sensors Mode-S transponder

A57D55

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N453AV · operated by WESTWIND SCHOOL OF AERONAUTICS PHOENIX LLC DBA, UNITED AVIATE ACADEMY

Hex
A57D55
Octal
51276525
Decimal
10,845,525
Country
US
Tail
N453AV
Type
SR20
No current signal · last broadcast 1d ago
Flights observed
9
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A57D55.

Country allocation

The ICAO 24-bit address A57D55 falls within the block assigned to United States (US) by ICAO Annex 10, Volume III. Every aircraft registered in United States 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
VAR453 - 9 2026-04-13

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-13 VAR453 BXK → GYR Apr 13, 20:45 UTCApr 13, 21:55 UTC1h 10m
2026-04-13 VAR453 - Apr 13, 19:50 UTCApr 13, 20:00 UTC10m
2026-04-13 VAR453 GYR → BXK Apr 13, 18:55 UTCApr 13, 20:00 UTC1h 5m
2026-04-13 VAR453 - Apr 13, 15:50 UTCApr 13, 16:00 UTC10m
2026-04-13 VAR453 GYR → GYR Apr 13, 14:50 UTCApr 13, 16:00 UTC1h 10m
2026-04-13 VAR453 - Apr 13, 04:20 UTCApr 13, 05:40 UTC1h 20m
2026-04-13 VAR453 - Apr 13, 03:55 UTCApr 13, 04:15 UTC20m
2026-04-13 VAR453 GYR → AZA Apr 13, 00:30 UTCApr 13, 02:35 UTC2h 5m
2026-04-12 VAR453 - Apr 12, 17:15 UTCApr 12, 17:45 UTC30m

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 N453AV page for operator, model, and routing details .

Mode-S A57D55 frequently asked

What is Mode-S code A57D55?
A57D55 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N453AV.
Where is Mode-S A57D55 registered?
Mode-S code A57D55 is allocated to United States (US). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is A57D55 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 A57D55, octal 51276525, decimal 10,845,525.
What flights does A57D55 operate?
Mode-S A57D55 has broadcast 1 distinct callsign, including VAR453.