sensors Mode-S transponder

A1A51A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N205FG · CESSNA 172 Skyhawk · operated by INFINITY FLIGHT GROUP LLC

Hex
A1A51A
Octal
50322432
Decimal
10,593,562
Country
US
Tail
N205FG
Type
C172
No current signal · last broadcast 14h ago
Flights observed
9
Distinct callsigns
1
Country
US
Last broadcast
14h ago

Last known position

Most recent position reported by Mode-S A1A51A.

Country allocation

The ICAO 24-bit address A1A51A 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
N205FG - 9 2026-04-14

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-14 N205FG - Apr 14, 10:55 UTCApr 14, 11:05 UTC10m
2026-04-13 N205FG TTN → TTN Apr 13, 16:15 UTCApr 13, 16:25 UTC10m
2026-04-13 N205FG - Apr 13, 15:50 UTCApr 13, 16:25 UTC35m
2026-04-13 N205FG TTN → TTN Apr 13, 14:55 UTCApr 13, 16:15 UTC1h 20m
2026-04-13 N205FG - Apr 13, 04:20 UTCApr 13, 04:30 UTC10m
2026-04-13 N205FG - Apr 13, 03:55 UTCApr 13, 04:30 UTC35m
2026-04-13 N205FG - Apr 13, 00:20 UTCApr 13, 04:15 UTC3h 55m
2026-04-12 N205FG - Apr 12, 23:55 UTCApr 13, 03:50 UTC3h 55m
2026-04-12 N205FG - Apr 12, 19:20 UTCApr 12, 20:15 UTC55m

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 N205FG page for operator, model, and routing details .

Mode-S A1A51A frequently asked

What is Mode-S code A1A51A?
A1A51A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N205FG.
Where is Mode-S A1A51A registered?
Mode-S code A1A51A 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 A1A51A broadcasting right now?
No active broadcast right now. Last signal was 14h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1A51A, octal 50322432, decimal 10,593,562.
What flights does A1A51A operate?
Mode-S A1A51A has broadcast 1 distinct callsign, including N205FG.