Apparatus

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sensors Mode-S transponder

A4B423

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N402AV · operated by WESTWIND SCHOOL OR AERONAUTICS PHOENIX LLC, UNITED AVIATE ACADEMY

Hex
A4B423
Octal
51132043
Decimal
10,794,019
Country
US
Tail
N402AV
Type
SR20
No current signal · last broadcast 7h ago
Flights observed
104
Distinct callsigns
1
Country
US
Last broadcast
7h ago

Last known position

Most recent position reported by Mode-S A4B423.

Country allocation

The ICAO 24-bit address A4B423 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
VAR402 - 104 2026-07-01

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-01 VAR402 GYR → GYR Jul 1, 03:45 UTCJul 1, 05:05 UTC1h 20m
2026-06-30 VAR402 HII → GYR Jun 30, 23:05 UTCJul 1, 01:00 UTC1h 55m
2026-06-30 VAR402 GYR → HII Jun 30, 19:45 UTCJun 30, 21:45 UTC2h 0m
2026-06-30 VAR402 GYR → GYR Jun 30, 16:10 UTCJun 30, 17:45 UTC1h 35m
2026-06-30 VAR402 - Jun 30, 04:05 UTCJun 30, 05:00 UTC55m
2026-06-30 VAR402 GYR → BXK Jun 30, 03:35 UTCJun 30, 03:55 UTC20m
2026-06-30 VAR402 - Jun 30, 00:00 UTCJun 30, 02:10 UTC2h 10m
2026-06-29 VAR402 GYR → GYR Jun 29, 20:44 UTCJun 29, 22:59 UTC2h 15m
2026-06-29 VAR402 GYR → GYR Jun 29, 05:00 UTCJun 29, 05:09 UTC10m
2026-06-29 VAR402 BXK → GYR Jun 29, 04:04 UTCJun 29, 04:55 UTC50m
2026-06-29 VAR402 - Jun 29, 03:39 UTCJun 29, 04:00 UTC20m
2026-06-29 VAR402 GYR → GYR Jun 29, 00:10 UTCJun 29, 02:09 UTC2h 0m
2026-06-28 VAR402 GYR → GYR Jun 28, 20:54 UTCJun 28, 23:04 UTC2h 10m
2026-06-28 VAR402 - Jun 28, 18:34 UTCJun 28, 18:49 UTC15m
2026-06-28 VAR402 - Jun 28, 17:55 UTCJun 28, 18:25 UTC30m
2026-06-28 VAR402 GYR → GYR Jun 28, 15:49 UTCJun 28, 16:39 UTC50m
2026-06-28 VAR402 - Jun 28, 14:25 UTCJun 28, 14:39 UTC15m
2026-06-28 VAR402 - Jun 28, 14:04 UTCJun 28, 14:14 UTC10m
2026-06-28 VAR402 - Jun 28, 13:34 UTCJun 28, 13:55 UTC20m
2026-06-27 VAR402 BXK → GYR Jun 27, 22:04 UTCJun 27, 23:19 UTC1h 15m
2026-06-27 VAR402 GYR → BXK Jun 27, 19:45 UTCJun 27, 20:59 UTC1h 15m
2026-06-26 VAR402 HII → GYR Jun 26, 23:44 UTCJun 27, 01:35 UTC1h 50m
2026-06-26 VAR402 - Jun 26, 22:05 UTCJun 26, 22:34 UTC30m
2026-06-26 VAR402 - Jun 26, 20:44 UTCJun 26, 21:30 UTC45m
2026-06-26 VAR402 GYR → GYR Jun 26, 19:04 UTCJun 26, 19:20 UTC15m
2026-06-26 VAR402 GYR → GYR Jun 26, 15:49 UTCJun 26, 17:15 UTC1h 25m
2026-06-25 VAR402 - Jun 25, 19:09 UTCJun 25, 21:10 UTC2h 0m
2026-06-25 VAR402 - Jun 25, 15:34 UTCJun 25, 17:09 UTC1h 35m
2026-06-23 VAR402 GYR → GYR Jun 23, 17:25 UTCJun 23, 18:25 UTC1h 0m
2026-06-23 VAR402 - Jun 23, 04:14 UTCJun 23, 05:49 UTC1h 35m
2026-06-23 VAR402 GYR → TUS Jun 23, 01:04 UTCJun 23, 02:45 UTC1h 40m
2026-06-22 VAR402 GYR → GYR Jun 22, 21:59 UTCJun 22, 23:45 UTC1h 45m
2026-06-22 VAR402 GYR → GYR Jun 22, 18:24 UTCJun 22, 20:24 UTC2h 0m
2026-06-22 VAR402 GYR → GYR Jun 22, 15:05 UTCJun 22, 17:15 UTC2h 10m
2026-06-21 VAR402 - Jun 21, 23:44 UTCJun 22, 01:29 UTC1h 45m
2026-06-21 VAR402 - Jun 21, 19:29 UTCJun 21, 21:14 UTC1h 45m
2026-06-21 VAR402 GYR → GYR Jun 21, 16:59 UTCJun 21, 17:50 UTC50m
2026-06-21 VAR402 GYR → GYR Jun 21, 03:05 UTCJun 21, 04:44 UTC1h 40m
2026-06-20 VAR402 - Jun 20, 23:34 UTCJun 21, 00:59 UTC1h 25m
2026-06-20 VAR402 - Jun 20, 20:40 UTCJun 20, 20:45 UTC5m
2026-06-20 VAR402 - Jun 20, 14:59 UTCJun 20, 17:49 UTC2h 50m
2026-06-20 VAR402 GYR → GYR Jun 20, 13:04 UTCJun 20, 14:19 UTC1h 15m
2026-06-20 VAR402 - Jun 20, 04:39 UTCJun 20, 04:44 UTC5m
2026-06-20 VAR402 GYR → GYR Jun 20, 01:05 UTCJun 20, 02:49 UTC1h 45m
2026-06-19 VAR402 GYR → GYR Jun 19, 22:04 UTCJun 19, 23:49 UTC1h 45m
2026-06-19 VAR402 GYR → GYR Jun 19, 18:54 UTCJun 19, 19:45 UTC50m
2026-06-19 VAR402 - Jun 19, 17:09 UTCJun 19, 17:29 UTC20m
2026-06-19 VAR402 - Jun 19, 15:49 UTCJun 19, 16:09 UTC20m
2026-06-19 VAR402 GYR → GYR Jun 19, 04:10 UTCJun 19, 06:20 UTC2h 10m
2026-06-18 VAR402 GYR → GYR Jun 18, 23:55 UTCJun 19, 02:09 UTC2h 14m

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 N402AV page for operator, model, and routing details .

Mode-S A4B423 frequently asked

What is Mode-S code A4B423?
A4B423 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N402AV.
Where is Mode-S A4B423 registered?
Mode-S code A4B423 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 A4B423 broadcasting right now?
No active broadcast right now. Last signal was 7h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4B423, octal 51132043, decimal 10,794,019.
What flights does A4B423 operate?
Mode-S A4B423 has broadcast 1 distinct callsign, including VAR402.