Apparatus

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sensors Mode-S transponder

501C4B

ICAO 24-bit transponder address · allocated to Croatia

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

Hex
501C4B
Octal
24016113
Decimal
5,250,123
Country
HR
Tail
9A-CAQ
Type
BCS1
No current signal · last broadcast 40m ago
Flights observed
298
Distinct callsigns
20
Country
HR
Last broadcast
40m ago

Last known position

Most recent position reported by Mode-S 501C4B.

Country allocation

The ICAO 24-bit address 501C4B 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 20 distinct

Callsign Airline Flights Last seen
CTN381 Croatia Airlines 18 2026-05-19
CTN380 Croatia Airlines 18 2026-05-19
CTN56E Croatia Airlines 10 2026-05-28
CTN456 Croatia Airlines 10 2026-05-28
CTN301 Croatia Airlines 10 2026-05-03
CTN461 Croatia Airlines 9 2026-05-19
CTN460 Croatia Airlines 8 2026-05-19
CTN4457 Croatia Airlines 8 2026-05-27
CTN4456 Croatia Airlines 8 2026-05-27
CTN3RC Croatia Airlines 8 2026-05-03
CTN385 Croatia Airlines 8 2026-05-17
CTN384 Croatia Airlines 8 2026-05-17
CTN82W Croatia Airlines 6 2026-05-18
CTN82R Croatia Airlines 6 2026-05-18
CTN438P Croatia Airlines 6 2026-05-30
CTN415 Croatia Airlines 6 2026-05-16
CTN414 Croatia Airlines 6 2026-05-16
CTN724D Croatia Airlines 5 2026-05-26
CTN487 Croatia Airlines 5 2026-05-22
CTN486 Croatia Airlines 5 2026-05-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 CTN438P SPU → MUC May 30, 06:40 UTCMay 30, 08:20 UTC1h 40m
2026-05-29 CTN104C NTE → SPU May 29, 18:55 UTCMay 29, 20:45 UTC1h 50m
2026-05-29 CTN4010 SPU → NTE May 29, 15:55 UTCMay 29, 17:55 UTC2h 0m
2026-05-29 CTN75C ZRH → SPU May 29, 13:45 UTCMay 29, 14:40 UTC55m
2026-05-29 CTN76H SPU → ZRH May 29, 11:30 UTCMay 29, 12:40 UTC1h 10m
2026-05-29 CTN39PR MUC → SPU May 29, 08:55 UTCMay 29, 09:45 UTC50m
2026-05-29 CTN438P SPU → MUC May 29, 06:35 UTCMay 29, 07:40 UTC1h 5m
2026-05-28 CTN4HV VIE → SPU May 28, 19:10 UTCMay 28, 19:45 UTC35m
2026-05-28 CTN4AU SPU → VIE May 28, 17:25 UTCMay 28, 18:05 UTC40m
2026-05-28 CTN658 ZAG → SPU May 28, 16:00 UTCMay 28, 16:20 UTC20m
2026-05-28 CTN56E BRU → ZAG May 28, 07:40 UTCMay 28, 09:05 UTC1h 25m
2026-05-28 CTN456 ZAG → BRU May 28, 05:00 UTCMay 28, 06:45 UTC1h 45m
2026-05-27 CTN4457 BRU → ZAG May 27, 19:10 UTCMay 27, 20:35 UTC1h 25m
2026-05-27 CTN4456 ZAG → BRU May 27, 16:25 UTCMay 27, 18:10 UTC1h 45m
2026-05-27 CTN1311 - May 27, 13:30 UTCMay 27, 13:55 UTC25m
2026-05-27 CTN1311 - May 27, 12:00 UTCMay 27, 12:35 UTC35m
2026-05-27 CTN1310 ZAG → RJK May 27, 09:55 UTCMay 27, 10:40 UTC45m
2026-05-27 CTN6B DBV → ZAG May 27, 04:24 UTCMay 27, 04:59 UTC35m
2026-05-26 CTN664 ZAG → DBV May 26, 20:40 UTCMay 26, 21:20 UTC40m
2026-05-26 CTN4451 AMS → ZAG May 26, 16:30 UTCMay 26, 17:55 UTC1h 25m
