sensors Mode-S transponder

39D2A1

ICAO 24-bit transponder address · allocated to France

Currently assigned to F-HUVB · AIRBUS A-350-900

Hex
39D2A1
Octal
16351241
Decimal
3,789,473
Country
FR
Tail
F-HUVB
Type
A359
Photo of F-HUVB
Broadcasting now · callsign AFR53M · 6,300 ft
Flights observed
9
Distinct callsigns
4
Country
FR
Last broadcast
21h ago

Current position

39D2A1 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 39D2A1 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
AFR178 Air France 4 2026-04-13
AFR179 Air France 3 2026-04-14
AFR334M - 1 2026-04-12
AFR333F Air France 1 2026-04-13

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-14 AFR179 MEX → CDG Apr 14, 10:40 UTCApr 14, 11:05 UTC25m
2026-04-14 AFR179 MEX → CDG Apr 14, 07:10 UTCApr 14, 07:25 UTC15m
2026-04-14 AFR179 MEX → CDG Apr 14, 05:15 UTCApr 14, 07:10 UTC1h 55m
2026-04-13 AFR178 CDG → MEX Apr 13, 19:50 UTCApr 13, 23:35 UTC3h 45m
2026-04-13 AFR178 CDG → MEX Apr 13, 17:40 UTCApr 13, 20:10 UTC2h 30m
2026-04-13 AFR178 CDG → MEX Apr 13, 12:20 UTCApr 13, 13:35 UTC1h 15m
2026-04-13 AFR178 CDG → MEX Apr 13, 12:00 UTCApr 13, 12:15 UTC15m
2026-04-13 AFR333F BOS → CDG Apr 13, 02:00 UTCApr 13, 03:30 UTC1h 30m
2026-04-12 AFR334M - Apr 12, 17:20 UTCApr 12, 18:45 UTC1h 25m

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

Mode-S 39D2A1 frequently asked

What is Mode-S code 39D2A1?
39D2A1 is an ICAO 24-bit transponder address. Allocated to France. Assigned to F-HUVB.
Where is Mode-S 39D2A1 registered?
Mode-S code 39D2A1 is allocated to France (FR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 39D2A1 broadcasting right now?
Yes. Mode-S 39D2A1 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 39D2A1, octal 16351241, decimal 3,789,473.
What flights does 39D2A1 operate?
Mode-S 39D2A1 has broadcast 4 distinct callsigns, including AFR178, AFR179, AFR334M, AFR333F.