Apparatus

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sensors Mode-S transponder

71C581

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

Currently assigned to HL8581 · BOEING 737 MAX 8

Hex
71C581
Octal
34342601
Decimal
7,456,129
Country
KR
Tail
HL8581
Type
B38M
No current signal · last broadcast 1h ago
Flights observed
161
Distinct callsigns
20
Country
KR
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 71C581.

Country allocation

The ICAO 24-bit address 71C581 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
TWB282 Tway Airlines 22 2026-05-29
TWB281 Tway Airlines 19 2026-05-25
TWB246 Tway Airlines 10 2026-05-19
TWB245 Tway Airlines 9 2026-05-19
TWB206 Tway Airlines 8 2026-05-24
TWB055 Tway Airlines 8 2026-04-28
TWB008 - 7 2026-05-20
TWB302 Tway Airlines 6 2026-05-23
TWB301 Tway Airlines 6 2026-05-22
TWB205 Tway Airlines 6 2026-05-24
TWB056 Tway Airlines 6 2026-04-27
TWB007 - 6 2026-05-15
TWB438 Tway Airlines 4 2026-05-28
TWB241 Tway Airlines 4 2026-05-10
TWB202 Tway Airlines 4 2026-04-29
TWB033 Tway Airlines 4 2026-04-18
TWB437 Tway Airlines 3 2026-05-28
TWB303 Tway Airlines 3 2026-05-30
TWB242 Tway Airlines 3 2026-05-11
TWB201 Tway Airlines 3 2026-04-29

