sensors Mode-S transponder

A120A1

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N172AF · PILATUS PC-12 · operated by DYNASTY FLIGHT LLC, BEACH SOUTHEAST LLC, BLACK DOG AVIATION LLC, CRISAN JEFFREY, MACLEAN TODD A, BLACK DARREN M

Hex
A120A1
Octal
50220241
Decimal
10,559,649
Country
US
Tail
N172AF
Type
PC12
Photo of N172AF
No current signal · last broadcast 1d ago
Flights observed
3
Distinct callsigns
3
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A120A1.

Country allocation

The ICAO 24-bit address A120A1 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 3 distinct

Callsign Airline Flights Last seen
N172AF - 1 2026-04-12
CNS423 - 1 2026-04-13
CNS2112 - 1 2026-04-13

Recent flights last 3

DateFlightRouteTakeoffLandingDuration
2026-04-13 CNS2112 - Apr 13, 17:05 UTCApr 13, 18:55 UTC1h 50m
2026-04-13 CNS423 TUS → DEN Apr 13, 13:35 UTCApr 13, 15:40 UTC2h 5m
2026-04-12 N172AF - Apr 12, 17:15 UTCApr 12, 17:30 UTC15m

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 N172AF page for operator, model, and routing details .

Mode-S A120A1 frequently asked

What is Mode-S code A120A1?
A120A1 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N172AF.
Where is Mode-S A120A1 registered?
Mode-S code A120A1 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 A120A1 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 A120A1, octal 50220241, decimal 10,559,649.
What flights does A120A1 operate?
Mode-S A120A1 has broadcast 3 distinct callsigns, including N172AF, CNS423, CNS2112.