Apparatus

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sensors Mode-S transponder

A66C3D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N5127U · CESSNA 206 Stationair · operated by FOWLER RON W

Hex
A66C3D
Octal
51466075
Decimal
10,906,685
Country
US
Tail
N5127U
Type
C206
No current signal · last broadcast 13d ago
Flights observed
26
Distinct callsigns
1
Country
US
Last broadcast
13d ago

Last known position

Most recent position reported by Mode-S A66C3D.

Country allocation

The ICAO 24-bit address A66C3D 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
N5127U - 26 2026-07-12

Recent flights last 26

DateFlightRouteTakeoffLandingDuration
2026-07-12 N5127U - Jul 12, 21:45 UTCJul 12, 21:55 UTC10m
2026-07-12 N5127U - Jul 12, 20:01 UTCJul 12, 20:10 UTC10m
2026-07-12 N5127U - Jul 12, 03:05 UTCJul 12, 03:15 UTC10m
2026-07-11 N5127U - Jul 11, 20:05 UTCJul 11, 20:35 UTC30m
2026-07-07 N5127U - Jul 7, 16:00 UTCJul 7, 16:40 UTC40m
2026-07-06 N5127U - Jul 6, 23:05 UTCJul 6, 23:20 UTC15m
2026-07-06 N5127U - Jul 6, 21:05 UTCJul 6, 21:20 UTC15m
2026-07-06 N5127U - Jul 6, 15:05 UTCJul 6, 15:40 UTC35m
2026-07-03 N5127U - Jul 3, 19:05 UTCJul 3, 19:15 UTC10m
2026-07-03 N5127U - Jul 3, 07:10 UTCJul 3, 07:20 UTC10m
2026-07-02 N5127U - Jul 2, 22:10 UTCJul 2, 22:20 UTC10m
2026-06-30 N5127U - Jun 30, 19:25 UTCJun 30, 19:35 UTC10m
2026-06-30 N5127U - Jun 30, 15:35 UTCJun 30, 15:45 UTC10m
2026-06-28 N5127U - Jun 28, 17:10 UTCJun 28, 17:44 UTC35m
2026-06-27 N5127U - Jun 27, 23:14 UTCJun 27, 23:29 UTC15m
2026-06-15 N5127U BYW → LPS Jun 15, 01:25 UTCJun 15, 02:04 UTC40m
2026-06-14 N5127U - Jun 14, 22:15 UTCJun 14, 22:45 UTC30m
2026-06-14 N5127U WDN → LPS Jun 14, 15:35 UTCJun 14, 15:45 UTC10m
2026-06-14 N5127U - Jun 14, 14:45 UTCJun 14, 14:55 UTC10m
2026-06-14 N5127U CWS → LPS Jun 14, 04:45 UTCJun 14, 05:05 UTC20m
2026-06-01 N5127U - Jun 1, 23:30 UTCJun 1, 23:40 UTC10m
2026-06-01 N5127U - Jun 1, 19:30 UTCJun 1, 19:40 UTC10m
2026-05-31 N5127U - May 31, 22:10 UTCMay 31, 22:20 UTC10m
2026-05-31 N5127U - May 31, 17:00 UTCMay 31, 17:10 UTC10m
2026-05-17 N5127U - May 17, 20:25 UTCMay 17, 20:35 UTC10m
2026-05-17 N5127U - May 17, 17:35 UTCMay 17, 17:45 UTC10m

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 N5127U page for operator, model, and routing details .

Mode-S A66C3D frequently asked

What is Mode-S code A66C3D?
A66C3D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N5127U.
Where is Mode-S A66C3D registered?
Mode-S code A66C3D 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 A66C3D broadcasting right now?
No active broadcast right now. Last signal was 13d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A66C3D, octal 51466075, decimal 10,906,685.
What flights does A66C3D operate?
Mode-S A66C3D has broadcast 1 distinct callsign, including N5127U.