Apparatus

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sensors Mode-S transponder

71C251

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

Currently assigned to HL8251 · BOEING 777-200LR

Hex
71C251
Octal
34341121
Decimal
7,455,313
Country
KR
Tail
HL8251
Type
B77L
Broadcasting now · callsign KAL8518 · 35,000 ft
Flights observed
280
Distinct callsigns
20
Country
KR
Last broadcast
Jul 26, 18:10 UTC

Current position

71C251 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 71C251 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
KAL504 Korean Air 14 2026-04-26
KAL349 - 13 2026-07-25
KAL313 - 12 2026-07-22
KAL274 - 11 2026-07-13
KAL9575 Korean Air 9 2026-05-27
KAL320 Korean Air 9 2026-07-24
KAL319 Korean Air 9 2026-07-26
KAL273 - 9 2026-07-12
KAL251 - 9 2026-06-19
KAL503 Korean Air 8 2026-04-25
KAL278 Korean Air 8 2026-07-09
KAL277 - 8 2026-07-09
KAL249 Korean Air 8 2026-07-20
KAL314 - 7 2026-07-22
KAL282 - 7 2026-04-14
KAL9576 Korean Air 6 2026-05-28
KAL8313 - 6 2026-07-17
KAL542 - 6 2026-07-07
KAL541 - 6 2026-07-07
KAL350 - 5 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 KAL319 ICN → CAN Jul 26, 18:00 UTCJul 26, 18:10 UTC10m
2026-07-26 KAL319 ICN → CAN Jul 26, 15:05 UTCJul 26, 17:30 UTC2h 25m
2026-07-26 KAL350 - Jul 26, 06:25 UTCJul 26, 09:15 UTC2h 51m
2026-07-26 KAL350 - Jul 26, 03:30 UTCJul 26, 03:40 UTC10m
2026-07-25 KAL349 - Jul 25, 22:45 UTCJul 26, 00:40 UTC1h 55m
2026-07-25 KAL349 - Jul 25, 20:25 UTCJul 25, 20:40 UTC15m
2026-07-25 KAL349 - Jul 25, 14:20 UTCJul 25, 19:00 UTC4h 40m
2026-07-24 KAL320 CAN → ICN Jul 24, 23:05 UTCJul 24, 23:45 UTC40m
2026-07-24 KAL319 ICN → CAN Jul 24, 15:30 UTCJul 24, 16:10 UTC40m
2026-07-24 KAL554 KIX → ICN Jul 24, 09:40 UTCJul 24, 11:00 UTC1h 20m
2026-07-24 KAL553 ICN → KIX Jul 24, 06:05 UTCJul 24, 07:30 UTC1h 25m
2026-07-23 KAL320 CAN → ICN Jul 23, 23:35 UTCJul 24, 00:15 UTC40m
2026-07-23 KAL319 ICN → CAN Jul 23, 18:20 UTCJul 23, 18:35 UTC15m
2026-07-23 KAL319 ICN → CAN Jul 23, 15:45 UTCJul 23, 16:25 UTC40m
2026-07-23 KAL318 ICN → ICN Jul 23, 03:45 UTCJul 23, 09:20 UTC5h 35m
2026-07-22 KAL314 HKG → ICN Jul 22, 19:20 UTCJul 22, 22:20 UTC3h 0m
2026-07-22 KAL313 - Jul 22, 14:00 UTCJul 22, 16:55 UTC2h 55m
2026-07-21 KAL341 PEN → SGN Jul 21, 21:55 UTCJul 21, 22:10 UTC15m
2026-07-21 KAL341 PEN → SGN Jul 21, 16:40 UTCJul 21, 19:15 UTC2h 35m
2026-07-20 KAL250 JFK → ICN Jul 20, 17:35 UTCJul 21, 08:15 UTC14h 40m
