sensors Mode-S transponder

45A18D

ICAO 24-bit transponder address · allocated to Denmark

Currently assigned to OY-HLM · AGUSTA AW-189

Hex
45A18D
Octal
21320615
Decimal
4,563,341
Country
DK
Tail
OY-HLM
Type
A189
No current signal · last broadcast 15h ago
Flights observed
8
Distinct callsigns
5
Country
DK
Last broadcast
15h ago

Last known position

Most recent position reported by Mode-S 45A18D.

Country allocation

The ICAO 24-bit address 45A18D 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
BBX609 - 2 2026-04-14
BBX604 - 2 2026-04-14
BBX603 - 2 2026-04-14
BBX615 - 1 2026-04-13
BBX610 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 BBX609 - Apr 14, 09:40 UTCApr 14, 09:55 UTC15m
2026-04-14 BBX604 - Apr 14, 08:05 UTCApr 14, 08:25 UTC20m
2026-04-14 BBX603 - Apr 14, 06:00 UTCApr 14, 06:15 UTC15m
2026-04-13 BBX615 - Apr 13, 12:50 UTCApr 13, 13:00 UTC10m
2026-04-13 BBX610 - Apr 13, 10:50 UTCApr 13, 11:15 UTC25m
2026-04-13 BBX609 - Apr 13, 09:15 UTCApr 13, 09:30 UTC15m
2026-04-13 BBX604 - Apr 13, 07:50 UTCApr 13, 08:05 UTC15m
2026-04-13 BBX603 - Apr 13, 05:55 UTCApr 13, 06:30 UTC35m

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

Mode-S 45A18D frequently asked

What is Mode-S code 45A18D?
45A18D is an ICAO 24-bit transponder address. Allocated to Denmark. Assigned to OY-HLM.
Where is Mode-S 45A18D registered?
Mode-S code 45A18D is allocated to Denmark (DK). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 45A18D broadcasting right now?
No active broadcast right now. Last signal was 15h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 45A18D, octal 21320615, decimal 4,563,341.
What flights does 45A18D operate?
Mode-S 45A18D has broadcast 5 distinct callsigns, including BBX609, BBX604, BBX603, BBX615, BBX610.