sensors Mode-S transponder

4AB423

ICAO 24-bit transponder address · allocated to Sweden

Currently assigned to SE-MAC · DE HAVILLAND DHC-8-300 Dash 8

Hex
4AB423
Octal
22532043
Decimal
4,895,779
Country
SE
Tail
SE-MAC
Type
DH8C
No current signal · last broadcast 1d ago
Flights observed
5
Distinct callsigns
1
Country
SE
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 4AB423.

Country allocation

The ICAO 24-bit address 4AB423 falls within the block assigned to Sweden (SE) by ICAO Annex 10, Volume III. Every aircraft registered in Sweden 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 1 distinct

Callsign Airline Flights Last seen
KBV503 - 5 2026-05-18

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-05-18 KBV503 - May 18, 23:50 UTCMay 19, 00:30 UTC40m
2026-05-18 KBV503 - May 18, 19:30 UTCMay 18, 22:50 UTC3h 20m
2026-05-16 KBV503 - May 16, 10:40 UTCMay 16, 12:16 UTC1h 35m
2026-05-14 KBV503 - May 14, 08:25 UTCMay 14, 08:35 UTC10m
2026-05-10 KBV503 - May 10, 11:15 UTCMay 10, 11:35 UTC20m

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

Mode-S 4AB423 frequently asked

What is Mode-S code 4AB423?
4AB423 is an ICAO 24-bit transponder address. Allocated to Sweden. Assigned to SE-MAC.
Where is Mode-S 4AB423 registered?
Mode-S code 4AB423 is allocated to Sweden (SE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4AB423 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4AB423, octal 22532043, decimal 4,895,779.
What flights does 4AB423 operate?
Mode-S 4AB423 has broadcast 1 distinct callsign, including KBV503.