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sensors Mode-S transponder

501DD1

ICAO 24-bit transponder address · allocated to Croatia

Currently assigned to 9A-CQF · DE HAVILLAND DHC-8-400 Dash 8

Hex
501DD1
Octal
24016721
Decimal
5,250,513
Country
HR
Tail
9A-CQF
Type
DH8D
No current signal · last broadcast Jul 26, 21:50 UTC
Flights observed
698
Distinct callsigns
20
Country
HR
Last broadcast
Jul 26, 21:50 UTC

Last known position

Most recent position reported by Mode-S 501DD1.

Country allocation

The ICAO 24-bit address 501DD1 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
CTN342 Croatia Airlines 35 2026-07-25
CTN341 Croatia Airlines 35 2026-07-26
CTN6CH Croatia Airlines 34 2026-07-26
CTN465 Croatia Airlines 33 2026-07-26
CTN632 - 32 2026-07-13
CTN4W Croatia Airlines 31 2026-07-24
CTN3T - 31 2026-07-14
CTN4AT - 26 2026-07-20
CTN443 Croatia Airlines 26 2026-07-24
CTN441 - 26 2026-07-20
CTN442 - 25 2026-07-24
CTN344 - 25 2026-07-16
CTN461 - 24 2026-07-15
CTN460 Croatia Airlines 24 2026-07-22
CTN345 Croatia Airlines 23 2026-07-16
CTN4437 Croatia Airlines 16 2026-07-24
CTN436R Croatia Airlines 16 2026-07-24
CTN4Z Croatia Airlines 15 2026-07-24
CTN640 Croatia Airlines 12 2026-07-22
CTN641 Croatia Airlines 11 2026-07-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 CTN326 ZAG → OMO Jul 26, 21:25 UTCJul 26, 21:50 UTC25m
2026-07-26 CTN465 ZRH → ZAG Jul 26, 18:30 UTCJul 26, 19:45 UTC1h 15m
2026-07-26 CTN6CH ZAG → ZRH Jul 26, 16:30 UTCJul 26, 17:45 UTC1h 15m
2026-07-26 CTN6D DBV → ZAG Jul 26, 13:40 UTCJul 26, 14:35 UTC55m
2026-07-26 CTN660 ZAG → DBV Jul 26, 12:05 UTCJul 26, 12:50 UTC45m
2026-07-26 CTN341 SJJ → ZAG Jul 26, 04:45 UTCJul 26, 05:15 UTC30m
2026-07-25 CTN342 ZAG → SJJ Jul 25, 20:10 UTCJul 25, 20:30 UTC20m
2026-07-25 CTN465 ZRH → ZAG Jul 25, 18:10 UTCJul 25, 19:20 UTC1h 10m
2026-07-25 CTN6CH - Jul 25, 16:00 UTCJul 25, 17:10 UTC1h 10m
2026-07-25 CTN341 SJJ → ZAG Jul 25, 04:40 UTCJul 25, 05:05 UTC25m
2026-07-24 CTN342 ZAG → SJJ Jul 24, 20:40 UTCJul 24, 21:00 UTC20m
2026-07-24 CTN443 VIE → ZAG Jul 24, 17:40 UTCJul 24, 18:10 UTC30m
2026-07-24 CTN442 - Jul 24, 16:00 UTCJul 24, 16:35 UTC35m
2026-07-24 CTN4Z PUY → ZAG Jul 24, 14:25 UTCJul 24, 14:40 UTC15m
2026-07-24 CTN4W ZAG → ZAD Jul 24, 13:20 UTCJul 24, 13:35 UTC15m
2026-07-24 CTN4W ZAG → ZAD Jul 24, 12:15 UTCJul 24, 12:30 UTC15m
2026-07-24 CTN4437 MUC → ZAG Jul 24, 08:30 UTCJul 24, 09:15 UTC45m
2026-07-24 CTN436R ZAG → MUC Jul 24, 06:30 UTCJul 24, 07:25 UTC55m
2026-07-24 CTN341 SJJ → ZAG Jul 24, 04:30 UTCJul 24, 04:55 UTC25m
2026-07-23 CTN342 ZAG → SJJ Jul 23, 20:10 UTCJul 23, 20:35 UTC25m
