Apparatus

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sensors Mode-S transponder

A4A75C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N39954 · PIPER PA-28-140/150/160/180 · operated by LIPOVETSKY SERGEY J

Hex
A4A75C
Octal
51123534
Decimal
10,790,748
Country
US
Tail
N39954
Type
P28A
Broadcasting now · callsign N39954 · 2,375 ft
Flights observed
58
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Current position

A4A75C is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A4A75C 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
N39954 - 58 2026-07-03

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-03 N39954 MSC → MSC Jul 3, 15:05 UTCJul 3, 16:10 UTC1h 5m
2026-07-02 N39954 - Jul 2, 15:15 UTCJul 2, 16:40 UTC1h 25m
2026-07-02 N39954 MSC → MSC Jul 2, 05:25 UTCJul 2, 08:00 UTC2h 35m
2026-07-01 N39954 - Jul 1, 18:45 UTCJul 1, 19:55 UTC1h 10m
2026-07-01 N39954 - Jul 1, 15:45 UTCJul 1, 17:15 UTC1h 30m
2026-06-30 N39954 - Jun 30, 19:55 UTCJun 30, 20:50 UTC55m
2026-06-30 N39954 - Jun 30, 14:35 UTCJun 30, 15:40 UTC1h 5m
2026-06-30 N39954 - Jun 30, 05:20 UTCJun 30, 07:05 UTC1h 45m
2026-06-29 N39954 - Jun 29, 06:05 UTCJun 29, 06:19 UTC15m
2026-06-27 N39954 - Jun 27, 13:15 UTCJun 27, 14:49 UTC1h 35m
2026-06-27 N39954 - Jun 27, 01:04 UTCJun 27, 01:59 UTC55m
2026-06-26 N39954 - Jun 26, 16:20 UTCJun 26, 18:04 UTC1h 45m
2026-06-26 N39954 - Jun 26, 12:34 UTCJun 26, 14:39 UTC2h 5m
2026-06-25 N39954 - Jun 25, 13:24 UTCJun 25, 14:59 UTC1h 35m
2026-06-25 N39954 HII → MSC Jun 25, 03:59 UTCJun 25, 05:55 UTC1h 55m
2026-06-25 N39954 - Jun 25, 01:04 UTCJun 25, 03:20 UTC2h 15m
2026-06-24 N39954 - Jun 24, 16:54 UTCJun 24, 18:09 UTC1h 15m
2026-06-24 N39954 - Jun 24, 14:34 UTCJun 24, 15:14 UTC40m
2026-06-23 N39954 - Jun 23, 15:59 UTCJun 23, 17:25 UTC1h 25m
2026-06-23 N39954 - Jun 23, 12:25 UTCJun 23, 14:10 UTC1h 45m
2026-06-22 N39954 - Jun 22, 15:45 UTCJun 22, 16:50 UTC1h 5m
2026-06-22 N39954 - Jun 22, 12:15 UTCJun 22, 13:54 UTC1h 40m
2026-06-21 N39954 - Jun 21, 15:34 UTCJun 21, 16:10 UTC35m
2026-06-20 N39954 MSC → MSC Jun 20, 13:29 UTCJun 20, 14:39 UTC1h 10m
2026-06-19 N39954 - Jun 19, 18:54 UTCJun 19, 20:40 UTC1h 45m
2026-06-19 N39954 - Jun 19, 16:25 UTCJun 19, 18:05 UTC1h 40m
2026-06-19 N39954 - Jun 19, 13:54 UTCJun 19, 15:09 UTC1h 15m
2026-06-18 N39954 - Jun 18, 15:20 UTCJun 18, 17:25 UTC2h 5m
2026-06-17 N39954 - Jun 17, 14:45 UTCJun 17, 15:30 UTC45m
2026-06-16 N39954 - Jun 16, 17:19 UTCJun 16, 18:29 UTC1h 10m
2026-06-16 N39954 - Jun 16, 14:39 UTCJun 16, 15:50 UTC1h 10m
2026-06-15 N39954 - Jun 15, 17:25 UTCJun 15, 18:29 UTC1h 5m
2026-06-15 N39954 - Jun 15, 14:00 UTCJun 15, 15:15 UTC1h 15m
2026-06-15 N39954 - Jun 15, 00:29 UTCJun 15, 01:00 UTC30m
2026-06-14 N39954 - Jun 14, 23:00 UTCJun 14, 23:25 UTC25m
2026-06-14 N39954 - Jun 14, 16:25 UTCJun 14, 17:00 UTC35m
2026-06-14 N39954 - Jun 14, 13:55 UTCJun 14, 15:10 UTC1h 15m
2026-06-14 N39954 - Jun 14, 03:15 UTCJun 14, 06:45 UTC3h 31m
2026-06-13 N39954 - Jun 13, 15:15 UTCJun 13, 17:15 UTC2h 0m
2026-06-13 N39954 - Jun 13, 13:15 UTCJun 13, 14:05 UTC50m
2026-06-13 N39954 - Jun 13, 01:25 UTCJun 13, 02:55 UTC1h 30m
2026-06-12 N39954 - Jun 12, 14:10 UTCJun 12, 15:40 UTC1h 30m
2026-06-12 N39954 - Jun 12, 01:30 UTCJun 12, 02:35 UTC1h 5m
2026-06-11 N39954 - Jun 11, 14:40 UTCJun 11, 16:40 UTC2h 0m
2026-06-11 N39954 - Jun 11, 05:05 UTCJun 11, 06:35 UTC1h 30m
2026-06-11 N39954 - Jun 11, 03:00 UTCJun 11, 04:30 UTC1h 30m
2026-06-11 N39954 - Jun 11, 01:35 UTCJun 11, 02:25 UTC50m
2026-06-10 N39954 - Jun 10, 01:00 UTCJun 10, 01:45 UTC45m
2026-06-09 N39954 - Jun 9, 17:05 UTCJun 9, 19:35 UTC2h 30m
2026-06-09 N39954 - Jun 9, 15:00 UTCJun 9, 15:50 UTC50m

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 N39954 page for operator, model, and routing details .

Mode-S A4A75C frequently asked

What is Mode-S code A4A75C?
A4A75C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N39954.
Where is Mode-S A4A75C registered?
Mode-S code A4A75C 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 A4A75C broadcasting right now?
Yes. Mode-S A4A75C is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4A75C, octal 51123534, decimal 10,790,748.
What flights does A4A75C operate?
Mode-S A4A75C has broadcast 1 distinct callsign, including N39954.