sensors Mode-S transponder

45B423

ICAO 24-bit transponder address · allocated to Denmark

Currently assigned to OY-MAC · BOEING 777-200LR

Hex
45B423
Octal
21332043
Decimal
4,568,099
Country
DK
Tail
OY-MAC
Type
B77L
No current signal · last broadcast 2h ago
Flights observed
86
Distinct callsigns
2
Country
DK
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 45B423.

Country allocation

The ICAO 24-bit address 45B423 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 2 distinct

Callsign Airline Flights Last seen
SRR902 Star Air 57 2026-05-29
SRR901 Star Air 29 2026-05-30

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-30 SRR901 BLL → BLL May 30, 03:45 UTCMay 30, 07:30 UTC3h 45m
2026-05-29 SRR902 BLL → BLL May 29, 15:05 UTCMay 29, 16:10 UTC1h 5m
2026-05-29 SRR902 BLL → BLL May 29, 07:20 UTCMay 29, 12:55 UTC5h 35m
2026-05-28 SRR901 BLL → BLL May 28, 03:45 UTCMay 28, 07:30 UTC3h 45m
2026-05-27 SRR902 BLL → BLL May 27, 14:50 UTCMay 27, 16:05 UTC1h 15m
2026-05-27 SRR902 BLL → BLL May 27, 07:40 UTCMay 27, 12:50 UTC5h 10m
2026-05-26 SRR901 BLL → BLL May 26, 03:50 UTCMay 26, 07:55 UTC4h 5m
2026-05-25 SRR902 BLL → BLL May 25, 15:05 UTCMay 25, 16:15 UTC1h 10m
2026-05-25 SRR902 BLL → BLL May 25, 07:30 UTCMay 25, 12:35 UTC5h 5m
2026-05-24 SRR901 BLL → BLL May 24, 03:45 UTCMay 24, 07:50 UTC4h 5m
2026-05-23 SRR902 BLL → BLL May 23, 15:10 UTCMay 23, 16:15 UTC1h 5m
2026-05-23 SRR902 BLL → BLL May 23, 07:35 UTCMay 23, 12:25 UTC4h 50m
2026-05-22 SRR901 BLL → BLL May 22, 03:50 UTCMay 22, 07:55 UTC4h 5m
2026-05-21 SRR902 BLL → BLL May 21, 15:20 UTCMay 21, 16:30 UTC1h 10m
2026-05-21 SRR902 BLL → BLL May 21, 08:15 UTCMay 21, 13:25 UTC5h 10m
2026-05-20 SRR901 BLL → BLL May 20, 03:30 UTCMay 20, 07:40 UTC4h 11m
2026-05-18 SRR902 BLL → BLL May 18, 15:10 UTCMay 18, 16:20 UTC1h 10m
2026-05-18 SRR902 BLL → BLL May 18, 07:15 UTCMay 18, 12:25 UTC5h 10m
2026-05-17 SRR901 BLL → BLL May 17, 03:45 UTCMay 17, 07:50 UTC4h 5m
2026-05-16 SRR902 BLL → BLL May 16, 15:01 UTCMay 16, 16:10 UTC1h 10m
2026-05-16 SRR902 BLL → BLL May 16, 07:11 UTCMay 16, 12:05 UTC4h 55m
2026-05-15 SRR901 BLL → BLL May 15, 03:40 UTCMay 15, 08:05 UTC4h 25m
2026-05-14 SRR902 BLL → BLL May 14, 15:20 UTCMay 14, 16:30 UTC1h 10m
2026-05-14 SRR902 BLL → BLL May 14, 07:25 UTCMay 14, 12:25 UTC5h 0m
2026-05-13 SRR901 BLL → BLL May 13, 03:30 UTCMay 13, 07:25 UTC3h 55m
2026-05-12 SRR902 BLL → BLL May 12, 15:05 UTCMay 12, 16:15 UTC1h 10m
2026-05-12 SRR902 BLL → BLL May 12, 07:30 UTCMay 12, 12:50 UTC5h 20m
2026-05-11 SRR901 BLL → BLL May 11, 04:00 UTCMay 11, 08:10 UTC4h 10m
2026-05-10 SRR902 BLL → BLL May 10, 15:05 UTCMay 10, 16:20 UTC1h 15m
2026-05-10 SRR902 BLL → BLL May 10, 07:40 UTCMay 10, 13:10 UTC5h 30m
2026-05-09 SRR901 BLL → BLL May 9, 03:40 UTCMay 9, 07:50 UTC4h 10m
2026-05-08 SRR902 BLL → BLL May 8, 15:00 UTCMay 8, 16:05 UTC1h 5m
2026-05-08 SRR902 BLL → BLL May 8, 07:34 UTCMay 8, 12:49 UTC5h 15m
2026-05-07 SRR901 BLL → BLL May 7, 03:40 UTCMay 7, 07:50 UTC4h 10m
2026-05-06 SRR902 BLL → BLL May 6, 15:05 UTCMay 6, 16:15 UTC1h 10m
2026-05-06 SRR902 BLL → BLL May 6, 07:45 UTCMay 6, 13:00 UTC5h 15m
2026-05-05 SRR901 BLL → BLL May 5, 03:45 UTCMay 5, 07:55 UTC4h 10m
2026-05-04 SRR902 BLL → BLL May 4, 14:55 UTCMay 4, 16:10 UTC1h 15m
2026-05-04 SRR902 BLL → BLL May 4, 07:30 UTCMay 4, 12:40 UTC5h 10m
2026-05-03 SRR901 BLL → BLL May 3, 04:40 UTCMay 3, 08:45 UTC4h 5m
2026-05-02 SRR902 BLL → BLL May 2, 15:00 UTCMay 2, 16:10 UTC1h 10m
2026-05-02 SRR902 BLL → BLL May 2, 07:20 UTCMay 2, 12:30 UTC5h 10m
2026-05-01 SRR901 BLL → BLL May 1, 03:35 UTCMay 1, 07:40 UTC4h 5m
2026-04-30 SRR902 BLL → BLL Apr 30, 15:10 UTCApr 30, 16:30 UTC1h 20m
2026-04-30 SRR902 BLL → BLL Apr 30, 08:05 UTCApr 30, 13:20 UTC5h 15m
2026-04-29 SRR901 BLL → BLL Apr 29, 03:34 UTCApr 29, 07:29 UTC3h 55m
2026-04-28 SRR902 BLL → BLL Apr 28, 15:00 UTCApr 28, 16:15 UTC1h 15m
2026-04-28 SRR902 BLL → BLL Apr 28, 07:50 UTCApr 28, 13:10 UTC5h 20m
2026-04-27 SRR901 BLL → BLL Apr 27, 04:05 UTCApr 27, 08:00 UTC3h 55m
2026-04-26 SRR902 BLL → BLL Apr 26, 15:15 UTCApr 26, 16:25 UTC1h 10m

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

Mode-S 45B423 frequently asked

What is Mode-S code 45B423?
45B423 is an ICAO 24-bit transponder address. Allocated to Denmark. Assigned to OY-MAC.
Where is Mode-S 45B423 registered?
Mode-S code 45B423 is allocated to Denmark (DK). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 45B423 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 45B423, octal 21332043, decimal 4,568,099.
What flights does 45B423 operate?
Mode-S 45B423 has broadcast 2 distinct callsigns, including SRR902, SRR901.