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 TWB303 ICN → KIX May 30, 02:06 UTCMay 30, 03:25 UTC1h 19m
2026-05-29 TWB282 OKA → ICN May 29, 02:25 UTCMay 29, 07:35 UTC5h 10m
2026-05-28 TWB438 FRU → ICN May 28, 23:50 UTCMay 29, 00:15 UTC25m
2026-05-28 TWB438 FRU → ICN May 28, 11:30 UTCMay 28, 23:05 UTC11h 35m
2026-05-28 TWB437 ICN → FRU May 28, 10:05 UTCMay 28, 10:20 UTC15m
2026-05-28 TWB282 OKA → ICN May 28, 02:15 UTCMay 28, 08:10 UTC5h 55m
2026-05-27 TWB102 BKK → ICN May 27, 17:35 UTCMay 27, 22:45 UTC5h 10m
2026-05-27 TWB101 ICN → BKK May 27, 09:30 UTCMay 27, 14:35 UTC5h 5m
2026-05-27 TWB282 OKA → ICN May 27, 02:24 UTCMay 27, 07:35 UTC5h 10m
2026-05-27 TWB438 FRU → ICN May 27, 00:00 UTCMay 27, 00:19 UTC20m
2026-05-26 TWB437 ICN → FRU May 26, 10:05 UTCMay 26, 23:14 UTC13h 10m
2026-05-26 TWB282 OKA → ICN May 26, 02:15 UTCMay 26, 08:10 UTC5h 55m
2026-05-25 TWB281 ICN → OKA May 25, 02:20 UTCMay 25, 08:10 UTC5h 50m
2026-05-24 TWB206 FUK → ICN May 24, 09:30 UTCMay 24, 10:20 UTC50m
2026-05-24 TWB205 ICN → FUK May 24, 07:30 UTCMay 24, 08:00 UTC30m
2026-05-23 TWB206 FUK → ICN May 23, 08:35 UTCMay 23, 09:35 UTC1h 0m
2026-05-23 TWB205 ICN → FUK May 23, 06:10 UTCMay 23, 06:40 UTC30m
2026-05-23 TWB302 KIX → ICN May 23, 02:50 UTCMay 23, 04:15 UTC1h 25m
2026-05-22 TWB301 ICN → KIX May 22, 23:10 UTCMay 23, 00:35 UTC1h 25m
2026-05-22 TWB304 KIX → ICN May 22, 05:45 UTCMay 22, 07:20 UTC1h 35m
2026-05-22 TWB303 ICN → KIX May 22, 02:10 UTCMay 22, 03:40 UTC1h 30m
2026-05-20 TWB008 ICN → ICN May 20, 23:25 UTCMay 21, 09:10 UTC9h 45m
2026-05-20 TWB206 FUK → ICN May 20, 08:40 UTCMay 20, 09:50 UTC1h 10m
2026-05-20 TWB205 ICN → FUK May 20, 06:15 UTCMay 20, 06:45 UTC30m
2026-05-20 TWB302 KIX → ICN May 20, 03:00 UTCMay 20, 04:30 UTC1h 30m
2026-05-19 TWB301 ICN → KIX May 19, 23:20 UTCMay 20, 00:40 UTC1h 20m
2026-05-19 TWB246 NRT → ICN May 19, 10:15 UTCMay 19, 12:15 UTC2h 0m
2026-05-19 TWB245 ICN → NRT May 19, 06:10 UTCMay 19, 08:10 UTC2h 0m
2026-05-18 TWB282 OKA → ICN May 18, 07:15 UTCMay 18, 07:50 UTC35m
2026-05-18 TWB282 OKA → ICN May 18, 06:01 UTCMay 18, 06:10 UTC10m
2026-05-18 TWB281 ICN → OKA May 18, 03:40 UTCMay 18, 04:00 UTC20m
2026-05-18 TWB281 ICN → OKA May 18, 02:20 UTCMay 18, 02:45 UTC25m
2026-05-17 TWB304 KIX → ICN May 17, 05:50 UTCMay 17, 07:05 UTC1h 15m
2026-05-17 TWB303 ICN → KIX May 17, 02:15 UTCMay 17, 03:40 UTC1h 25m
2026-05-15 TWB007 ICN → ICN May 15, 23:20 UTCMay 16, 09:21 UTC10h 1m
2026-05-15 TWB282 OKA → ICN May 15, 05:40 UTCMay 15, 07:25 UTC1h 45m
2026-05-15 TWB281 ICN → OKA May 15, 02:20 UTCMay 15, 04:00 UTC1h 40m
2026-05-14 TWB438 FRU → ICN May 14, 23:45 UTCMay 15, 00:05 UTC20m
2026-05-14 TWB437 ICN → FRU May 14, 10:10 UTCMay 14, 10:25 UTC15m
2026-05-14 TWB282 OKA → ICN May 14, 06:10 UTCMay 14, 08:05 UTC1h 55m
2026-05-14 TWB281 ICN → OKA May 14, 03:35 UTCMay 14, 04:00 UTC25m
2026-05-14 TWB281 ICN → OKA May 14, 02:20 UTCMay 14, 02:50 UTC30m
2026-05-12 TWB008 - May 12, 23:15 UTCMay 13, 09:05 UTC9h 50m
2026-05-12 TWB034 CXR → ICN May 12, 11:10 UTCMay 12, 21:35 UTC10h 25m
2026-05-12 TWB282 OKA → ICN May 12, 05:50 UTCMay 12, 07:35 UTC1h 45m
2026-05-12 TWB281 ICN → OKA May 12, 03:40 UTCMay 12, 04:05 UTC25m
2026-05-12 TWB281 ICN → OKA May 12, 02:45 UTCMay 12, 03:00 UTC15m
2026-05-11 TWB242 NRT → ICN May 11, 03:30 UTCMay 11, 05:35 UTC2h 5m
2026-05-10 TWB241 ICN → NRT May 10, 23:50 UTCMay 11, 01:45 UTC1h 55m
2026-05-10 TWB354 - May 10, 10:49 UTCMay 10, 12:19 UTC1h 30m

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 HL8581 page for operator, model, and routing details .

Mode-S 71C581 frequently asked

What is Mode-S code 71C581?
71C581 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8581.
Where is Mode-S 71C581 registered?
Mode-S code 71C581 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 71C581 broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C581, octal 34342601, decimal 7,456,129.
What flights does 71C581 operate?
Mode-S 71C581 has broadcast 20 distinct callsigns, including TWB282, TWB281, TWB246, TWB245, TWB206.