sensors Mode-S transponder

4A9CEF

ICAO 24-bit transponder address · allocated to Sweden

Currently assigned to SE-GGO · CESSNA 172 Skyhawk

Hex
4A9CEF
Octal
22516357
Decimal
4,889,839
Country
SE
Tail
SE-GGO
Type
C172
No current signal · last broadcast 1h ago
Flights observed
2
Distinct callsigns
1
Country
SE
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 4A9CEF.

Country allocation

The ICAO 24-bit address 4A9CEF 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
SEGGO - 2 2026-05-06

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-05-06 SEGGO - May 6, 09:30 UTCMay 6, 11:40 UTC2h 10m
2026-05-06 SEGGO - May 6, 08:01 UTCMay 6, 08:15 UTC15m

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

Mode-S 4A9CEF frequently asked

What is Mode-S code 4A9CEF?
4A9CEF is an ICAO 24-bit transponder address. Allocated to Sweden. Assigned to SE-GGO.
Where is Mode-S 4A9CEF registered?
Mode-S code 4A9CEF is allocated to Sweden (SE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4A9CEF broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4A9CEF, octal 22516357, decimal 4,889,839.
What flights does 4A9CEF operate?
Mode-S 4A9CEF has broadcast 1 distinct callsign, including SEGGO.