Apparatus

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sensors Mode-S transponder

71C523

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

Currently assigned to HL8523 · BOEING 737 MAX 8

Hex
71C523
Octal
34342443
Decimal
7,456,035
Country
KR
Tail
HL8523
Type
B38M
Transponder active on ground
Flights observed
433
Distinct callsigns
20
Country
KR
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 71C523.

Country allocation

The ICAO 24-bit address 71C523 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
JJA1301 - 25 2026-07-13
JJA1108 - 25 2026-07-12
JJA1802 - 24 2026-07-13
JJA1107 - 24 2026-07-12
JJA1302 - 23 2026-07-13
JJA2504 - 21 2026-07-12
JJA2503 - 21 2026-07-11
JJA8501 - 20 2026-07-12
JJA6013 - 20 2026-07-08
JJA1801 - 20 2026-07-13
JJA8502 - 16 2026-07-12
JJA1103 - 16 2026-07-11
JJA1203 - 13 2026-07-10
JJA1104 - 13 2026-07-11
JJA6014 Jeju Air 12 2026-07-08
JJA1204 - 10 2026-07-10
JJA1106 - 9 2026-07-06
JJA1105 - 9 2026-07-06
JJA8402 - 8 2026-07-06
JJA1406 - 8 2026-07-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-13 JJA1301 ICN → KIX Jul 13, 22:25 UTCJul 13, 23:45 UTC1h 20m
2026-07-13 JJA1802 - Jul 13, 08:40 UTCJul 13, 10:25 UTC1h 45m
2026-07-13 JJA1801 - Jul 13, 04:35 UTCJul 13, 06:20 UTC1h 45m
2026-07-13 JJA1302 - Jul 13, 01:20 UTCJul 13, 02:45 UTC1h 25m
2026-07-12 JJA1301 ICN → KIX Jul 12, 22:25 UTCJul 12, 23:45 UTC1h 20m
2026-07-12 JJA1108 NRT → ICN Jul 12, 11:01 UTCJul 12, 12:50 UTC1h 50m
2026-07-12 JJA1107 ICN → NRT Jul 12, 07:40 UTCJul 12, 09:35 UTC1h 55m
2026-07-12 JJA8502 - Jul 12, 05:55 UTCJul 12, 06:15 UTC20m
2026-07-12 JJA8501 - Jul 12, 03:40 UTCJul 12, 03:55 UTC15m
2026-07-12 JJA2504 - Jul 12, 01:50 UTCJul 12, 02:10 UTC20m
2026-07-11 JJA2504 - Jul 11, 22:20 UTCJul 11, 22:35 UTC15m
2026-07-11 JJA2504 - Jul 11, 21:00 UTCJul 11, 21:10 UTC10m
2026-07-11 JJA2503 - Jul 11, 19:10 UTCJul 11, 19:20 UTC10m
2026-07-11 JJA2503 - Jul 11, 13:40 UTCJul 11, 16:30 UTC2h 50m
2026-07-11 JJA1104 NRT → ICN Jul 11, 05:35 UTCJul 11, 07:30 UTC1h 55m
2026-07-11 JJA1103 ICN → NRT Jul 11, 01:50 UTCJul 11, 03:45 UTC1h 55m
2026-07-10 JJA1204 - Jul 10, 09:15 UTCJul 10, 10:45 UTC1h 30m
2026-07-10 JJA1203 - Jul 10, 06:25 UTCJul 10, 07:45 UTC1h 20m
2026-07-10 JJA1404 - Jul 10, 03:30 UTCJul 10, 04:35 UTC1h 5m
2026-07-10 JJA1403 - Jul 10, 01:15 UTCJul 10, 02:00 UTC45m
2026-07-09 JJA2504 - Jul 9, 18:40 UTCJul 9, 23:55 UTC5h 15m
2026-07-09 JJA2503 ICN → BKK Jul 9, 12:05 UTCJul 9, 17:10 UTC5h 5m
