Apparatus

Try JFK, AAL1290, BAW, or N225AN.

sensors Mode-S transponder

71C556

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

Currently assigned to HL8556 · AIRBUS A-321neo

Hex
71C556
Octal
34342526
Decimal
7,456,086
Country
KR
Tail
HL8556
Type
A21N
No current signal · last broadcast Jul 23, 15:25 UTC
Flights observed
334
Distinct callsigns
20
Country
KR
Last broadcast
Jul 23, 15:25 UTC

Last known position

Most recent position reported by Mode-S 71C556.

Country allocation

The ICAO 24-bit address 71C556 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
KAL743 - 11 2026-07-07
KAL2173 Korean Air 10 2026-07-19
KAL712 - 9 2026-07-08
KAL625 - 9 2026-07-09
KAL2174 - 9 2026-07-19
KAL626 - 8 2026-07-09
KAL2172 Korean Air 8 2026-07-19
KAL2171 Korean Air 8 2026-07-19
KAL2005 - 8 2026-07-17
KAL791 - 7 2026-07-05
KAL744 - 7 2026-07-08
KAL726 - 7 2026-07-01
KAL725 - 7 2026-07-01
KAL711 - 7 2026-07-08
KAL655 - 7 2026-07-08
KAL2016 - 7 2026-07-15
KAL852 - 6 2026-06-28
KAL792 - 6 2026-07-05
KAL708 - 6 2026-05-26
KAL656 - 6 2026-07-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-23 KAL299F - Jul 23, 12:25 UTCJul 23, 15:25 UTC3h 0m
2026-07-22 KAL772 CTS → PUS Jul 22, 12:10 UTCJul 22, 14:40 UTC2h 30m
2026-07-21 KAL486 PQC → ICN Jul 21, 10:30 UTCJul 21, 23:05 UTC12h 35m
2026-07-20 KAL458 DAD → ICN Jul 20, 03:10 UTCJul 20, 13:30 UTC10h 20m
2026-07-19 KAL2174 UKB → ICN Jul 19, 10:15 UTCJul 19, 11:30 UTC1h 15m
2026-07-19 KAL2173 ICN → UKB Jul 19, 07:15 UTCJul 19, 08:45 UTC1h 30m
2026-07-19 KAL2172 UKB → ICN Jul 19, 03:15 UTCJul 19, 04:30 UTC1h 15m
2026-07-19 KAL2171 ICN → UKB Jul 19, 00:25 UTCJul 19, 01:40 UTC1h 15m
2026-07-18 KAL2174 UKB → ICN Jul 18, 10:05 UTCJul 18, 11:20 UTC1h 15m
2026-07-18 KAL2173 ICN → UKB Jul 18, 07:15 UTCJul 18, 08:35 UTC1h 20m
2026-07-18 KAL2172 UKB → ICN Jul 18, 03:15 UTCJul 18, 04:35 UTC1h 20m
2026-07-18 KAL2171 ICN → UKB Jul 18, 00:25 UTCJul 18, 01:45 UTC1h 20m
2026-07-17 KAL2006 - Jul 17, 12:45 UTCJul 17, 13:29 UTC45m
2026-07-17 KAL2006 - Jul 17, 10:15 UTCJul 17, 11:39 UTC1h 25m
2026-07-17 KAL2005 ICN → HKG Jul 17, 04:54 UTCJul 17, 08:00 UTC3h 5m
2026-07-17 KAL1408 PUS → ICN Jul 17, 01:49 UTCJul 17, 02:25 UTC35m
2026-07-16 KAL1403 ICN → PUS Jul 16, 23:29 UTCJul 17, 00:14 UTC45m
2026-07-16 KAL2174 UKB → ICN Jul 16, 10:04 UTCJul 16, 11:30 UTC1h 25m
2026-07-16 KAL2173 ICN → UKB Jul 16, 07:10 UTCJul 16, 08:30 UTC1h 20m
2026-07-16 KAL2172 UKB → ICN Jul 16, 03:35 UTCJul 16, 04:55 UTC1h 20m
2026-07-16 KAL2171 ICN → UKB Jul 16, 00:45 UTCJul 16, 02:05 UTC1h 20m
