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
Broadcasting now · callsign JJA1454 · 2,125 ft
Flights observed
491
Distinct callsigns
20
Country
KR
Last broadcast
Jul 26, 22:45 UTC

Current position

71C523 is currently broadcasting. Map zoomed to live position.

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
JJA1108 Jeju Air 28 2026-07-26
JJA1802 - 27 2026-07-15
JJA1301 Jeju Air 27 2026-07-26
JJA1107 Jeju Air 27 2026-07-26
JJA1302 - 25 2026-07-15
JJA2504 - 23 2026-07-15
JJA2503 - 23 2026-07-15
JJA1801 - 23 2026-07-15
JJA8501 - 21 2026-07-16
JJA6013 - 20 2026-07-08
JJA8502 - 17 2026-07-16
JJA1103 - 16 2026-07-11
JJA1203 - 14 2026-07-16
JJA1104 - 13 2026-07-11
JJA6014 Jeju Air 12 2026-07-08
JJA1204 - 11 2026-07-16
JJA8402 Jeju Air 10 2026-07-23
JJA1106 Jeju Air 10 2026-07-20
JJA1105 Jeju Air 10 2026-07-20
JJA8401 Jeju Air 9 2026-07-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 JJA1301 KIX → ICN Jul 26, 22:25 UTCJul 26, 22:45 UTC20m
2026-07-26 JJA1108 NRT → ICN Jul 26, 10:15 UTCJul 26, 12:15 UTC2h 0m
2026-07-26 JJA1107 NRT → ICN Jul 26, 06:40 UTCJul 26, 08:35 UTC1h 55m
2026-07-26 JJA1404 FUK → ICN Jul 26, 03:40 UTCJul 26, 04:35 UTC55m
2026-07-26 JJA1403 ICN → FUK Jul 26, 01:15 UTCJul 26, 02:05 UTC50m
2026-07-25 JJA1308 KIX → ICN Jul 25, 11:15 UTCJul 25, 12:40 UTC1h 25m
2026-07-25 JJA1307 ICN → KIX Jul 25, 08:25 UTCJul 25, 09:55 UTC1h 30m
2026-07-25 JJA6102 TPE → ICN Jul 25, 04:05 UTCJul 25, 06:15 UTC2h 10m
2026-07-25 JJA6101 ICN → TPE Jul 25, 02:10 UTCJul 25, 02:25 UTC15m
2026-07-25 JJA6101 ICN → TPE Jul 25, 00:25 UTCJul 25, 01:10 UTC45m
2026-07-24 JJA2315 ICN → PQC Jul 24, 08:55 UTCJul 24, 20:55 UTC12h 0m
2026-07-24 JJA1176 NRT → ICN Jul 24, 04:50 UTCJul 24, 06:45 UTC1h 55m
2026-07-24 JJA1175 NRT → PUS Jul 24, 01:15 UTCJul 24, 03:10 UTC1h 55m
2026-07-23 JJA2108 HKG → ICN Jul 23, 18:30 UTCJul 23, 22:10 UTC3h 40m
2026-07-23 JJA2107 ICN → CRK Jul 23, 13:35 UTCJul 23, 16:55 UTC3h 20m
2026-07-23 JJA1108 NRT → ICN Jul 23, 10:05 UTCJul 23, 12:05 UTC2h 0m
2026-07-23 JJA1107 NRT → ICN Jul 23, 06:45 UTCJul 23, 08:40 UTC1h 55m
2026-07-23 JJA8402 TAO → ICN Jul 23, 04:10 UTCJul 23, 04:30 UTC20m
2026-07-22 JJA8401 ICN → TAO Jul 22, 23:25 UTCJul 22, 23:45 UTC20m
2026-07-22 JJA2396 - Jul 22, 10:20 UTCJul 22, 12:05 UTC1h 45m
2026-07-21 JJA2315 - Jul 21, 10:50 UTCJul 22, 10:20 UTC23h 30m
2026-07-21 JJA2315 - Jul 21, 08:45 UTCJul 21, 11:25 UTC2h 40m
2026-07-21 JJA1176 NRT → ICN Jul 21, 05:25 UTCJul 21, 07:25 UTC2h 0m
2026-07-21 JJA1175 NRT → PUS Jul 21, 01:05 UTCJul 21, 03:00 UTC1h 55m
2026-07-20 JJA1106 NRT → ICN Jul 20, 08:45 UTCJul 20, 10:55 UTC2h 10m
2026-07-20 JJA1105 NRT → ICN Jul 20, 05:15 UTCJul 20, 07:20 UTC2h 5m
2026-07-20 JJA8402 TAO → ICN Jul 20, 03:10 UTCJul 20, 03:30 UTC20m
2026-07-19 JJA8401 ICN → TAO Jul 19, 23:25 UTCJul 20, 00:00 UTC35m
2026-07-19 JJA1108 NRT → ICN Jul 19, 10:00 UTCJul 19, 11:50 UTC1h 50m
2026-07-19 JJA1107 NRT → ICN Jul 19, 06:30 UTCJul 19, 08:35 UTC2h 5m
2026-07-19 JJA1404 FUK → ICN Jul 19, 03:25 UTCJul 19, 04:20 UTC55m
2026-07-19 JJA1403 ICN → FUK Jul 19, 01:00 UTCJul 19, 01:45 UTC45m
2026-07-18 JJA2316 PQC → ICN Jul 18, 09:05 UTCJul 18, 20:50 UTC11h 45m
2026-07-18 JJA1176 NRT → ICN Jul 18, 04:40 UTCJul 18, 06:40 UTC2h 0m
2026-07-18 JJA1175 ICN → NRT Jul 18, 01:05 UTCJul 18, 03:00 UTC1h 56m
2026-07-17 JJA2108 - Jul 17, 17:50 UTCJul 17, 21:50 UTC4h 0m
2026-07-17 JJA2107 - Jul 17, 12:50 UTCJul 17, 16:10 UTC3h 20m
2026-07-17 JJA2212 - Jul 17, 10:10 UTCJul 17, 10:50 UTC40m
2026-07-17 JJA2211 - Jul 17, 00:35 UTCJul 17, 08:59 UTC8h 25m
2026-07-16 JJA2108 - Jul 16, 17:49 UTCJul 16, 21:25 UTC3h 35m
2026-07-16 JJA2107 - Jul 16, 12:55 UTCJul 16, 16:09 UTC3h 15m
2026-07-16 JJA1204 - Jul 16, 09:30 UTCJul 16, 10:55 UTC1h 25m
2026-07-16 JJA1203 - Jul 16, 06:30 UTCJul 16, 07:55 UTC1h 25m
2026-07-16 JJA8502 - Jul 16, 04:25 UTCJul 16, 04:50 UTC25m
2026-07-16 JJA8501 - Jul 16, 01:55 UTCJul 16, 02:15 UTC20m
2026-07-15 JJA2504 - Jul 15, 21:25 UTCJul 16, 00:15 UTC2h 50m
2026-07-15 JJA2504 - Jul 15, 19:05 UTCJul 15, 19:20 UTC15m
2026-07-15 JJA2503 - Jul 15, 16:25 UTCJul 15, 16:45 UTC20m
2026-07-15 JJA2503 - Jul 15, 11:40 UTCJul 15, 14:25 UTC2h 45m
2026-07-15 JJA1802 - Jul 15, 09:10 UTCJul 15, 09:45 UTC35m

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?
Yes. Mode-S 71C523 is currently airborne.
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 JJA1108, JJA1802, JJA1301, JJA1107, JJA1302.