sensors Mode-S transponder

390831

ICAO 24-bit transponder address · allocated to France

Hex
390831
Octal
16204061
Decimal
3,737,649
Country
FR
No current signal · last broadcast 2h ago
Flights observed
5
Distinct callsigns
4
Country
FR
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S 390831.

Country allocation

The ICAO 24-bit address 390831 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 4 distinct

Callsign Airline Flights Last seen
CSR06 - 2 2026-05-11
CSR54 - 1 2026-05-05
CSR32 - 1 2026-05-05
CSR105 - 1 2026-05-07

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-05-11 CSR06 - May 11, 20:30 UTCMay 11, 21:50 UTC1h 20m
2026-05-11 CSR06 - May 11, 17:15 UTCMay 11, 17:50 UTC35m
2026-05-07 CSR105 - May 7, 13:45 UTCMay 7, 14:45 UTC1h 0m
2026-05-05 CSR54 - May 5, 17:30 UTCMay 5, 18:35 UTC1h 5m
2026-05-05 CSR32 - May 5, 14:05 UTCMay 5, 15:20 UTC1h 15m

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.

Mode-S 390831 frequently asked

What is Mode-S code 390831?
390831 is an ICAO 24-bit transponder address. Allocated to France.
Where is Mode-S 390831 registered?
Mode-S code 390831 is allocated to France (FR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 390831 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 390831, octal 16204061, decimal 3,737,649.
What flights does 390831 operate?
Mode-S 390831 has broadcast 4 distinct callsigns, including CSR06, CSR54, CSR32, CSR105.