Apparatus

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sensors Mode-S transponder

71C557

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

Currently assigned to HL8557 · AIRBUS A-321neo

Hex
71C557
Octal
34342527
Decimal
7,456,087
Country
KR
Tail
HL8557
Type
A21N
Transponder active on ground
Flights observed
485
Distinct callsigns
20
Country
KR
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 71C557.

Country allocation

The ICAO 24-bit address 71C557 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
KAL1045 - 59 2026-07-13
KAL1174 - 58 2026-07-14
KAL1822 - 57 2026-07-14
KAL1819 - 56 2026-07-14
KAL1827 - 33 2026-07-14
KAL1830 - 31 2026-07-13
KAL1328 Korean Air 23 2026-06-10
KAL1205 Korean Air 23 2026-06-10
KAL706 Korean Air 6 2026-04-20
KAL2147 Korean Air 6 2026-05-03
KAL2016 Korean Air 6 2026-05-10
KAL2005 Korean Air 6 2026-04-25
KAL792 Korean Air 5 2026-05-15
KAL705 Korean Air 5 2026-04-19
KAL689 Korean Air 5 2026-04-29
KAL2180 Korean Air 5 2026-05-13
KAL2172 Korean Air 5 2026-05-06
KAL2148 Korean Air 5 2026-05-12
KAL2015 Korean Air 5 2026-05-10
KAL2006 Korean Air 5 2026-04-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 KAL1827 - Jul 14, 09:15 UTCJul 14, 09:45 UTC30m
2026-07-14 KAL1822 PUS → GMP Jul 14, 07:15 UTCJul 14, 08:05 UTC50m
2026-07-14 KAL1819 GMP → PUS Jul 14, 05:25 UTCJul 14, 06:10 UTC45m
2026-07-14 KAL1174 - Jul 14, 02:00 UTCJul 14, 02:45 UTC45m
2026-07-13 KAL1045 - Jul 13, 23:30 UTCJul 14, 00:05 UTC35m
2026-07-13 KAL1830 PUS → GMP Jul 13, 10:50 UTCJul 13, 11:35 UTC45m
2026-07-13 KAL1827 GMP → PUS Jul 13, 09:05 UTCJul 13, 09:45 UTC40m
2026-07-13 KAL1822 PUS → GMP Jul 13, 07:10 UTCJul 13, 07:55 UTC45m
2026-07-13 KAL1819 GMP → PUS Jul 13, 05:20 UTCJul 13, 06:01 UTC40m
2026-07-13 KAL1174 - Jul 13, 02:25 UTCJul 13, 03:05 UTC40m
2026-07-12 KAL1045 - Jul 12, 23:40 UTCJul 13, 00:15 UTC35m
2026-07-12 KAL1830 PUS → GMP Jul 12, 10:40 UTCJul 12, 11:15 UTC35m
2026-07-12 KAL1827 GMP → PUS Jul 12, 08:55 UTCJul 12, 09:40 UTC45m
2026-07-12 KAL1822 PUS → GMP Jul 12, 07:10 UTCJul 12, 07:55 UTC45m
2026-07-12 KAL1819 GMP → PUS Jul 12, 05:25 UTCJul 12, 06:05 UTC40m
2026-07-12 KAL1174 - Jul 12, 03:15 UTCJul 12, 04:01 UTC46m
2026-07-12 KAL1045 - Jul 12, 01:00 UTCJul 12, 01:35 UTC35m
2026-07-11 KAL1830 PUS → GMP Jul 11, 10:40 UTCJul 11, 11:15 UTC35m
2026-07-11 KAL1827 GMP → PUS Jul 11, 08:55 UTCJul 11, 09:35 UTC40m
2026-07-11 KAL1822 PUS → GMP Jul 11, 07:10 UTCJul 11, 07:50 UTC40m
2026-07-11 KAL1819 GMP → PUS Jul 11, 05:15 UTCJul 11, 05:55 UTC40m