2026-07-09 JJA1802 - Jul 9, 09:40 UTCJul 9, 10:20 UTC40m
2026-07-09 JJA1802 - Jul 9, 08:35 UTCJul 9, 08:45 UTC10m
2026-07-09 JJA1801 - Jul 9, 04:45 UTCJul 9, 06:25 UTC1h 40m
2026-07-09 JJA1302 KIX → ICN Jul 9, 01:10 UTCJul 9, 02:35 UTC1h 25m
2026-07-08 JJA1301 ICN → KIX Jul 8, 22:20 UTCJul 8, 23:50 UTC1h 30m
2026-07-08 JJA6014 HKG → ICN Jul 8, 17:20 UTCJul 8, 20:25 UTC3h 5m
2026-07-08 JJA6013 ICN → HKG Jul 8, 12:15 UTCJul 8, 15:30 UTC3h 15m
2026-07-08 JJA1406 - Jul 8, 09:05 UTCJul 8, 10:05 UTC1h 0m
2026-07-08 JJA1405 - Jul 8, 06:40 UTCJul 8, 07:25 UTC45m
2026-07-08 JJA1502 - Jul 8, 02:10 UTCJul 8, 04:35 UTC2h 25m
2026-07-07 JJA1501 - Jul 7, 22:25 UTCJul 8, 00:45 UTC2h 20m
2026-07-07 JJA6014 HKG → ICN Jul 7, 16:50 UTCJul 7, 20:00 UTC3h 10m
2026-07-07 JJA6013 ICN → HKG Jul 7, 12:10 UTCJul 7, 15:20 UTC3h 10m
2026-07-07 JJA1104 NRT → ICN Jul 7, 05:30 UTCJul 7, 07:30 UTC2h 0m
2026-07-07 JJA1103 ICN → NRT Jul 7, 01:45 UTCJul 7, 03:40 UTC1h 55m
2026-07-06 JJA2108 - Jul 6, 17:55 UTCJul 6, 21:45 UTC3h 50m
2026-07-06 JJA2107 ICN → CRK Jul 6, 12:55 UTCJul 6, 16:15 UTC3h 20m
2026-07-06 JJA1106 NRT → ICN Jul 6, 08:35 UTCJul 6, 10:40 UTC2h 5m
2026-07-06 JJA1105 ICN → NRT Jul 6, 05:00 UTCJul 6, 07:00 UTC2h 0m
2026-07-06 JJA8402 - Jul 6, 03:05 UTCJul 6, 03:25 UTC20m
2026-07-05 JJA8401 - Jul 5, 23:25 UTCJul 5, 23:45 UTC20m
2026-07-05 JJA1108 NRT → ICN Jul 5, 10:05 UTCJul 5, 12:10 UTC2h 5m
2026-07-05 JJA1107 ICN → NRT Jul 5, 06:25 UTCJul 5, 08:15 UTC1h 50m
2026-07-05 JJA8502 - Jul 5, 04:25 UTCJul 5, 04:55 UTC30m
2026-07-05 JJA8501 - Jul 5, 01:55 UTCJul 5, 02:20 UTC25m
2026-07-04 JJA2504 - Jul 4, 18:40 UTCJul 4, 23:40 UTC5h 0m
2026-07-04 JJA2503 ICN → BKK Jul 4, 11:40 UTCJul 4, 16:55 UTC5h 15m
2026-07-04 JJA1104 NRT → ICN Jul 4, 05:35 UTCJul 4, 07:35 UTC2h 0m

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 HL8523 page for operator, model, and routing details .

Mode-S 71C523 frequently asked

What is Mode-S code 71C523?
71C523 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8523.
Where is Mode-S 71C523 registered?
Mode-S code 71C523 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 71C523 broadcasting right now?
Mode-S 71C523 is currently broadcasting from the ground.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C523, octal 34342443, decimal 7,456,035.
What flights does 71C523 operate?
Mode-S 71C523 has broadcast 20 distinct callsigns, including JJA1301, JJA1108, JJA1802, JJA1107, JJA1302.