sensors Mode-S transponder

A1A781

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N2054G · CESSNA 182 Skylane · operated by 54G GROUP

Hex
A1A781
Octal
50323601
Decimal
10,594,177
Country
US
Tail
N2054G
Type
C182
No current signal · last broadcast Jul 20, 23:30 UTC
Flights observed
4
Distinct callsigns
1
Country
US
Last broadcast
Jul 20, 23:30 UTC

Last known position

Most recent position reported by Mode-S A1A781.

Country allocation

The ICAO 24-bit address A1A781 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
N2054G - 4 2026-07-20

Recent flights last 4

DateFlightRouteTakeoffLandingDuration
2026-07-20 N2054G CLS → BFI Jul 20, 22:35 UTCJul 20, 23:30 UTC55m
2026-07-20 N2054G - Jul 20, 21:10 UTCJul 20, 21:50 UTC40m
2026-06-24 N2054G - Jun 24, 21:19 UTCJun 24, 21:44 UTC25m
2026-05-11 N2054G - May 11, 21:05 UTCMay 11, 21:25 UTC20m

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 N2054G page for operator, model, and routing details .

Mode-S A1A781 frequently asked

What is Mode-S code A1A781?
A1A781 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N2054G.
Where is Mode-S A1A781 registered?
Mode-S code A1A781 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 A1A781 broadcasting right now?
No active broadcast right now. Last signal was Jul 20, 23:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1A781, octal 50323601, decimal 10,594,177.
What flights does A1A781 operate?
Mode-S A1A781 has broadcast 1 distinct callsign, including N2054G.