Apparatus

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sensors Mode-S transponder

406942

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-SNSI · AGUSTA AW-139

Hex
406942
Octal
20064502
Decimal
4,221,250
Country
GB
Tail
G-SNSI
Type
A139
No current signal · last broadcast 5h ago
Flights observed
182
Distinct callsigns
1
Country
GB
Last broadcast
5h ago

Last known position

Most recent position reported by Mode-S 406942.

Country allocation

The ICAO 24-bit address 406942 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 1 distinct

Callsign Airline Flights Last seen
HKS39 - 182 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 HKS39 - Jul 14, 10:10 UTCJul 14, 11:25 UTC1h 15m
2026-07-14 HKS39 NWI → NWI Jul 14, 07:05 UTCJul 14, 08:30 UTC1h 25m
2026-07-13 HKS39 NWI → NWI Jul 13, 08:20 UTCJul 13, 08:45 UTC25m
2026-07-09 HKS39 - Jul 9, 14:50 UTCJul 9, 16:20 UTC1h 30m
2026-07-09 HKS39 - Jul 9, 12:55 UTCJul 9, 13:05 UTC10m
2026-07-09 HKS39 - Jul 9, 11:35 UTCJul 9, 12:20 UTC45m
2026-07-09 HKS39 - Jul 9, 08:20 UTCJul 9, 09:30 UTC1h 10m
2026-07-08 HKS39 - Jul 8, 10:05 UTCJul 8, 10:35 UTC30m
2026-07-08 HKS39 - Jul 8, 08:10 UTCJul 8, 08:50 UTC40m
2026-07-07 HKS39 - Jul 7, 11:10 UTCJul 7, 11:25 UTC15m
2026-07-07 HKS39 - Jul 7, 10:10 UTCJul 7, 10:25 UTC15m
2026-07-06 HKS39 NWI → NWI Jul 6, 12:10 UTCJul 6, 14:40 UTC2h 30m
2026-07-05 HKS39 - Jul 5, 13:05 UTCJul 5, 13:50 UTC45m
2026-07-05 HKS39 - Jul 5, 08:20 UTCJul 5, 09:10 UTC50m
2026-07-04 HKS39 - Jul 4, 12:40 UTCJul 4, 14:25 UTC1h 45m
2026-07-04 HKS39 - Jul 4, 09:20 UTCJul 4, 09:40 UTC20m
2026-07-04 HKS39 - Jul 4, 08:10 UTCJul 4, 08:40 UTC30m
2026-07-03 HKS39 - Jul 3, 09:20 UTCJul 3, 09:35 UTC15m
2026-07-03 HKS39 - Jul 3, 07:15 UTCJul 3, 07:50 UTC35m
2026-06-30 HKS39 - Jun 30, 13:40 UTCJun 30, 13:50 UTC10m
2026-06-30 HKS39 - Jun 30, 12:45 UTCJun 30, 13:00 UTC15m
2026-06-30 HKS39 - Jun 30, 11:10 UTCJun 30, 11:25 UTC15m
2026-06-30 HKS39 - Jun 30, 10:10 UTCJun 30, 10:30 UTC20m
2026-06-27 HKS39 - Jun 27, 09:55 UTCJun 27, 10:40 UTC45m
2026-06-27 HKS39 - Jun 27, 08:14 UTCJun 27, 08:55 UTC40m
2026-06-25 HKS39 - Jun 25, 14:39 UTCJun 25, 15:10 UTC30m
2026-06-25 HKS39 - Jun 25, 13:55 UTCJun 25, 14:29 UTC35m
2026-06-24 HKS39 - Jun 24, 09:55 UTCJun 24, 10:25 UTC30m
2026-06-24 HKS39 - Jun 24, 08:04 UTCJun 24, 08:39 UTC35m
2026-06-23 HKS39 NWI → NWI Jun 23, 10:15 UTCJun 23, 11:24 UTC1h 10m
2026-06-22 HKS39 - Jun 22, 13:54 UTCJun 22, 15:24 UTC1h 30m
2026-06-18 HKS39 - Jun 18, 15:20 UTCJun 18, 16:10 UTC50m
2026-06-18 HKS39 - Jun 18, 10:30 UTCJun 18, 11:25 UTC55m
2026-06-18 HKS39 - Jun 18, 07:10 UTCJun 18, 08:05 UTC55m
2026-06-17 HKS39 - Jun 17, 14:35 UTCJun 17, 14:50 UTC15m
2026-06-17 HKS39 - Jun 17, 13:35 UTCJun 17, 13:50 UTC15m
2026-06-17 HKS39 - Jun 17, 12:00 UTCJun 17, 12:25 UTC25m
2026-06-17 HKS39 - Jun 17, 11:15 UTCJun 17, 11:30 UTC15m
2026-06-17 HKS39 NWI → NWI Jun 17, 10:00 UTCJun 17, 11:10 UTC1h 10m
2026-06-17 HKS39 NWI → NWI Jun 17, 07:10 UTCJun 17, 07:55 UTC45m
2026-06-16 HKS39 - Jun 16, 14:50 UTCJun 16, 15:15 UTC25m
2026-06-16 HKS39 - Jun 16, 12:35 UTCJun 16, 13:09 UTC35m
2026-06-16 HKS39 - Jun 16, 11:20 UTCJun 16, 11:30 UTC10m
2026-06-16 HKS39 - Jun 16, 10:15 UTCJun 16, 10:35 UTC20m
2026-06-15 HKS39 NWI → NWI Jun 15, 16:40 UTCJun 15, 17:30 UTC50m
2026-06-15 HKS39 - Jun 15, 07:10 UTCJun 15, 08:00 UTC50m
2026-06-14 HKS39 - Jun 14, 16:35 UTCJun 14, 16:45 UTC10m
2026-06-14 HKS39 NWI → NWI Jun 14, 07:10 UTCJun 14, 08:00 UTC50m
2026-06-13 HKS39 - Jun 13, 17:20 UTCJun 13, 17:35 UTC15m
2026-06-13 HKS39 - Jun 13, 16:40 UTCJun 13, 16:50 UTC10m

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

Mode-S 406942 frequently asked

What is Mode-S code 406942?
406942 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-SNSI.
Where is Mode-S 406942 registered?
Mode-S code 406942 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 406942 broadcasting right now?
No active broadcast right now. Last signal was 5h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 406942, octal 20064502, decimal 4,221,250.
What flights does 406942 operate?
Mode-S 406942 has broadcast 1 distinct callsign, including HKS39.