sensors Mode-S transponder

3CF3A4

ICAO 24-bit transponder address · allocated to Germany

Currently assigned to D-CTOM · CESSNA 550 Citation S2

Hex
3CF3A4
Octal
17171644
Decimal
3,994,532
Country
DE
Tail
D-CTOM
Type
C550
No current signal · last broadcast 2d ago
Flights observed
4
Distinct callsigns
1
Country
DE
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S 3CF3A4.

Country allocation

The ICAO 24-bit address 3CF3A4 falls within the block assigned to Germany (DE) by ICAO Annex 10, Volume III. Every aircraft registered in Germany 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
DCTOM - 4 2026-04-13

Recent flights last 4

DateFlightRouteTakeoffLandingDuration
2026-04-13 DCTOM - Apr 13, 04:20 UTCApr 13, 05:00 UTC40m
2026-04-13 DCTOM - Apr 13, 04:00 UTCApr 13, 04:15 UTC15m
2026-04-13 DCTOM - Apr 13, 02:20 UTCApr 13, 03:15 UTC55m
2026-04-12 DCTOM - Apr 12, 19:20 UTCApr 12, 19:55 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 D-CTOM page for operator, model, and routing details .

Mode-S 3CF3A4 frequently asked

What is Mode-S code 3CF3A4?
3CF3A4 is an ICAO 24-bit transponder address. Allocated to Germany. Assigned to D-CTOM.
Where is Mode-S 3CF3A4 registered?
Mode-S code 3CF3A4 is allocated to Germany (DE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 3CF3A4 broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 3CF3A4, octal 17171644, decimal 3,994,532.
What flights does 3CF3A4 operate?
Mode-S 3CF3A4 has broadcast 1 distinct callsign, including DCTOM.