m
2026-05-27 AAR735 ICN → SGN May 27, 10:50 UTCMay 27, 22:45 UTC11h 55m
2026-05-27 AAR722 HKG → ICN May 27, 05:19 UTCMay 27, 08:35 UTC3h 16m
2026-05-27 AAR721 ICN → HKG May 27, 00:44 UTCMay 27, 03:45 UTC3h 0m
2026-05-26 AAR736 SGN → ICN May 26, 22:09 UTCMay 26, 22:44 UTC35m
2026-05-26 AAR735 ICN → SGN May 26, 10:54 UTCMay 26, 20:54 UTC10h 0m
2026-05-26 AAR173 CTS → ICN May 26, 06:10 UTCMay 26, 08:39 UTC2h 30m
2026-05-26 AAR174 ICN → CTS May 26, 01:55 UTCMay 26, 04:15 UTC2h 20m
2026-05-25 AAR755 ICN → DAD May 25, 10:20 UTCMay 25, 20:55 UTC10h 34m
2026-05-24 AAR756 DAD → ICN May 24, 20:00 UTCMay 24, 20:30 UTC30m
2026-05-24 AAR755 ICN → DAD May 24, 10:20 UTCMay 24, 18:45 UTC8h 25m
2026-05-24 - ICN → ICN May 24, 10:05 UTCMay 24, 10:15 UTC10m
2026-05-24 AAR722 HKG → ICN May 24, 05:20 UTCMay 24, 08:35 UTC3h 15m
2026-05-24 AAR721 ICN → HKG May 24, 00:30 UTCMay 24, 03:35 UTC3h 5m
2026-05-23 AAR117 KIX → ICN May 23, 15:15 UTCMay 23, 16:40 UTC1h 25m
2026-05-23 AAR118 ICN → KIX May 23, 12:00 UTCMay 23, 13:15 UTC1h 15m
2026-05-22 AAR744 BKK → ICN May 22, 05:50 UTCMay 22, 11:10 UTC5h 20m
2026-05-21 AAR743 ICN → BKK May 21, 22:55 UTCMay 22, 04:15 UTC5h 20m
2026-05-21 AAR755 ICN → DAD May 21, 10:30 UTCMay 21, 20:30 UTC10h 0m
2026-05-20 AAR117 KIX → ICN May 20, 15:35 UTCMay 20, 17:05 UTC1h 30m
2026-05-20 AAR118 ICN → KIX May 20, 12:25 UTCMay 20, 13:35 UTC1h 10m
2026-05-20 AAR744 BKK → ICN May 20, 05:30 UTCMay 20, 10:35 UTC5h 5m
2026-05-19 AAR743 ICN → BKK May 19, 22:45 UTCMay 20, 04:00 UTC5h 15m
2026-05-19 AAR744 BKK → ICN May 19, 05:10 UTCMay 19, 10:20 UTC5h 10m
2026-05-18 AAR743 ICN → BKK May 18, 22:20 UTCMay 19, 03:30 UTC5h 10m
2026-05-18 AAR117 KIX → ICN May 18, 15:30 UTCMay 18, 16:50 UTC1h 20m
2026-05-18 AAR118 ICN → KIX May 18, 11:55 UTCMay 18, 13:20 UTC1h 25m
2026-05-18 AAR744 BKK → ICN May 18, 05:05 UTCMay 18, 10:25 UTC5h 20m
2026-05-17 AAR743 ICN → BKK May 17, 22:30 UTCMay 18, 03:35 UTC5h 5m
2026-05-17 AAR117 KIX → ICN May 17, 15:25 UTCMay 17, 16:40 UTC1h 15m
2026-05-17 AAR118 ICN → KIX May 17, 12:05 UTCMay 17, 13:25 UTC1h 20m
2026-05-17 AAR744 BKK → ICN May 17, 05:25 UTCMay 17, 10:40 UTC5h 15m
2026-05-16 AAR743 ICN → BKK May 16, 22:35 UTCMay 17, 03:45 UTC5h 10m
2026-05-16 AAR117 KIX → ICN May 16, 15:35 UTCMay 16, 16:50 UTC1h 15m
2026-05-16 AAR118 ICN → KIX May 16, 12:16 UTCMay 16, 13:41 UTC1h 25m
2026-05-16 AAR744 BKK → ICN May 16, 05:15 UTCMay 16, 10:31 UTC5h 16m
2026-05-15 AAR743 ICN → BKK May 15, 22:25 UTCMay 16, 03:40 UTC5h 15m
2026-05-15 AAR336 PEK → ICN May 15, 10:50 UTCMay 15, 11:10 UTC20m
2026-05-15 AAR335 ICN → PEK May 15, 06:25 UTCMay 15, 06:45 UTC20m
2026-05-15 AAR332 PEK → ICN May 15, 04:05 UTCMay 15, 04:25 UTC20m
2026-05-14 AAR331 ICN → PEK May 14, 23:40 UTCMay 15, 00:00 UTC20m
2026-05-14 AAR755 ICN → DAD May 14, 10:15 UTCMay 14, 20:20 UTC10h 5m
2026-05-13 AAR735 ICN → SGN May 13, 10:50 UTCMay 13, 22:35 UTC11h 45m

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 HL8399 page for operator, model, and routing details .

Mode-S 71C399 frequently asked

What is Mode-S code 71C399?
71C399 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8399.
Where is Mode-S 71C399 registered?
Mode-S code 71C399 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 71C399 broadcasting right now?
Yes. Mode-S 71C399 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C399, octal 34341631, decimal 7,455,641.
What flights does 71C399 operate?
Mode-S 71C399 has broadcast 20 distinct callsigns, including AAR722, AAR721, AAR755, AAR744, AAR743.