sensors Mode-S transponder

71F2E4

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

Hex
71F2E4
Octal
34371344
Decimal
7,467,748
Country
KR
No current signal · last broadcast 3d ago
Flights observed
2
Distinct callsigns
2
Country
KR
Last broadcast
3d ago

Last known position

Most recent position reported by Mode-S 71F2E4.

Country allocation

The ICAO 24-bit address 71F2E4 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 2 distinct

Callsign Airline Flights Last seen
CU31 - 1 2026-06-28
CU22 - 1 2026-06-29

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-06-29 CU22 PUS → PUS Jun 29, 04:55 UTCJun 29, 06:44 UTC1h 50m
2026-06-28 CU31 PUS → PUS Jun 28, 23:44 UTCJun 29, 01:50 UTC2h 5m

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.

Mode-S 71F2E4 frequently asked

What is Mode-S code 71F2E4?
71F2E4 is an ICAO 24-bit transponder address. Allocated to Korea, South.
Where is Mode-S 71F2E4 registered?
Mode-S code 71F2E4 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 71F2E4 broadcasting right now?
No active broadcast right now. Last signal was 3d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71F2E4, octal 34371344, decimal 7,467,748.
What flights does 71F2E4 operate?
Mode-S 71F2E4 has broadcast 2 distinct callsigns, including CU31, CU22.