2026-07-23 CTN443 VIE → ZAG Jul 23, 18:05 UTCJul 23, 18:40 UTC35m
2026-07-23 CTN442 - Jul 23, 16:25 UTCJul 23, 17:10 UTC45m
2026-07-23 CTN341 SJJ → ZAG Jul 23, 04:30 UTCJul 23, 05:00 UTC30m
2026-07-22 CTN342 ZAG → SJJ Jul 22, 20:05 UTCJul 22, 20:30 UTC25m
2026-07-22 CTN641 BWK → ZAG Jul 22, 17:20 UTCJul 22, 17:40 UTC20m
2026-07-22 CTN640 ZAG → BWK Jul 22, 15:55 UTCJul 22, 16:10 UTC15m
2026-07-22 CTN4Z PUY → ZAG Jul 22, 14:40 UTCJul 22, 15:00 UTC20m
2026-07-22 CTN4W ZAG → ZAD Jul 22, 13:40 UTCJul 22, 14:00 UTC20m
2026-07-22 CTN4W ZAG → ZAD Jul 22, 12:25 UTCJul 22, 12:45 UTC20m
2026-07-22 CTN460 ZAG → ZRH Jul 22, 11:10 UTCJul 22, 11:35 UTC25m
2026-07-21 CTN415 FRA → ZAG Jul 21, 19:45 UTCJul 21, 20:55 UTC1h 10m
2026-07-21 CTN414 - Jul 21, 16:05 UTCJul 21, 17:35 UTC1h 30m
2026-07-21 CTN341 - Jul 21, 04:40 UTCJul 21, 05:10 UTC30m
2026-07-20 CTN342 ZAG → SJJ Jul 20, 20:20 UTCJul 20, 20:45 UTC25m
2026-07-20 CTN437 - Jul 20, 18:05 UTCJul 20, 18:50 UTC45m
2026-07-20 CTN436 ZAG → MUC Jul 20, 16:15 UTCJul 20, 17:10 UTC55m
2026-07-20 CTN4Z PUY → ZAG Jul 20, 14:25 UTCJul 20, 14:45 UTC20m
2026-07-20 CTN4W ZAG → ZAD Jul 20, 13:30 UTCJul 20, 13:45 UTC15m
2026-07-20 CTN4W ZAG → ZAD Jul 20, 12:20 UTCJul 20, 12:35 UTC15m
2026-07-20 CTN441 - Jul 20, 07:55 UTCJul 20, 08:35 UTC40m
2026-07-20 CTN4AT - Jul 20, 06:10 UTCJul 20, 06:45 UTC35m
2026-07-20 CTN327 OMO → ZAG Jul 20, 04:15 UTCJul 20, 04:45 UTC30m
2026-07-19 CTN326 ZAG → OMO Jul 19, 21:35 UTCJul 19, 22:05 UTC30m
2026-07-19 CTN465 ZRH → ZAG Jul 19, 18:30 UTCJul 19, 19:25 UTC55m
2026-07-19 CTN6CH - Jul 19, 16:20 UTCJul 19, 17:35 UTC1h 15m
2026-07-18 CTN465 ZRH → ZAG Jul 18, 19:10 UTCJul 18, 20:10 UTC1h 0m
2026-07-18 CTN6CH - Jul 18, 16:45 UTCJul 18, 18:20 UTC1h 35m
2026-07-18 CTN641 BWK → ZAG Jul 18, 15:15 UTCJul 18, 15:25 UTC10m
2026-07-18 CTN245T - Jul 18, 13:15 UTCJul 18, 14:10 UTC55m
2026-07-18 CTN442T - Jul 18, 11:30 UTCJul 18, 12:20 UTC50m

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

Mode-S 501DD1 frequently asked

What is Mode-S code 501DD1?
501DD1 is an ICAO 24-bit transponder address. Allocated to Croatia. Assigned to 9A-CQF.
Where is Mode-S 501DD1 registered?
Mode-S code 501DD1 is allocated to Croatia (HR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 501DD1 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:50 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 501DD1, octal 24016721, decimal 5,250,513.
What flights does 501DD1 operate?
Mode-S 501DD1 has broadcast 20 distinct callsigns, including CTN342, CTN341, CTN6CH, CTN465, CTN632.