sensors Mode-S transponder

3909A9

ICAO 24-bit transponder address · allocated to France

Currently assigned to F-GCNJ · CESSNA 152

Hex
3909A9
Octal
16204651
Decimal
3,738,025
Country
FR
Tail
F-GCNJ
Type
C152
No current signal · last broadcast 20h ago
Flights observed
4
Distinct callsigns
1
Country
FR
Last broadcast
20h ago

Last known position

Most recent position reported by Mode-S 3909A9.

Country allocation

The ICAO 24-bit address 3909A9 falls within the block assigned to France (FR) by ICAO Annex 10, Volume III. Every aircraft registered in France 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
FGCNJ - 4 2026-04-14

Recent flights last 4

DateFlightRouteTakeoffLandingDuration
2026-04-14 FGCNJ - Apr 14, 10:55 UTCApr 14, 11:05 UTC10m
2026-04-14 FGCNJ - Apr 14, 09:10 UTCApr 14, 09:30 UTC20m
2026-04-14 FGCNJ - Apr 14, 08:35 UTCApr 14, 09:05 UTC30m
2026-04-12 FGCNJ - Apr 12, 17:25 UTCApr 12, 18:05 UTC40m

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 F-GCNJ page for operator, model, and routing details .

Mode-S 3909A9 frequently asked

What is Mode-S code 3909A9?
3909A9 is an ICAO 24-bit transponder address. Allocated to France. Assigned to F-GCNJ.
Where is Mode-S 3909A9 registered?
Mode-S code 3909A9 is allocated to France (FR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 3909A9 broadcasting right now?
No active broadcast right now. Last signal was 20h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 3909A9, octal 16204651, decimal 3,738,025.
What flights does 3909A9 operate?
Mode-S 3909A9 has broadcast 1 distinct callsign, including FGCNJ.