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sensors Mode-S transponder

A4A444

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N399AM · PILATUS PC-12 · operated by UNIVERSITY OF UTAH

Hex
A4A444
Octal
51122104
Decimal
10,789,956
Country
US
Tail
N399AM
Type
PC12
No current signal · last broadcast 16h ago
Flights observed
138
Distinct callsigns
1
Country
US
Last broadcast
16h ago

Last known position

Most recent position reported by Mode-S A4A444.

Country allocation

The ICAO 24-bit address A4A444 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
N399AM - 138 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 N399AM - Jul 26, 18:40 UTCJul 26, 20:30 UTC1h 50m
2026-07-26 N399AM - Jul 26, 14:05 UTCJul 26, 15:55 UTC1h 50m
2026-07-26 N399AM - Jul 26, 06:10 UTCJul 26, 07:30 UTC1h 21m
2026-07-26 N399AM - Jul 26, 02:45 UTCJul 26, 04:15 UTC1h 30m
2026-07-25 N399AM - Jul 25, 07:00 UTCJul 25, 07:15 UTC15m
2026-07-25 N399AM - Jul 25, 05:10 UTCJul 25, 05:30 UTC20m
2026-07-25 N399AM - Jul 25, 00:20 UTCJul 25, 01:00 UTC40m
2026-07-24 N399AM - Jul 24, 23:20 UTCJul 24, 23:35 UTC15m
2026-07-24 N399AM - Jul 24, 19:45 UTCJul 24, 20:35 UTC50m
2026-07-24 N399AM - Jul 24, 05:35 UTCJul 24, 05:50 UTC15m
2026-07-24 N399AM - Jul 24, 03:50 UTCJul 24, 04:05 UTC15m
2026-07-23 N399AM VGT → SLC Jul 23, 09:45 UTCJul 23, 11:20 UTC1h 35m
2026-07-23 N399AM - Jul 23, 06:35 UTCJul 23, 08:00 UTC1h 25m
2026-07-22 N399AM PVU → SLC Jul 22, 18:50 UTCJul 22, 19:15 UTC25m
2026-07-22 N399AM - Jul 22, 16:45 UTCJul 22, 17:30 UTC45m
2026-07-22 N399AM - Jul 22, 14:25 UTCJul 22, 15:25 UTC1h 0m
2026-07-21 N399AM - Jul 21, 20:40 UTCJul 21, 21:15 UTC35m
2026-07-21 N399AM - Jul 21, 17:40 UTCJul 21, 18:10 UTC30m
2026-07-19 N399AM - Jul 19, 05:45 UTCJul 19, 06:15 UTC30m
2026-07-19 N399AM - Jul 19, 02:55 UTCJul 19, 03:35 UTC40m
2026-07-18 N399AM - Jul 18, 06:20 UTCJul 18, 06:30 UTC10m
2026-07-18 N399AM - Jul 18, 03:25 UTCJul 18, 03:45 UTC20m
2026-07-16 N399AM - Jul 16, 22:59 UTCJul 16, 23:20 UTC20m
2026-07-16 N399AM - Jul 16, 16:09 UTCJul 16, 16:40 UTC30m
2026-07-16 N399AM - Jul 16, 13:34 UTCJul 16, 14:20 UTC45m
2026-07-15 N399AM - Jul 15, 00:10 UTCJul 15, 00:25 UTC15m
2026-07-14 N399AM - Jul 14, 19:55 UTCJul 14, 20:45 UTC50m
2026-07-13 N399AM - Jul 13, 21:35 UTCJul 13, 22:05 UTC30m
2026-07-13 N399AM - Jul 13, 20:00 UTCJul 13, 20:20 UTC20m
2026-07-12 N399AM - Jul 12, 05:01 UTCJul 12, 05:15 UTC15m
2026-07-12 N399AM - Jul 12, 02:25 UTCJul 12, 02:50 UTC25m
2026-07-10 N399AM - Jul 10, 04:50 UTCJul 10, 06:05 UTC1h 15m
2026-07-10 N399AM - Jul 10, 03:05 UTCJul 10, 03:20 UTC15m
2026-07-10 N399AM - Jul 10, 01:55 UTCJul 10, 02:35 UTC40m
2026-07-08 N399AM - Jul 8, 14:15 UTCJul 8, 15:20 UTC1h 5m
2026-07-08 N399AM - Jul 8, 12:30 UTCJul 8, 13:35 UTC1h 5m
2026-07-07 N399AM - Jul 7, 23:15 UTCJul 8, 00:05 UTC50m
2026-07-07 N399AM - Jul 7, 20:35 UTCJul 7, 20:45 UTC10m
2026-07-07 N399AM - Jul 7, 17:55 UTCJul 7, 18:30 UTC35m
2026-07-07 N399AM - Jul 7, 08:25 UTCJul 7, 08:40 UTC15m
2026-07-07 N399AM - Jul 7, 05:55 UTCJul 7, 06:10 UTC15m
2026-07-06 N399AM - Jul 6, 04:25 UTCJul 6, 04:40 UTC15m
2026-07-05 N399AM - Jul 5, 11:55 UTCJul 5, 12:15 UTC20m
2026-07-05 N399AM - Jul 5, 10:45 UTCJul 5, 11:15 UTC30m
2026-07-05 N399AM - Jul 5, 08:15 UTCJul 5, 08:55 UTC40m
2026-07-05 N399AM - Jul 5, 07:25 UTCJul 5, 07:45 UTC20m
2026-07-04 N399AM - Jul 4, 09:55 UTCJul 4, 10:35 UTC40m
2026-07-04 N399AM - Jul 4, 05:45 UTCJul 4, 06:30 UTC45m
2026-07-03 N399AM - Jul 3, 10:30 UTCJul 3, 11:35 UTC1h 5m
2026-07-03 N399AM - Jul 3, 08:05 UTCJul 3, 09:15 UTC1h 10m

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 N399AM page for operator, model, and routing details .

Mode-S A4A444 frequently asked

What is Mode-S code A4A444?
A4A444 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N399AM.
Where is Mode-S A4A444 registered?
Mode-S code A4A444 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 A4A444 broadcasting right now?
No active broadcast right now. Last signal was 16h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4A444, octal 51122104, decimal 10,789,956.
What flights does A4A444 operate?
Mode-S A4A444 has broadcast 1 distinct callsign, including N399AM.