Apparatus

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sensors Mode-S transponder

45CAAF

ICAO 24-bit transponder address · allocated to Denmark

Currently assigned to OY-RUO · ATR-42-500

Hex
45CAAF
Octal
21345257
Decimal
4,573,871
Country
DK
Tail
OY-RUO
Type
AT45
No current signal · last broadcast 15d ago
Flights observed
256
Distinct callsigns
20
Country
DK
Last broadcast
15d ago

Last known position

Most recent position reported by Mode-S 45CAAF.

Country allocation

The ICAO 24-bit address 45CAAF falls within the block assigned to Denmark (DK) by ICAO Annex 10, Volume III. Every aircraft registered in Denmark 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
DTR546 - 33 2026-06-25
DTR44S - 30 2026-06-25
DTR45S - 28 2026-06-26
DTR43S - 28 2026-06-25
DTR41S - 24 2026-06-24
DTR42S - 23 2026-06-25
DTR522 - 19 2026-06-28
DTR523 - 18 2026-06-28
DTR521 DAT Danish Air Transport 17 2026-05-01
DTR524 DAT Danish Air Transport 14 2026-04-30
DTR47S DAT Danish Air Transport 5 2026-06-21
DTR526 - 4 2026-06-28
DTR525 - 4 2026-06-28
DTR42F - 2 2026-05-29
DTR542 - 1 2026-06-16
DTR52S - 1 2026-05-26
DTR51S DAT Danish Air Transport 1 2026-05-26
DTR446 DAT Danish Air Transport 1 2026-06-01
DTR41F - 1 2026-05-29
DNU983 - 1 2026-06-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-28 DNU983 - Jun 28, 17:34 UTCJun 28, 19:44 UTC2h 10m
2026-06-28 DTR526 - Jun 28, 16:14 UTCJun 28, 16:45 UTC30m
2026-06-28 DTR525 - Jun 28, 14:54 UTCJun 28, 15:34 UTC40m
2026-06-28 DTR522 - Jun 28, 11:55 UTCJun 28, 12:25 UTC30m
2026-06-28 DTR523 - Jun 28, 10:35 UTCJun 28, 11:09 UTC35m
2026-06-26 DTR45S - Jun 26, 16:24 UTCJun 26, 17:00 UTC35m
2026-06-26 DTR45S - Jun 26, 15:05 UTCJun 26, 15:45 UTC40m
2026-06-25 DTR546 - Jun 25, 16:29 UTCJun 25, 17:14 UTC45m
2026-06-25 DTR45S - Jun 25, 14:50 UTCJun 25, 15:34 UTC45m
2026-06-25 DTR44S - Jun 25, 13:05 UTCJun 25, 13:55 UTC50m
2026-06-25 DTR43S - Jun 25, 11:35 UTCJun 25, 12:19 UTC45m
2026-06-25 DTR42S - Jun 25, 06:30 UTCJun 25, 07:15 UTC45m
2026-06-25 DTR546 - Jun 25, 05:05 UTCJun 25, 05:50 UTC45m
2026-06-24 DTR546 - Jun 24, 16:19 UTCJun 24, 17:05 UTC45m
2026-06-24 DTR45S - Jun 24, 14:50 UTCJun 24, 15:35 UTC45m
2026-06-24 DTR44S - Jun 24, 09:45 UTCJun 24, 10:49 UTC1h 5m
2026-06-24 DTR43S - Jun 24, 08:14 UTCJun 24, 08:55 UTC40m
2026-06-24 DTR42S - Jun 24, 06:39 UTCJun 24, 07:30 UTC50m
2026-06-24 DTR41S - Jun 24, 05:09 UTCJun 24, 05:49 UTC40m
2026-06-23 DTR546 - Jun 23, 16:20 UTCJun 23, 17:09 UTC50m
2026-06-23 DTR45S - Jun 23, 14:49 UTCJun 23, 15:30 UTC40m
