sensors Mode-S transponder

71C546

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

Currently assigned to HL8546 · BOEING 737-800

Hex
71C546
Octal
34342506
Decimal
7,456,070
Country
KR
Tail
HL8546
Type
B738
No current signal · last broadcast 1d ago
Flights observed
11
Distinct callsigns
9
Country
KR
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 71C546.

Country allocation

The ICAO 24-bit address 71C546 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 9 distinct

Callsign Airline Flights Last seen
ESR284 - 2 2026-04-13
ESR230 - 2 2026-04-13
ESR988 - 1 2026-04-12
ESR283 - 1 2026-04-13
ESR219 - 1 2026-04-13
ESR212 - 1 2026-04-13
ESR211 - 1 2026-04-13
ESR206 Eastar Jet 1 2026-04-13
ESR205 Eastar Jet 1 2026-04-13

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-13 ESR205 GMP → CJU Apr 13, 22:00 UTCApr 13, 22:35 UTC35m
2026-04-13 ESR230 - Apr 13, 12:20 UTCApr 13, 12:45 UTC25m
2026-04-13 ESR230 - Apr 13, 12:05 UTCApr 13, 12:15 UTC10m
2026-04-13 ESR283 - Apr 13, 09:50 UTCApr 13, 10:25 UTC35m
2026-04-13 ESR284 - Apr 13, 08:20 UTCApr 13, 08:45 UTC25m
2026-04-13 ESR284 - Apr 13, 08:10 UTCApr 13, 08:45 UTC35m
2026-04-13 ESR219 - Apr 13, 06:05 UTCApr 13, 06:40 UTC35m
2026-04-13 ESR212 - Apr 13, 04:20 UTCApr 13, 04:55 UTC35m
2026-04-13 ESR211 - Apr 13, 02:10 UTCApr 13, 02:45 UTC35m
2026-04-13 ESR206 CJU → GMP Apr 13, 00:30 UTCApr 13, 01:05 UTC35m
2026-04-12 ESR988 - Apr 12, 18:55 UTCApr 12, 19:10 UTC15m

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 HL8546 page for operator, model, and routing details .

Mode-S 71C546 frequently asked

What is Mode-S code 71C546?
71C546 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8546.
Where is Mode-S 71C546 registered?
Mode-S code 71C546 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 71C546 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C546, octal 34342506, decimal 7,456,070.
What flights does 71C546 operate?
Mode-S 71C546 has broadcast 9 distinct callsigns, including ESR284, ESR230, ESR988, ESR283, ESR219.