2026-05-26 CTN4450 ZAG → AMS May 26, 13:34 UTCMay 26, 15:09 UTC1h 35m
2026-05-26 CTN724D HAM → ZAG May 26, 08:54 UTCMay 26, 10:14 UTC1h 20m
2026-05-26 CTN624D ZAG → HAM May 26, 06:14 UTCMay 26, 07:49 UTC1h 35m
2026-05-26 CTN6B DBV → ZAG May 26, 04:30 UTCMay 26, 05:05 UTC35m
2026-05-25 CTN664 ZAG → DBV May 25, 21:40 UTCMay 25, 22:19 UTC40m
2026-05-25 CTN4457 BRU → ZAG May 25, 18:50 UTCMay 25, 20:15 UTC1h 24m
2026-05-25 CTN4456 ZAG → BRU May 25, 16:25 UTCMay 25, 18:00 UTC1h 35m
2026-05-25 CTN321 - May 25, 12:45 UTCMay 25, 13:30 UTC45m
2026-05-25 CTN320 ZAG → PRG May 25, 10:50 UTCMay 25, 11:45 UTC55m
2026-05-25 CTN56E BRU → ZAG May 25, 08:20 UTCMay 25, 09:45 UTC1h 25m
2026-05-25 CTN456 ZAG → BRU May 25, 05:00 UTCMay 25, 06:25 UTC1h 25m
2026-05-24 CTN724D HAM → ZAG May 24, 19:10 UTCMay 24, 19:55 UTC45m
2026-05-24 CTN724D HAM → ZAG May 24, 18:40 UTCMay 24, 19:05 UTC25m
2026-05-24 CTN624D ZAG → HAM May 24, 16:00 UTCMay 24, 17:35 UTC1h 35m
2026-05-24 CTN5N SPU → ZAG May 24, 12:25 UTCMay 24, 12:40 UTC15m
2026-05-24 CTN2S ZAG → SPU May 24, 10:45 UTCMay 24, 11:10 UTC25m
2026-05-24 CTN9HR FRA → ZAG May 24, 08:40 UTCMay 24, 09:45 UTC1h 5m
2026-05-24 CTN410 ZAG → FRA May 24, 05:50 UTCMay 24, 07:15 UTC1h 25m
2026-05-23 CTN4HV VIE → SPU May 23, 20:45 UTCMay 23, 21:25 UTC40m
2026-05-23 CTN4AU SPU → VIE May 23, 18:20 UTCMay 23, 19:10 UTC50m
2026-05-23 CTN32CZ PRG → SPU May 23, 16:20 UTCMay 23, 17:20 UTC1h 0m
2026-05-23 CTN4324 SPU → PRG May 23, 14:10 UTCMay 23, 15:15 UTC1h 5m
2026-05-23 CTN2S ZAG → SPU May 23, 12:40 UTCMay 23, 13:00 UTC20m
2026-05-23 CTN4AS AMS → ZAG May 23, 09:50 UTCMay 23, 11:15 UTC1h 25m
2026-05-23 CTN5NL ZAG → AMS May 23, 06:45 UTCMay 23, 08:25 UTC1h 40m
2026-05-22 CTN724D HAM → ZAG May 22, 19:00 UTCMay 22, 20:20 UTC1h 20m
2026-05-22 CTN624D ZAG → HAM May 22, 16:15 UTCMay 22, 17:45 UTC1h 30m
2026-05-22 CTN487 ARN → ZAG May 22, 09:35 UTCMay 22, 11:35 UTC2h 0m
2026-05-22 CTN486 ZAG → ARN May 22, 06:20 UTCMay 22, 08:35 UTC2h 15m
2026-05-21 CTN4457 BRU → ZAG May 21, 18:55 UTCMay 21, 20:15 UTC1h 20m

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-CAQ page for operator, model, and routing details .

Mode-S 501C4B frequently asked

What is Mode-S code 501C4B?
501C4B is an ICAO 24-bit transponder address. Allocated to Croatia. Assigned to 9A-CAQ.
Where is Mode-S 501C4B registered?
Mode-S code 501C4B is allocated to Croatia (HR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 501C4B broadcasting right now?
No active broadcast right now. Last signal was 40m ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 501C4B, octal 24016113, decimal 5,250,123.
What flights does 501C4B operate?
Mode-S 501C4B has broadcast 20 distinct callsigns, including CTN381, CTN380, CTN56E, CTN456, CTN301.