2026-07-15 KAL738 KIX → ICN Jul 15, 17:40 UTCJul 15, 19:00 UTC1h 20m
2026-07-15 KAL737 ICN → KIX Jul 15, 12:10 UTCJul 15, 13:35 UTC1h 25m
2026-07-15 KAL2016 - Jul 15, 07:05 UTCJul 15, 10:25 UTC3h 20m
2026-07-15 KAL2015 - Jul 15, 01:25 UTCJul 15, 04:35 UTC3h 10m
2026-07-14 KAL2174 UKB → ICN Jul 14, 10:00 UTCJul 14, 11:25 UTC1h 25m
2026-07-14 KAL2173 ICN → UKB Jul 14, 07:05 UTCJul 14, 08:20 UTC1h 15m
2026-07-14 KAL2172 UKB → ICN Jul 14, 03:05 UTCJul 14, 04:25 UTC1h 20m
2026-07-14 KAL2171 ICN → UKB Jul 14, 00:20 UTCJul 14, 01:40 UTC1h 20m
2026-07-13 KAL458 - Jul 13, 04:40 UTCJul 13, 13:30 UTC8h 50m
2026-07-13 KAL457 - Jul 13, 03:05 UTCJul 13, 03:40 UTC35m
2026-07-12 KAL2174 UKB → ICN Jul 12, 10:05 UTCJul 12, 11:25 UTC1h 20m
2026-07-12 KAL2173 ICN → UKB Jul 12, 07:10 UTCJul 12, 08:25 UTC1h 15m
2026-07-12 KAL2172 UKB → ICN Jul 12, 03:10 UTCJul 12, 04:45 UTC1h 35m
2026-07-12 KAL2171 ICN → UKB Jul 12, 00:25 UTCJul 12, 01:50 UTC1h 25m
2026-07-11 KAL2174 UKB → ICN Jul 11, 09:55 UTCJul 11, 11:15 UTC1h 20m
2026-07-11 KAL2173 ICN → UKB Jul 11, 07:15 UTCJul 11, 08:30 UTC1h 15m
2026-07-11 KAL2172 UKB → ICN Jul 11, 03:05 UTCJul 11, 04:20 UTC1h 15m
2026-07-11 KAL2171 ICN → UKB Jul 11, 00:15 UTCJul 11, 01:35 UTC1h 20m
2026-07-10 KAL2174 UKB → ICN Jul 10, 10:00 UTCJul 10, 11:25 UTC1h 25m
2026-07-10 KAL2173 - Jul 10, 07:05 UTCJul 10, 08:25 UTC1h 20m
2026-07-10 KAL2172 UKB → ICN Jul 10, 03:10 UTCJul 10, 04:40 UTC1h 30m
2026-07-10 KAL2171 ICN → UKB Jul 10, 00:30 UTCJul 10, 01:50 UTC1h 20m
2026-07-09 KAL626 - Jul 9, 17:30 UTCJul 9, 21:10 UTC3h 40m
2026-07-09 KAL625 - Jul 9, 12:05 UTCJul 9, 15:35 UTC3h 30m
2026-07-08 KAL656 - Jul 8, 19:55 UTCJul 9, 01:15 UTC5h 20m
2026-07-08 KAL655 - Jul 8, 13:20 UTCJul 8, 17:50 UTC4h 30m
2026-07-08 KAL655 - Jul 8, 12:45 UTCJul 8, 13:15 UTC30m
2026-07-08 KAL712 - Jul 8, 08:30 UTCJul 8, 10:30 UTC2h 0m
2026-07-08 KAL711 ICN → NRT Jul 8, 04:15 UTCJul 8, 06:15 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 HL8556 page for operator, model, and routing details .

Mode-S 71C556 frequently asked

What is Mode-S code 71C556?
71C556 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8556.
Where is Mode-S 71C556 registered?
Mode-S code 71C556 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 71C556 broadcasting right now?
No active broadcast right now. Last signal was Jul 23, 15:25 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C556, octal 34342526, decimal 7,456,086.
What flights does 71C556 operate?
Mode-S 71C556 has broadcast 20 distinct callsigns, including KAL743, KAL2173, KAL712, KAL625, KAL2174.