sensors Mode-S transponder

406C79

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-MCGE · SIKORSKY S-92 Helibus

Hex
406C79
Octal
20066171
Decimal
4,222,073
Country
GB
Tail
G-MCGE
Type
S92
Photo of G-MCGE
No current signal · last broadcast 1d ago
Flights observed
4
Distinct callsigns
3
Country
GB
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 406C79.

Country allocation

The ICAO 24-bit address 406C79 falls within the block assigned to United Kingdom (GB) by ICAO Annex 10, Volume III. Every aircraft registered in United Kingdom 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 3 distinct

Callsign Airline Flights Last seen
SRD912 - 2 2026-04-13
SRG912E - 1 2026-04-13
SRG912A - 1 2026-04-13

Recent flights last 4

DateFlightRouteTakeoffLandingDuration
2026-04-13 SRD912 - Apr 13, 19:50 UTCApr 13, 20:50 UTC1h 0m
2026-04-13 SRD912 - Apr 13, 18:55 UTCApr 13, 20:10 UTC1h 15m
2026-04-13 SRG912E - Apr 13, 12:20 UTCApr 13, 13:20 UTC1h 0m
2026-04-13 SRG912A - Apr 13, 12:00 UTCApr 13, 12:15 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 G-MCGE page for operator, model, and routing details .

Mode-S 406C79 frequently asked

What is Mode-S code 406C79?
406C79 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-MCGE.
Where is Mode-S 406C79 registered?
Mode-S code 406C79 is allocated to United Kingdom (GB). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 406C79 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 406C79, octal 20066171, decimal 4,222,073.
What flights does 406C79 operate?
Mode-S 406C79 has broadcast 3 distinct callsigns, including SRD912, SRG912E, SRG912A.