2026-07-11 KAL1174 - Jul 11, 01:55 UTCJul 11, 02:35 UTC40m
2026-07-10 KAL1045 - Jul 10, 23:35 UTCJul 11, 00:10 UTC35m
2026-07-10 KAL1830 PUS → GMP Jul 10, 10:50 UTCJul 10, 11:35 UTC45m
2026-07-10 KAL1827 GMP → PUS Jul 10, 09:10 UTCJul 10, 09:50 UTC40m
2026-07-10 KAL1822 PUS → GMP Jul 10, 07:15 UTCJul 10, 08:05 UTC50m
2026-07-10 KAL1819 GMP → PUS Jul 10, 05:20 UTCJul 10, 06:05 UTC45m
2026-07-10 KAL1174 - Jul 10, 01:50 UTCJul 10, 02:35 UTC45m
2026-07-09 KAL1045 - Jul 9, 23:35 UTCJul 10, 00:10 UTC35m
2026-07-09 KAL1830 PUS → GMP Jul 9, 10:35 UTCJul 9, 11:20 UTC45m
2026-07-09 KAL1827 GMP → PUS Jul 9, 08:55 UTCJul 9, 09:35 UTC40m
2026-07-09 KAL1822 PUS → GMP Jul 9, 07:15 UTCJul 9, 08:00 UTC45m
2026-07-09 KAL1819 GMP → PUS Jul 9, 05:20 UTCJul 9, 06:10 UTC50m
2026-07-09 KAL1174 - Jul 9, 02:20 UTCJul 9, 03:05 UTC45m
2026-07-08 KAL1045 - Jul 8, 23:55 UTCJul 9, 00:45 UTC50m
2026-07-08 KAL1830 PUS → GMP Jul 8, 10:45 UTCJul 8, 11:30 UTC45m
2026-07-08 KAL1827 GMP → PUS Jul 8, 09:10 UTCJul 8, 09:50 UTC40m
2026-07-08 KAL1822 PUS → GMP Jul 8, 07:15 UTCJul 8, 08:00 UTC45m
2026-07-08 KAL1819 GMP → PUS Jul 8, 05:25 UTCJul 8, 06:15 UTC50m
2026-07-08 KAL1174 - Jul 8, 01:55 UTCJul 8, 02:35 UTC40m
2026-07-07 KAL1045 - Jul 7, 23:40 UTCJul 8, 00:15 UTC35m
2026-07-07 KAL1830 PUS → GMP Jul 7, 10:45 UTCJul 7, 11:20 UTC35m
2026-07-07 KAL1827 GMP → PUS Jul 7, 08:55 UTCJul 7, 09:35 UTC40m
2026-07-07 KAL1822 PUS → GMP Jul 7, 07:10 UTCJul 7, 07:50 UTC40m
2026-07-07 KAL1819 GMP → PUS Jul 7, 05:15 UTCJul 7, 05:55 UTC40m
2026-07-07 KAL1174 - Jul 7, 02:00 UTCJul 7, 02:40 UTC40m
2026-07-06 KAL1045 - Jul 6, 23:45 UTCJul 7, 00:20 UTC35m
2026-07-06 KAL1830 PUS → GMP Jul 6, 10:35 UTCJul 6, 11:15 UTC40m
2026-07-06 KAL1827 GMP → PUS Jul 6, 08:55 UTCJul 6, 09:35 UTC40m
2026-07-06 KAL1822 PUS → GMP Jul 6, 07:05 UTCJul 6, 07:55 UTC50m

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 HL8557 page for operator, model, and routing details .

Mode-S 71C557 frequently asked

What is Mode-S code 71C557?
71C557 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8557.
Where is Mode-S 71C557 registered?
Mode-S code 71C557 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 71C557 broadcasting right now?
Mode-S 71C557 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 71C557, octal 34342527, decimal 7,456,087.
What flights does 71C557 operate?
Mode-S 71C557 has broadcast 20 distinct callsigns, including KAL1045, KAL1174, KAL1822, KAL1819, KAL1827.