sensors Mode-S transponder

501C1C

ICAO 24-bit transponder address · allocated to Croatia

Currently assigned to 9A-BTK · AIRBUS A-320

Hex
501C1C
Octal
24016034
Decimal
5,250,076
Country
HR
Tail
9A-BTK
Type
A320
No current signal · last broadcast 13h ago
Flights observed
1
Distinct callsigns
1
Country
HR
Last broadcast
13h ago

Last known position

Most recent position reported by Mode-S 501C1C.

Country allocation

The ICAO 24-bit address 501C1C falls within the block assigned to Croatia (HR) by ICAO Annex 10, Volume III. Every aircraft registered in Croatia 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 1 distinct

Callsign Airline Flights Last seen
TDR203 Trade Air 1 2026-04-18

Recent flights last 1

DateFlightRouteTakeoffLandingDuration
2026-04-18 TDR203 TER → LJU Apr 18, 13:35 UTCApr 18, 16:30 UTC2h 55m

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 9A-BTK page for operator, model, and routing details .

Mode-S 501C1C frequently asked

What is Mode-S code 501C1C?
501C1C is an ICAO 24-bit transponder address. Allocated to Croatia. Assigned to 9A-BTK.
Where is Mode-S 501C1C registered?
Mode-S code 501C1C is allocated to Croatia (HR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 501C1C broadcasting right now?
No active broadcast right now. Last signal was 13h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 501C1C, octal 24016034, decimal 5,250,076.
What flights does 501C1C operate?
Mode-S 501C1C has broadcast 1 distinct callsign, including TDR203.