Apparatus

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sensors Mode-S transponder

398C4E

ICAO 24-bit transponder address · allocated to France

Currently assigned to F-HDCO · AIRBUS HELICOPTERS EC-135/635

Hex
398C4E
Octal
16306116
Decimal
3,771,470
Country
FR
Tail
F-HDCO
Type
EC35
Transponder active on ground
Flights observed
24
Distinct callsigns
1
Country
FR
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S 398C4E.

Country allocation

The ICAO 24-bit address 398C4E 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
SAMU71 - 24 2026-04-18

Recent flights last 24

DateFlightRouteTakeoffLandingDuration
2026-04-18 SAMU71 - Apr 18, 17:05 UTCApr 18, 17:30 UTC25m
2026-04-18 SAMU71 - Apr 18, 16:00 UTCApr 18, 16:25 UTC25m
2026-04-18 SAMU71 - Apr 18, 15:00 UTCApr 18, 15:15 UTC15m
2026-04-18 SAMU71 - Apr 18, 12:50 UTCApr 18, 13:00 UTC10m
2026-04-18 SAMU71 - Apr 18, 10:45 UTCApr 18, 10:55 UTC10m
2026-04-17 SAMU71 - Apr 17, 21:05 UTCApr 17, 21:15 UTC10m
2026-04-17 SAMU71 - Apr 17, 20:10 UTCApr 17, 20:30 UTC20m
2026-04-17 SAMU71 - Apr 17, 19:05 UTCApr 17, 19:20 UTC15m
2026-04-17 SAMU71 - Apr 17, 14:15 UTCApr 17, 14:45 UTC30m
2026-04-17 SAMU71 - Apr 17, 12:30 UTCApr 17, 12:50 UTC20m
2026-04-17 SAMU71 - Apr 17, 11:40 UTCApr 17, 11:55 UTC15m
2026-04-17 SAMU71 - Apr 17, 00:40 UTCApr 17, 00:50 UTC10m
2026-04-16 SAMU71 - Apr 16, 23:50 UTCApr 17, 00:00 UTC10m
2026-04-16 SAMU71 - Apr 16, 16:40 UTCApr 16, 17:10 UTC30m
2026-04-16 SAMU71 - Apr 16, 15:50 UTCApr 16, 16:00 UTC10m
2026-04-16 SAMU71 - Apr 16, 15:15 UTCApr 16, 15:25 UTC10m
2026-04-16 SAMU71 - Apr 16, 06:34 UTCApr 16, 06:40 UTC5m
2026-04-15 SAMU71 - Apr 15, 17:05 UTCApr 15, 18:10 UTC1h 5m
2026-04-15 SAMU71 - Apr 15, 10:15 UTCApr 15, 10:45 UTC30m
2026-04-15 SAMU71 - Apr 15, 09:00 UTCApr 15, 09:10 UTC10m
2026-04-15 SAMU71 - Apr 15, 08:01 UTCApr 15, 08:15 UTC15m
2026-04-14 SAMU71 - Apr 14, 23:40 UTCApr 15, 00:30 UTC50m
2026-04-14 SAMU71 - Apr 14, 22:55 UTCApr 14, 23:10 UTC15m
2026-04-14 SAMU71 - Apr 14, 21:45 UTCApr 14, 22:00 UTC15m

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

Mode-S 398C4E frequently asked

What is Mode-S code 398C4E?
398C4E is an ICAO 24-bit transponder address. Allocated to France. Assigned to F-HDCO.
Where is Mode-S 398C4E registered?
Mode-S code 398C4E is allocated to France (FR). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 398C4E broadcasting right now?
Mode-S 398C4E is currently broadcasting from the ground.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 398C4E, octal 16306116, decimal 3,771,470.
What flights does 398C4E operate?
Mode-S 398C4E has broadcast 1 distinct callsign, including SAMU71.