Apparatus

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sensors Mode-S transponder

406703

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to G-PERD · AGUSTA AW-139

Hex
406703
Octal
20063403
Decimal
4,220,675
Country
GB
Tail
G-PERD
Type
A139
No current signal · last broadcast 5h ago
Flights observed
136
Distinct callsigns
1
Country
GB
Last broadcast
5h ago

Last known position

Most recent position reported by Mode-S 406703.

Country allocation

The ICAO 24-bit address 406703 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
HKS51 - 136 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 HKS51 - Jul 14, 11:55 UTCJul 14, 12:20 UTC25m
2026-07-14 HKS51 - Jul 14, 11:20 UTCJul 14, 11:45 UTC25m
2026-07-14 HKS51 - Jul 14, 09:35 UTCJul 14, 10:30 UTC55m
2026-07-13 HKS51 - Jul 13, 08:25 UTCJul 13, 09:10 UTC45m
2026-07-13 HKS51 - Jul 13, 07:15 UTCJul 13, 07:55 UTC40m
2026-07-10 HKS51 - Jul 10, 15:55 UTCJul 10, 16:15 UTC20m
2026-07-10 HKS51 - Jul 10, 15:35 UTCJul 10, 15:50 UTC15m
2026-07-09 HKS51 - Jul 9, 11:35 UTCJul 9, 11:50 UTC15m
2026-07-09 HKS51 - Jul 9, 10:30 UTCJul 9, 11:30 UTC1h 0m
2026-07-09 HKS51 - Jul 9, 09:55 UTCJul 9, 10:15 UTC20m
2026-07-08 HKS51 - Jul 8, 15:40 UTCJul 8, 16:10 UTC30m
2026-07-08 HKS51 - Jul 8, 14:15 UTCJul 8, 14:45 UTC30m
2026-07-08 HKS51 - Jul 8, 08:50 UTCJul 8, 12:20 UTC3h 30m
2026-07-08 HKS51 - Jul 8, 07:25 UTCJul 8, 07:55 UTC30m
2026-07-07 HKS51 - Jul 7, 10:00 UTCJul 7, 12:20 UTC2h 20m
2026-07-03 HKS51 - Jul 3, 08:40 UTCJul 3, 09:10 UTC30m
2026-07-03 HKS51 - Jul 3, 07:20 UTCJul 3, 07:55 UTC35m
2026-07-02 HKS51 - Jul 2, 10:40 UTCJul 2, 12:40 UTC2h 0m
2026-07-01 HKS51 - Jul 1, 11:50 UTCJul 1, 12:10 UTC20m
2026-07-01 HKS51 - Jul 1, 11:20 UTCJul 1, 11:40 UTC20m
2026-07-01 HKS51 - Jul 1, 08:50 UTCJul 1, 10:20 UTC1h 30m
2026-07-01 HKS51 - Jul 1, 07:20 UTCJul 1, 08:00 UTC40m
2026-06-30 HKS51 - Jun 30, 12:10 UTCJun 30, 12:30 UTC20m
2026-06-30 HKS51 - Jun 30, 11:40 UTCJun 30, 11:55 UTC15m
2026-06-30 HKS51 - Jun 30, 10:10 UTCJun 30, 10:25 UTC15m
2026-06-30 HKS51 - Jun 30, 09:35 UTCJun 30, 09:55 UTC20m
2026-06-29 HKS51 - Jun 29, 10:00 UTCJun 29, 11:10 UTC1h 10m
2026-06-26 HKS51 - Jun 26, 14:09 UTCJun 26, 15:45 UTC1h 35m
2026-06-26 HKS51 - Jun 26, 12:14 UTCJun 26, 12:55 UTC40m
2026-06-26 HKS51 - Jun 26, 09:39 UTCJun 26, 10:39 UTC1h 0m
2026-06-26 HKS51 - Jun 26, 07:14 UTCJun 26, 08:10 UTC55m
2026-06-25 HKS51 - Jun 25, 13:35 UTCJun 25, 13:45 UTC10m
2026-06-25 HKS51 HUY → HUY Jun 25, 11:39 UTCJun 25, 12:04 UTC25m
2026-06-19 HKS51 - Jun 19, 10:29 UTCJun 19, 10:59 UTC30m
2026-06-19 HKS51 - Jun 19, 08:54 UTCJun 19, 09:34 UTC40m
2026-06-18 HKS51 - Jun 18, 10:55 UTCJun 18, 11:45 UTC50m
2026-06-18 HKS51 - Jun 18, 08:50 UTCJun 18, 09:40 UTC50m
2026-06-17 HKS51 - Jun 17, 15:10 UTCJun 17, 15:46 UTC35m
2026-06-17 HKS51 - Jun 17, 13:55 UTCJun 17, 14:25 UTC30m
2026-06-17 HKS51 - Jun 17, 09:50 UTCJun 17, 12:45 UTC2h 55m
2026-06-17 HKS51 - Jun 17, 08:30 UTCJun 17, 09:05 UTC35m
2026-06-16 HKS51 - Jun 16, 11:20 UTCJun 16, 12:10 UTC50m
2026-06-16 HKS51 - Jun 16, 09:34 UTCJun 16, 10:25 UTC50m
2026-06-11 HKS51 - Jun 11, 08:45 UTCJun 11, 11:50 UTC3h 5m
2026-06-11 HKS51 - Jun 11, 07:25 UTCJun 11, 08:00 UTC35m
2026-06-10 HKS51 - Jun 10, 17:10 UTCJun 10, 17:45 UTC35m
2026-06-10 HKS51 - Jun 10, 14:55 UTCJun 10, 16:20 UTC1h 25m
2026-06-10 HKS51 - Jun 10, 13:35 UTCJun 10, 14:10 UTC35m
2026-06-10 HKS51 HUY → HUY Jun 10, 11:20 UTCJun 10, 12:10 UTC50m
2026-06-10 HKS51 - Jun 10, 08:20 UTCJun 10, 10:10 UTC1h 50m

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

Mode-S 406703 frequently asked

What is Mode-S code 406703?
406703 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to G-PERD.
Where is Mode-S 406703 registered?
Mode-S code 406703 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 406703 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 406703, octal 20063403, decimal 4,220,675.
What flights does 406703 operate?
Mode-S 406703 has broadcast 1 distinct callsign, including HKS51.