Apparatus

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sensors Mode-S transponder

3951C1

ICAO 24-bit transponder address · allocated to France

Currently assigned to F-GUOB · BOEING 777-200LR

Hex
3951C1
Octal
16250701
Decimal
3,756,481
Country
FR
Tail
F-GUOB
Type
B77L
Broadcasting now · callsign AFR6733 · 39,000 ft
Flights observed
158
Distinct callsigns
18
Country
FR
Last broadcast
28m ago

Current position

3951C1 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address 3951C1 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 18 distinct

Callsign Airline Flights Last seen
AFR6733 - 19 2026-07-14
AFR6732 - 13 2026-07-13
AFR6727 - 13 2026-07-09
AFR6726 - 13 2026-07-08
AFR6721 - 12 2026-06-24
AFR6728 Air France 11 2026-06-25
AFR6720 - 11 2026-06-23
AFR6729 Air France 9 2026-06-26
AFR6741 - 8 2026-07-13
AFR6740 - 8 2026-07-12
AFR6723 - 8 2026-06-27
AFR6722 - 7 2026-06-26
AFR6735 - 6 2026-07-11
AFR6738 - 5 2026-07-07
AFR6739 - 4 2026-07-08
AFR6737 - 4 2026-07-12
AFR6736 - 4 2026-07-11
AFR6734 - 3 2026-07-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 AFR6733 - Jul 14, 06:00 UTCJul 14, 06:15 UTC15m
2026-07-13 AFR6732 - Jul 13, 18:40 UTCJul 14, 02:40 UTC8h 0m
2026-07-13 AFR6741 - Jul 13, 07:10 UTCJul 13, 15:05 UTC7h 55m
2026-07-12 AFR6740 - Jul 12, 20:10 UTCJul 13, 04:15 UTC8h 5m
2026-07-12 AFR6737 ORD → CDG Jul 12, 08:55 UTCJul 12, 16:35 UTC7h 40m
2026-07-11 AFR6736 - Jul 11, 21:55 UTCJul 12, 06:01 UTC8h 5m
2026-07-11 AFR6735 - Jul 11, 17:45 UTCJul 11, 19:00 UTC1h 15m
2026-07-11 AFR6735 - Jul 11, 08:40 UTCJul 11, 15:15 UTC6h 35m
2026-07-10 AFR6734 - Jul 10, 20:50 UTCJul 11, 05:10 UTC8h 20m
2026-07-10 AFR6733 - Jul 10, 16:30 UTCJul 10, 17:45 UTC1h 15m
2026-07-10 AFR6733 - Jul 10, 08:00 UTCJul 10, 14:40 UTC6h 40m
2026-07-09 AFR6732 - Jul 9, 19:30 UTCJul 10, 04:45 UTC9h 15m
2026-07-09 AFR6727 - Jul 9, 07:45 UTCJul 9, 16:50 UTC9h 5m
2026-07-08 AFR6726 - Jul 8, 19:35 UTCJul 9, 03:40 UTC8h 5m
2026-07-08 AFR6739 ORD → CDG Jul 8, 09:35 UTCJul 8, 17:15 UTC7h 40m
2026-07-07 AFR6738 - Jul 7, 22:20 UTCJul 8, 06:25 UTC8h 5m
2026-07-07 AFR6733 - Jul 7, 18:45 UTCJul 7, 20:05 UTC1h 20m
2026-07-07 AFR6733 ORD → PIK Jul 7, 09:00 UTCJul 7, 15:45 UTC6h 45m
2026-07-06 AFR6732 - Jul 6, 19:40 UTCJul 7, 03:45 UTC8h 5m
2026-07-06 AFR6741 ORD → CDG Jul 6, 07:00 UTCJul 6, 14:35 UTC7h 35m
2026-07-05 AFR6740 - Jul 5, 19:40 UTCJul 6, 03:50 UTC8h 10m
2026-07-05 AFR6737 - Jul 5, 09:00 UTCJul 5, 16:25 UTC7h 25m