2026-06-23 DTR44S - Jun 23, 13:09 UTCJun 23, 13:59 UTC50m
2026-06-23 DTR43S - Jun 23, 11:35 UTCJun 23, 12:25 UTC50m
2026-06-23 DTR42S - Jun 23, 06:39 UTCJun 23, 07:29 UTC50m
2026-06-23 DTR41S - Jun 23, 05:09 UTCJun 23, 05:49 UTC40m
2026-06-22 DTR546 - Jun 22, 16:20 UTCJun 22, 17:04 UTC45m
2026-06-22 DTR45S - Jun 22, 14:49 UTCJun 22, 15:35 UTC45m
2026-06-22 DTR42S - Jun 22, 06:45 UTCJun 22, 07:30 UTC45m
2026-06-22 DTR41S - Jun 22, 05:10 UTCJun 22, 05:49 UTC40m
2026-06-21 DTR546 - Jun 21, 17:05 UTCJun 21, 17:50 UTC45m
2026-06-21 DTR47S SRP → OSL Jun 21, 15:30 UTCJun 21, 16:10 UTC40m
2026-06-21 DTR44S - Jun 21, 12:55 UTCJun 21, 13:44 UTC50m
2026-06-21 DTR43S - Jun 21, 11:05 UTCJun 21, 11:49 UTC45m
2026-06-17 DTR546 OSL → SRP Jun 17, 16:25 UTCJun 17, 17:15 UTC50m
2026-06-17 DTR45S SRP → OSL Jun 17, 14:45 UTCJun 17, 15:30 UTC45m
2026-06-17 DTR44S OSL → SRP Jun 17, 09:45 UTCJun 17, 10:35 UTC50m
2026-06-17 DTR43S SRP → OSL Jun 17, 08:10 UTCJun 17, 08:50 UTC40m
2026-06-17 DTR41S SRP → OSL Jun 17, 06:40 UTCJun 17, 07:30 UTC50m
2026-06-17 DTR41S SRP → OSL Jun 17, 05:05 UTCJun 17, 05:45 UTC40m
2026-06-16 DTR546 OSL → SRP Jun 16, 16:30 UTCJun 16, 17:10 UTC40m
2026-06-16 DTR45S SRP → OSL Jun 16, 14:45 UTCJun 16, 15:24 UTC40m
2026-06-16 DTR44S OSL → SRP Jun 16, 13:15 UTCJun 16, 14:00 UTC45m
2026-06-16 DTR43S SRP → OSL Jun 16, 11:45 UTCJun 16, 12:25 UTC40m
2026-06-16 DTR542 - Jun 16, 06:50 UTCJun 16, 07:30 UTC40m
2026-06-16 DTR41S SRP → OSL Jun 16, 05:15 UTCJun 16, 05:59 UTC45m
2026-06-15 DTR546 OSL → SRP Jun 15, 16:19 UTCJun 15, 17:04 UTC45m
2026-06-15 DTR45S SRP → OSL Jun 15, 14:40 UTCJun 15, 15:25 UTC45m
2026-06-15 DTR42S OSL → SRP Jun 15, 06:45 UTCJun 15, 07:25 UTC40m
2026-06-15 DTR41S SRP → OSL Jun 15, 05:04 UTCJun 15, 05:45 UTC40m
2026-06-14 DTR546 OSL → SRP Jun 14, 17:25 UTCJun 14, 18:05 UTC40m

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 OY-RUO page for operator, model, and routing details .

Mode-S 45CAAF frequently asked

What is Mode-S code 45CAAF?
45CAAF is an ICAO 24-bit transponder address. Allocated to Denmark. Assigned to OY-RUO.
Where is Mode-S 45CAAF registered?
Mode-S code 45CAAF is allocated to Denmark (DK). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 45CAAF broadcasting right now?
No active broadcast right now. Last signal was 15d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 45CAAF, octal 21345257, decimal 4,573,871.
What flights does 45CAAF operate?
Mode-S 45CAAF has broadcast 20 distinct callsigns, including DTR546, DTR44S, DTR45S, DTR43S, DTR41S.