sensors Mode-S transponder

43F701

ICAO 24-bit transponder address · allocated to United Kingdom

Currently assigned to 2-HWDN · BOMBARDIER CL-600 Challenger

Hex
43F701
Octal
20773401
Decimal
4,454,145
Country
GB
Tail
2-HWDN
Type
CL60
No current signal · last broadcast 1d ago
Flights observed
3
Distinct callsigns
1
Country
GB
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S 43F701.

Country allocation

The ICAO 24-bit address 43F701 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
VLZ61X - 3 2026-04-13

Recent flights last 3

DateFlightRouteTakeoffLandingDuration
2026-04-13 VLZ61X - Apr 13, 15:50 UTCApr 13, 15:55 UTC5m
2026-04-13 VLZ61X - Apr 13, 15:30 UTCApr 13, 15:55 UTC25m
2026-04-13 VLZ61X BQH → ABZ Apr 13, 13:35 UTCApr 13, 14:40 UTC1h 5m

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 2-HWDN page for operator, model, and routing details .

Mode-S 43F701 frequently asked

What is Mode-S code 43F701?
43F701 is an ICAO 24-bit transponder address. Allocated to United Kingdom. Assigned to 2-HWDN.
Where is Mode-S 43F701 registered?
Mode-S code 43F701 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 43F701 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 43F701, octal 20773401, decimal 4,454,145.
What flights does 43F701 operate?
Mode-S 43F701 has broadcast 1 distinct callsign, including VLZ61X.