2026-07-20 KAL249 PVG → ANC Jul 20, 07:55 UTCJul 20, 14:10 UTC6h 15m
2026-07-19 KAL249 PVG → ANC Jul 19, 17:25 UTCJul 20, 06:25 UTC13h 0m
2026-07-19 KAL350 - Jul 19, 05:50 UTCJul 19, 08:35 UTC2h 45m
2026-07-18 KAL349 - Jul 18, 22:30 UTCJul 19, 00:10 UTC1h 40m
2026-07-18 KAL349 - Jul 18, 20:00 UTCJul 18, 20:20 UTC20m
2026-07-18 KAL349 - Jul 18, 15:05 UTCJul 18, 18:35 UTC3h 30m
2026-07-18 KAL349 - Jul 18, 13:45 UTCJul 18, 14:25 UTC40m
2026-07-17 KAL320 - Jul 17, 23:05 UTCJul 17, 23:39 UTC35m
2026-07-17 KAL319 - Jul 17, 15:20 UTCJul 17, 16:00 UTC40m
2026-07-17 KAL8314 - Jul 17, 10:10 UTCJul 17, 11:00 UTC50m
2026-07-17 KAL8314 - Jul 17, 07:40 UTCJul 17, 08:59 UTC1h 20m
2026-07-17 KAL8313 - Jul 17, 05:20 UTCJul 17, 05:30 UTC10m
2026-07-17 KAL8313 - Jul 17, 04:04 UTCJul 17, 04:49 UTC45m
2026-07-17 KAL8313 - Jul 17, 02:30 UTCJul 17, 03:05 UTC35m
2026-07-16 KAL320 - Jul 16, 15:14 UTCJul 16, 23:44 UTC8h 30m
2026-07-16 KAL554 KIX → ICN Jul 16, 10:00 UTCJul 16, 11:20 UTC1h 20m
2026-07-16 KAL553 - Jul 16, 05:50 UTCJul 16, 07:15 UTC1h 25m
2026-07-15 KAL320 - Jul 15, 23:05 UTCJul 15, 23:50 UTC45m
2026-07-15 KAL319 - Jul 15, 15:15 UTCJul 15, 15:55 UTC40m
2026-07-14 KAL320 - Jul 14, 23:20 UTCJul 14, 23:55 UTC35m
2026-07-14 KAL319 - Jul 14, 15:40 UTCJul 14, 16:20 UTC40m
2026-07-13 KAL274 - Jul 13, 22:45 UTCJul 14, 10:40 UTC11h 55m
2026-07-13 KAL274 - Jul 13, 12:25 UTCJul 13, 19:45 UTC7h 20m
2026-07-13 KAL274 - Jul 13, 06:50 UTCJul 13, 07:01 UTC10m
2026-07-12 KAL274 - Jul 12, 23:50 UTCJul 13, 02:40 UTC2h 50m
2026-07-12 KAL273 - Jul 12, 14:05 UTCJul 12, 21:40 UTC7h 35m
2026-07-12 KAL273 - Jul 12, 04:25 UTCJul 12, 11:50 UTC7h 25m
2026-07-11 KAL273 - Jul 11, 19:15 UTCJul 12, 03:05 UTC7h 50m
2026-07-11 KAL8204 - Jul 11, 03:15 UTCJul 11, 15:15 UTC12h 0m
2026-07-10 KAL8203 - Jul 10, 13:35 UTCJul 11, 00:25 UTC10h 51m

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 HL8251 page for operator, model, and routing details .

Mode-S 71C251 frequently asked

What is Mode-S code 71C251?
71C251 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8251.
Where is Mode-S 71C251 registered?
Mode-S code 71C251 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 71C251 broadcasting right now?
Yes. Mode-S 71C251 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C251, octal 34341121, decimal 7,455,313.
What flights does 71C251 operate?
Mode-S 71C251 has broadcast 20 distinct callsigns, including KAL504, KAL349, KAL313, KAL274, KAL9575.