sensors Mode-S transponder

501C3B

ICAO 24-bit transponder address · allocated to Croatia

Currently assigned to 9A-CAI · AIRBUS A220-100

Hex
501C3B
Octal
24016073
Decimal
5,250,107
Country
HR
Tail
9A-CAI
Type
BCS1
No current signal · last broadcast 14h ago
Flights observed
10
Distinct callsigns
8
Country
HR
Last broadcast
14h ago

Last known position

Most recent position reported by Mode-S 501C3B.

Country allocation

The ICAO 24-bit address 501C3B 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 8 distinct

Callsign Airline Flights Last seen
CTN486 Croatia Airlines 3 2026-04-13
CTN82W - 1 2026-04-13
CTN82R - 1 2026-04-13
CTN724D - 1 2026-04-12
CTN56E - 1 2026-04-14
CTN487 - 1 2026-04-13
CTN456 Croatia Airlines 1 2026-04-14
CTN4426 - 1 2026-04-12

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-14 CTN56E - Apr 14, 07:35 UTCApr 14, 09:00 UTC1h 25m
2026-04-14 CTN456 ZAG → BRU Apr 14, 05:15 UTCApr 14, 06:35 UTC1h 20m
2026-04-13 CTN82W - Apr 13, 19:50 UTCApr 13, 20:10 UTC20m
2026-04-13 CTN82R - Apr 13, 16:35 UTCApr 13, 18:45 UTC2h 10m
2026-04-13 CTN487 - Apr 13, 09:25 UTCApr 13, 11:35 UTC2h 10m
2026-04-13 CTN486 ZAG → ARN Apr 13, 08:20 UTCApr 13, 08:25 UTC5m
2026-04-13 CTN486 ZAG → ARN Apr 13, 07:55 UTCApr 13, 08:25 UTC30m
2026-04-13 CTN486 ZAG → ARN Apr 13, 06:15 UTCApr 13, 08:15 UTC2h 0m
2026-04-12 CTN724D - Apr 12, 18:35 UTCApr 12, 20:00 UTC1h 25m
2026-04-12 CTN4426 - Apr 12, 17:15 UTCApr 12, 17:30 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 9A-CAI page for operator, model, and routing details .

Mode-S 501C3B frequently asked

What is Mode-S code 501C3B?
501C3B is an ICAO 24-bit transponder address. Allocated to Croatia. Assigned to 9A-CAI.
Where is Mode-S 501C3B registered?
Mode-S code 501C3B is allocated to Croatia (HR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 501C3B broadcasting right now?
No active broadcast right now. Last signal was 14h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 501C3B, octal 24016073, decimal 5,250,107.
What flights does 501C3B operate?
Mode-S 501C3B has broadcast 8 distinct callsigns, including CTN486, CTN82W, CTN82R, CTN724D, CTN56E.