Apparatus

Try JFK, AAL1290, BAW, or N225AN.

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 Jul 26, 15:25 UTC
Flights observed
348
Distinct callsigns
20
Country
KR
Last broadcast
Jul 26, 15:25 UTC

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 - 29 2026-07-12
TWB281 - 28 2026-07-12
TWB246 Tway Airlines 24 2026-07-21
TWB245 Tway Airlines 22 2026-07-21
TWB302 Tway Airlines 21 2026-07-21
TWB301 Tway Airlines 21 2026-07-20
TWB206 - 18 2026-07-19
TWB205 Tway Airlines 17 2026-07-19
TWB304 Tway Airlines 15 2026-07-26
TWB303 Tway Airlines 15 2026-07-26
TWB007 - 14 2026-07-21
TWB438 Tway Airlines 11 2026-07-19
TWB202 - 11 2026-06-30
TWB008 - 10 2026-07-10
TWB437 Tway Airlines 9 2026-07-18
TWB201 - 9 2026-06-30
TWB055 Tway Airlines 8 2026-04-28
TWB056 Tway Airlines 7 2026-07-22
TWB034 - 6 2026-07-07
TWB033 - 6 2026-07-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 TWB248 NRT → ICN Jul 26, 13:30 UTCJul 26, 15:20 UTC1h 50m
2026-07-26 TWB247 ICN → NRT Jul 26, 09:35 UTCJul 26, 11:50 UTC2h 15m
2026-07-26 TWB304 KIX → ICN Jul 26, 05:50 UTCJul 26, 07:15 UTC1h 26m
2026-07-26 TWB303 ICN → KIX Jul 26, 02:20 UTCJul 26, 03:40 UTC1h 20m
2026-07-25 TWB102 BKK → ICN Jul 25, 17:35 UTCJul 25, 22:40 UTC5h 5m
2026-07-25 TWB101 ICN → BKK Jul 25, 09:30 UTCJul 25, 14:45 UTC5h 15m
2026-07-25 TWB304 KIX → ICN Jul 25, 06:00 UTCJul 25, 07:20 UTC1h 20m
2026-07-25 TWB303 ICN → KIX Jul 25, 02:20 UTCJul 25, 03:55 UTC1h 35m
2026-07-24 TWB306 KIX → ICN Jul 24, 11:55 UTCJul 24, 13:25 UTC1h 30m
2026-07-24 TWB305 ICN → KIX Jul 24, 08:45 UTCJul 24, 10:05 UTC1h 20m
2026-07-24 TWB304 KIX → ICN Jul 24, 05:55 UTCJul 24, 07:20 UTC1h 25m
2026-07-24 TWB303 ICN → KIX Jul 24, 02:25 UTCJul 24, 03:55 UTC1h 30m
2026-07-23 TWB102 BKK → ICN Jul 23, 17:50 UTCJul 23, 23:00 UTC5h 10m
2026-07-23 TWB101 - Jul 23, 09:25 UTCJul 23, 14:45 UTC5h 20m
2026-07-23 TWB304 KIX → ICN Jul 23, 05:55 UTCJul 23, 07:15 UTC1h 20m
2026-07-23 TWB303 ICN → KIX Jul 23, 02:10 UTCJul 23, 03:30 UTC1h 20m
2026-07-22 TWB056 PQC → ICN Jul 22, 11:10 UTCJul 22, 23:30 UTC12h 20m
2026-07-21 TWB007 - Jul 21, 23:25 UTCJul 22, 02:10 UTC2h 45m
2026-07-21 TWB246 NRT → ICN Jul 21, 10:25 UTCJul 21, 12:25 UTC2h 0m
2026-07-21 TWB245 ICN → NRT Jul 21, 06:20 UTCJul 21, 08:15 UTC1h 55m
2026-07-21 TWB302 KIX → ICN Jul 21, 03:40 UTCJul 21, 05:00 UTC1h 20m
2026-07-20 TWB301 ICN → KIX Jul 20, 23:20 UTCJul 21, 00:50 UTC1h 29m
2026-07-20 TWB248 NRT → ICN Jul 20, 13:15 UTCJul 20, 15:10 UTC1h 55m
2026-07-20 TWB247 ICN → NRT Jul 20, 09:55 UTCJul 20, 11:50 UTC1h 55m
2026-07-20 TWB304 KIX → ICN Jul 20, 05:55 UTCJul 20, 07:15 UTC1h 20m
2026-07-20 TWB303 ICN → KIX Jul 20, 02:45 UTCJul 20, 04:25 UTC1h 40m
2026-07-19 TWB308 KIX → ICN Jul 19, 15:30 UTCJul 19, 16:45 UTC1h 15m
2026-07-19 TWB307 - Jul 19, 12:20 UTCJul 19, 13:40 UTC1h 20m
2026-07-19 TWB206 - Jul 19, 08:45 UTCJul 19, 09:40 UTC55m
2026-07-19 TWB205 ICN → FUK Jul 19, 06:15 UTCJul 19, 07:00 UTC45m
2026-07-19 TWB438 FRU → ICN Jul 19, 00:50 UTCJul 19, 01:05 UTC15m
2026-07-18 TWB438 FRU → ICN Jul 18, 12:40 UTCJul 19, 00:00 UTC11h 20m
2026-07-18 TWB437 ICN → FRU Jul 18, 11:20 UTCJul 18, 11:45 UTC25m
2026-07-17 TWB007 ICN → ICN Jul 17, 23:30 UTCJul 18, 09:15 UTC9h 46m
2026-07-17 TWB308 KIX → ICN Jul 17, 15:25 UTCJul 17, 16:40 UTC1h 15m
2026-07-17 TWB307 - Jul 17, 12:19 UTCJul 17, 14:00 UTC1h 40m
2026-07-17 TWB206 - Jul 17, 08:45 UTCJul 17, 09:45 UTC1h 0m
2026-07-17 TWB205 - Jul 17, 06:29 UTCJul 17, 07:14 UTC45m
2026-07-17 TWB302 - Jul 17, 03:05 UTCJul 17, 04:20 UTC1h 15m
2026-07-16 TWB301 ICN → KIX Jul 16, 23:25 UTCJul 17, 00:50 UTC1h 25m
2026-07-16 TWB033 ICN → ICN Jul 16, 10:50 UTCJul 16, 21:25 UTC10h 35m
2026-07-15 TWB007 - Jul 15, 23:15 UTCJul 16, 09:20 UTC10h 5m
2026-07-15 TWB246 NRT → ICN Jul 15, 10:25 UTCJul 15, 12:25 UTC2h 0m
2026-07-15 TWB245 - Jul 15, 06:35 UTCJul 15, 08:35 UTC2h 0m
2026-07-15 TWB302 KIX → ICN Jul 15, 03:05 UTCJul 15, 04:20 UTC1h 15m
2026-07-14 TWB301 - Jul 14, 23:30 UTCJul 15, 00:50 UTC1h 20m
2026-07-14 TWB246 - Jul 14, 10:25 UTCJul 14, 12:25 UTC2h 0m
2026-07-14 TWB245 ICN → NRT Jul 14, 06:15 UTCJul 14, 08:10 UTC1h 55m
2026-07-14 TWB302 KIX → ICN Jul 14, 02:40 UTCJul 14, 04:05 UTC1h 25m
2026-07-13 TWB301 ICN → KIX Jul 13, 23:10 UTCJul 14, 00:35 UTC1h 25m

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 Jul 26, 15:25 UTC.
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, TWB302.