sensors Mode-S transponder

71C240

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

Currently assigned to HL8240 · BOEING 737-800

Hex
71C240
Octal
34341100
Decimal
7,455,296
Country
KR
Tail
HL8240
Type
B738
Broadcasting now · callsign KAL856 · 2,650 ft
Flights observed
2
Distinct callsigns
2
Country
KR
Last broadcast
2d ago

Current position

71C240 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 71C240 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
KAL856 - 1 2026-04-13
KAL418 Korean Air 1 2026-04-12

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-13 KAL856 - Apr 13, 06:50 UTCApr 13, 07:05 UTC15m
2026-04-12 KAL418 GUM → ICN Apr 12, 19:40 UTCApr 12, 20:15 UTC35m

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 HL8240 page for operator, model, and routing details .

Mode-S 71C240 frequently asked

What is Mode-S code 71C240?
71C240 is an ICAO 24-bit transponder address. Allocated to Korea, South. Assigned to HL8240.
Where is Mode-S 71C240 registered?
Mode-S code 71C240 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 71C240 broadcasting right now?
Yes. Mode-S 71C240 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 71C240, octal 34341100, decimal 7,455,296.
What flights does 71C240 operate?
Mode-S 71C240 has broadcast 2 distinct callsigns, including KAL856, KAL418.