sensors Mode-S transponder

A1A709

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N20502 · CESSNA 172 Skyhawk · operated by ATPCE LLC

Hex
A1A709
Octal
50323411
Decimal
10,594,057
Country
US
Tail
N20502
Type
C172
No current signal · last broadcast 1d ago
Flights observed
1
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A1A709.

Country allocation

The ICAO 24-bit address A1A709 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
CXK584 - 1 2026-04-13

Recent flights last 1

DateFlightRouteTakeoffLandingDuration
2026-04-13 CXK584 - Apr 13, 20:45 UTCApr 13, 21:55 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 N20502 page for operator, model, and routing details .

Mode-S A1A709 frequently asked

What is Mode-S code A1A709?
A1A709 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N20502.
Where is Mode-S A1A709 registered?
Mode-S code A1A709 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 A1A709 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1A709, octal 50323411, decimal 10,594,057.
What flights does A1A709 operate?
Mode-S A1A709 has broadcast 1 distinct callsign, including CXK584.