Apparatus

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sensors Mode-S transponder

45CF23

ICAO 24-bit transponder address · allocated to Denmark

Currently assigned to OY-SYC · BOEING 767-300

Hex
45CF23
Octal
21347443
Decimal
4,575,011
Country
DK
Tail
OY-SYC
Type
B763
No current signal · last broadcast 3h ago
Flights observed
131
Distinct callsigns
5
Country
DK
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S 45CF23.

Country allocation

The ICAO 24-bit address 45CF23 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 5 distinct

Callsign Airline Flights Last seen
UPS292 United Parcel Service 63 2026-05-29
UPS291 United Parcel Service 61 2026-05-29
SRR6498 Star Air 4 2026-05-28
SRR6497 Star Air 2 2026-05-28
UPS293 - 1 2026-05-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 UPS291 ARN → HEL May 29, 22:05 UTCMay 29, 23:10 UTC1h 5m
2026-05-29 UPS291 ARN → HEL May 29, 19:05 UTCMay 29, 20:20 UTC1h 15m
2026-05-29 UPS292 CGN → HEL May 29, 03:55 UTCMay 29, 05:10 UTC1h 15m
2026-05-29 UPS292 CGN → HEL May 29, 01:50 UTCMay 29, 02:50 UTC1h 0m
2026-05-28 SRR6497 BLQ → CGN May 28, 21:30 UTCMay 28, 22:55 UTC1h 25m
2026-05-28 SRR6498 CGN → BLQ May 28, 04:40 UTCMay 28, 05:05 UTC25m
2026-05-28 SRR6498 CGN → BLQ May 28, 02:20 UTCMay 28, 03:15 UTC55m
2026-05-27 SRR6497 BLQ → CGN May 27, 20:10 UTCMay 27, 21:25 UTC1h 15m
2026-05-27 SRR6498 CGN → BLQ May 27, 04:39 UTCMay 27, 05:09 UTC30m
2026-05-27 SRR6498 CGN → BLQ May 27, 02:29 UTCMay 27, 03:29 UTC1h 0m
2026-05-26 UPS291 ARN → HEL May 26, 19:10 UTCMay 26, 20:29 UTC1h 20m
2026-05-26 UPS292 CGN → HEL May 26, 03:40 UTCMay 26, 04:50 UTC1h 10m
2026-05-26 UPS292 CGN → HEL May 26, 01:44 UTCMay 26, 02:44 UTC1h 0m
2026-05-25 UPS291 ARN → HEL May 25, 20:55 UTCMay 25, 22:30 UTC1h 35m
2026-05-25 UPS291 ARN → HEL May 25, 19:00 UTCMay 25, 19:50 UTC49m
2026-05-25 UPS292 CGN → HEL May 25, 03:00 UTCMay 25, 03:35 UTC35m
2026-05-22 UPS291 ARN → HEL May 22, 21:30 UTCMay 22, 22:35 UTC1h 5m
2026-05-22 UPS291 ARN → HEL May 22, 19:15 UTCMay 22, 20:25 UTC1h 10m
2026-05-22 UPS292 CGN → HEL May 22, 04:25 UTCMay 22, 05:40 UTC1h 15m
2026-05-22 UPS292 CGN → HEL May 22, 02:05 UTCMay 22, 03:05 UTC1h 0m
2026-05-21 UPS291 ARN → HEL May 21, 22:05 UTCMay 21, 23:10 UTC1h 5m
2026-05-21 UPS291 ARN → HEL May 21, 19:25 UTCMay 21, 20:35 UTC1h 10m
2026-05-21 UPS292 CGN → HEL May 21, 03:45 UTCMay 21, 04:50 UTC1h 5m
2026-05-21 UPS292 CGN → HEL May 21, 01:35 UTCMay 21, 02:35 UTC1h 0m
2026-05-20 UPS291 ARN → HEL May 20, 21:40 UTCMay 20, 23:05 UTC1h 25m
2026-05-20 UPS291 ARN → HEL May 20, 19:35 UTCMay 20, 20:50 UTC1h 15m
2026-05-20 UPS292 CGN → HEL May 20, 04:10 UTCMay 20, 05:20 UTC1h 11m
2026-05-20 UPS292 CGN → HEL May 20, 02:00 UTCMay 20, 03:05 UTC1h 5m
2026-05-19 UPS291 ARN → HEL May 19, 21:40 UTCMay 19, 22:45 UTC1h 5m
2026-05-19 UPS291 ARN → HEL May 19, 19:25 UTCMay 19, 20:40 UTC1h 15m
2026-05-19 UPS292 CGN → HEL May 19, 03:45 UTCMay 19, 04:55 UTC1h 10m
2026-05-19 UPS292 CGN → HEL May 19, 01:50 UTCMay 19, 02:45 UTC55m
2026-05-18 UPS291 ARN → HEL May 18, 20:55 UTCMay 18, 22:40 UTC1h 45m
2026-05-18 UPS291 ARN → HEL May 18, 19:05 UTCMay 18, 19:45 UTC40m
2026-05-18 UPS292 CGN → HEL May 18, 03:05 UTCMay 18, 03:40 UTC35m
2026-05-18 UPS292 CGN → HEL May 18, 00:30 UTCMay 18, 02:05 UTC1h 35m
2026-05-15 UPS291 ARN → HEL May 15, 21:30 UTCMay 15, 22:40 UTC1h 10m
2026-05-15 UPS291 ARN → HEL May 15, 19:10 UTCMay 15, 20:25 UTC1h 15m
2026-05-15 UPS292 CGN → HEL May 15, 04:35 UTCMay 15, 05:50 UTC1h 15m
2026-05-15 UPS292 CGN → HEL May 15, 01:40 UTCMay 15, 02:40 UTC1h 0m
2026-05-14 UPS293 - May 14, 19:10 UTCMay 14, 21:15 UTC2h 5m
2026-05-14 UPS292 CGN → HEL May 14, 03:45 UTCMay 14, 04:55 UTC1h 10m
2026-05-14 UPS292 CGN → HEL May 14, 01:45 UTCMay 14, 02:35 UTC50m
2026-05-13 UPS291 ARN → HEL May 13, 21:45 UTCMay 13, 22:55 UTC1h 10m
2026-05-13 UPS291 ARN → HEL May 13, 19:20 UTCMay 13, 20:40 UTC1h 20m
2026-05-13 UPS292 CGN → HEL May 13, 04:15 UTCMay 13, 05:20 UTC1h 5m
2026-05-13 UPS292 CGN → HEL May 13, 02:00 UTCMay 13, 02:55 UTC55m
2026-05-12 UPS291 ARN → HEL May 12, 21:40 UTCMay 12, 22:50 UTC1h 10m
2026-05-12 UPS291 ARN → HEL May 12, 19:30 UTCMay 12, 20:45 UTC1h 15m
2026-05-12 UPS292 CGN → HEL May 12, 04:15 UTCMay 12, 05:20 UTC1h 5m

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

Mode-S 45CF23 frequently asked

What is Mode-S code 45CF23?
45CF23 is an ICAO 24-bit transponder address. Allocated to Denmark. Assigned to OY-SYC.
Where is Mode-S 45CF23 registered?
Mode-S code 45CF23 is allocated to Denmark (DK). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 45CF23 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 45CF23, octal 21347443, decimal 4,575,011.
What flights does 45CF23 operate?
Mode-S 45CF23 has broadcast 5 distinct callsigns, including UPS292, UPS291, SRR6498, SRR6497, UPS293.