Apparatus

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sensors Mode-S transponder

A4B71C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N4025F · CESSNA 172 Skyhawk · operated by WESTOPLEX HOLDINGS LLC

Hex
A4B71C
Octal
51133434
Decimal
10,794,780
Country
US
Tail
N4025F
Type
C172
No current signal · last broadcast 5d ago
Flights observed
101
Distinct callsigns
1
Country
US
Last broadcast
5d ago

Last known position

Most recent position reported by Mode-S A4B71C.

Country allocation

The ICAO 24-bit address A4B71C 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
N4025F - 101 2026-07-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-21 N4025F - Jul 21, 00:35 UTCJul 21, 01:40 UTC1h 5m
2026-07-20 N4025F - Jul 20, 19:25 UTCJul 20, 19:40 UTC15m
2026-07-20 N4025F - Jul 20, 17:45 UTCJul 20, 18:00 UTC15m
2026-07-20 N4025F - Jul 20, 14:25 UTCJul 20, 15:00 UTC35m
2026-07-20 N4025F - Jul 20, 13:05 UTCJul 20, 13:25 UTC20m
2026-07-20 N4025F - Jul 20, 12:15 UTCJul 20, 12:25 UTC10m
2026-07-19 N4025F - Jul 19, 02:20 UTCJul 19, 03:00 UTC40m
2026-07-14 N4025F - Jul 14, 23:50 UTCJul 15, 00:05 UTC15m
2026-07-11 N4025F - Jul 11, 15:50 UTCJul 11, 16:15 UTC25m
2026-07-10 N4025F - Jul 10, 18:20 UTCJul 10, 20:30 UTC2h 10m
2026-07-10 N4025F - Jul 10, 15:00 UTCJul 10, 16:15 UTC1h 15m
2026-07-09 N4025F - Jul 9, 16:20 UTCJul 9, 16:30 UTC10m
2026-07-09 N4025F - Jul 9, 13:10 UTCJul 9, 13:25 UTC15m
2026-07-07 N4025F - Jul 7, 13:45 UTCJul 7, 14:10 UTC25m
2026-07-05 N4025F - Jul 5, 02:20 UTCJul 5, 02:45 UTC25m
2026-07-02 N4025F - Jul 2, 18:45 UTCJul 2, 19:35 UTC50m
2026-06-30 N4025F - Jun 30, 19:45 UTCJun 30, 20:00 UTC15m
2026-06-30 N4025F - Jun 30, 17:55 UTCJun 30, 18:05 UTC10m
2026-06-30 N4025F - Jun 30, 15:10 UTCJun 30, 15:45 UTC35m
2026-06-27 N4025F - Jun 27, 14:45 UTCJun 27, 15:24 UTC40m
2026-06-26 N4025F - Jun 26, 16:24 UTCJun 26, 17:59 UTC1h 35m
2026-06-26 N4025F - Jun 26, 13:59 UTCJun 26, 14:09 UTC10m
2026-06-25 N4025F - Jun 25, 21:44 UTCJun 25, 22:04 UTC20m
2026-06-25 N4025F - Jun 25, 20:39 UTCJun 25, 20:59 UTC20m
2026-06-25 N4025F - Jun 25, 14:14 UTCJun 25, 14:50 UTC35m
2026-06-24 N4025F - Jun 24, 17:05 UTCJun 24, 17:45 UTC40m
2026-06-24 N4025F - Jun 24, 15:24 UTCJun 24, 16:05 UTC40m
2026-06-24 N4025F - Jun 24, 14:00 UTCJun 24, 14:15 UTC15m
2026-06-22 N4025F - Jun 22, 19:24 UTCJun 22, 19:49 UTC25m
2026-06-19 N4025F - Jun 19, 21:30 UTCJun 19, 23:00 UTC1h 30m
2026-06-18 N4025F - Jun 18, 17:55 UTCJun 18, 18:20 UTC25m
2026-06-18 N4025F - Jun 18, 15:35 UTCJun 18, 15:45 UTC10m
2026-06-17 N4025F - Jun 17, 23:35 UTCJun 18, 00:00 UTC25m
2026-06-17 N4025F - Jun 17, 17:40 UTCJun 17, 18:05 UTC25m
2026-06-17 N4025F - Jun 17, 15:25 UTCJun 17, 15:35 UTC10m
2026-06-17 N4025F - Jun 17, 14:05 UTCJun 17, 14:40 UTC35m
2026-06-16 N4025F - Jun 16, 19:55 UTCJun 16, 20:30 UTC35m
2026-06-15 N4025F - Jun 15, 20:10 UTCJun 15, 20:25 UTC15m
2026-06-13 N4025F - Jun 13, 17:10 UTCJun 13, 17:25 UTC15m
2026-06-13 N4025F - Jun 13, 16:00 UTCJun 13, 16:30 UTC30m
2026-06-13 N4025F - Jun 13, 14:05 UTCJun 13, 14:25 UTC20m
2026-06-11 N4025F - Jun 11, 22:55 UTCJun 11, 23:30 UTC35m
2026-06-11 N4025F - Jun 11, 20:35 UTCJun 11, 21:10 UTC35m
2026-06-11 N4025F - Jun 11, 15:25 UTCJun 11, 15:55 UTC30m
2026-06-10 N4025F - Jun 10, 22:50 UTCJun 10, 23:50 UTC1h 0m
2026-06-10 N4025F - Jun 10, 20:55 UTCJun 10, 21:25 UTC30m
2026-06-10 N4025F - Jun 10, 15:55 UTCJun 10, 16:05 UTC10m
2026-06-09 N4025F - Jun 9, 18:10 UTCJun 9, 18:55 UTC45m
2026-05-30 N4025F MWL → MWL May 30, 14:00 UTCMay 30, 14:40 UTC40m
2026-05-29 N4025F - May 29, 19:40 UTCMay 29, 20:25 UTC45m

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 N4025F page for operator, model, and routing details .

Mode-S A4B71C frequently asked

What is Mode-S code A4B71C?
A4B71C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N4025F.
Where is Mode-S A4B71C registered?
Mode-S code A4B71C 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 A4B71C broadcasting right now?
No active broadcast right now. Last signal was 5d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A4B71C, octal 51133434, decimal 10,794,780.
What flights does A4B71C operate?
Mode-S A4B71C has broadcast 1 distinct callsign, including N4025F.