2026-07-04 AFR6736 - Jul 4, 21:40 UTCJul 5, 06:00 UTC8h 20m
2026-07-04 AFR6735 - Jul 4, 18:05 UTCJul 4, 19:20 UTC1h 15m
2026-07-04 AFR6735 ORD → DUB Jul 4, 08:50 UTCJul 4, 15:10 UTC6h 20m
2026-07-03 AFR6734 - Jul 3, 20:55 UTCJul 4, 05:50 UTC8h 55m
2026-07-03 AFR6733 ORD → CDG Jul 3, 11:10 UTCJul 3, 18:25 UTC7h 15m
2026-07-03 AFR6732 - Jul 3, 07:55 UTCJul 3, 08:45 UTC50m
2026-07-02 AFR6732 - Jul 2, 19:25 UTCJul 3, 04:05 UTC8h 40m
2026-07-02 AFR6727 - Jul 2, 08:00 UTCJul 2, 16:40 UTC8h 40m
2026-07-01 AFR6726 - Jul 1, 19:10 UTCJul 2, 03:50 UTC8h 40m
2026-07-01 AFR6739 - Jul 1, 08:10 UTCJul 1, 15:25 UTC7h 15m
2026-06-30 AFR6738 - Jun 30, 20:20 UTCJul 1, 04:50 UTC8h 30m
2026-06-30 AFR6733 - Jun 30, 14:35 UTCJun 30, 15:50 UTC1h 15m
2026-06-30 AFR6733 - Jun 30, 06:30 UTCJun 30, 13:00 UTC6h 30m
2026-06-29 AFR6732 - Jun 29, 18:55 UTCJun 30, 03:10 UTC8h 16m
2026-06-29 AFR6741 - Jun 29, 07:50 UTCJun 29, 15:14 UTC7h 25m
2026-06-28 AFR6740 - Jun 28, 19:55 UTCJun 29, 04:20 UTC8h 25m
2026-06-28 AFR6727 - Jun 28, 06:00 UTCJun 28, 14:45 UTC8h 45m
2026-06-28 AFR6726 - Jun 28, 01:29 UTCJun 28, 01:59 UTC30m
2026-06-27 AFR6726 - Jun 27, 17:34 UTCJun 27, 21:44 UTC4h 10m
2026-06-27 AFR6723 - Jun 27, 04:39 UTCJun 27, 14:20 UTC9h 40m
2026-06-26 AFR6722 - Jun 26, 13:24 UTCJun 27, 00:29 UTC11h 5m
2026-06-26 AFR6729 PEK → CDG Jun 26, 04:24 UTCJun 26, 09:00 UTC4h 35m
2026-06-25 AFR6729 PEK → CDG Jun 25, 21:25 UTCJun 25, 21:40 UTC15m
2026-06-25 AFR6728 CDG → PEK Jun 25, 18:04 UTCJun 25, 18:24 UTC20m
2026-06-25 AFR6728 CDG → PEK Jun 25, 07:59 UTCJun 25, 10:50 UTC2h 50m
2026-06-24 AFR6721 - Jun 24, 14:20 UTCJun 25, 05:15 UTC14h 55m
2026-06-23 AFR6720 - Jun 23, 21:29 UTCJun 24, 08:39 UTC11h 10m
2026-06-23 AFR6733 - Jun 23, 15:50 UTCJun 23, 17:04 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.

Prefer a tail-number view? See the F-GUOB page for operator, model, and routing details .

Mode-S 3951C1 frequently asked

What is Mode-S code 3951C1?
3951C1 is an ICAO 24-bit transponder address. Allocated to France. Assigned to F-GUOB.
Where is Mode-S 3951C1 registered?
Mode-S code 3951C1 is allocated to France (FR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 3951C1 broadcasting right now?
Yes. Mode-S 3951C1 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 3951C1, octal 16250701, decimal 3,756,481.
What flights does 3951C1 operate?
Mode-S 3951C1 has broadcast 18 distinct callsigns, including AFR6733, AFR6732, AFR6727, AFR6726, AFR6721.