sensors Mode-S transponder

A523AB

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N430FR · operated by FRONTIER AIRLINES INC.

Hex
A523AB
Octal
51221653
Decimal
10,822,571
Country
US
Tail
N430FR
Broadcasting now · callsign FFT4405 · 28,275 ft
Flights observed
11
Distinct callsigns
7
Country
US
Last broadcast
17h ago

Current position

A523AB is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A523AB 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 7 distinct

Callsign Airline Flights Last seen
FFT2110 Frontier Airlines 3 2026-04-13
FFT58 - 2 2026-04-13
FFT2291 - 2 2026-04-13
FFT59 - 1 2026-04-13
FFT4196 - 1 2026-04-13
FFT4195 - 1 2026-04-14
FFT2780 - 1 2026-04-12

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-14 FFT4195 - Apr 14, 05:15 UTCApr 14, 06:00 UTC45m
2026-04-13 FFT4196 - Apr 13, 23:15 UTCApr 13, 23:45 UTC30m
2026-04-13 FFT59 - Apr 13, 19:50 UTCApr 13, 21:40 UTC1h 50m
2026-04-13 FFT58 - Apr 13, 16:15 UTCApr 13, 19:50 UTC3h 35m
2026-04-13 FFT58 - Apr 13, 16:10 UTCApr 13, 17:25 UTC1h 15m
2026-04-13 FFT2110 MDW → MIA Apr 13, 12:20 UTCApr 13, 14:20 UTC2h 0m
2026-04-13 FFT2110 MDW → MIA Apr 13, 11:55 UTCApr 13, 14:20 UTC2h 25m
2026-04-13 FFT2110 MDW → MIA Apr 13, 11:35 UTCApr 13, 12:15 UTC40m
2026-04-13 FFT2291 - Apr 13, 00:20 UTCApr 13, 00:40 UTC20m
2026-04-12 FFT2291 - Apr 12, 23:55 UTCApr 13, 00:40 UTC45m
2026-04-12 FFT2780 - Apr 12, 20:05 UTCApr 12, 20:15 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 N430FR page for operator, model, and routing details .

Mode-S A523AB frequently asked

What is Mode-S code A523AB?
A523AB is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N430FR.
Where is Mode-S A523AB registered?
Mode-S code A523AB 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 A523AB broadcasting right now?
Yes. Mode-S A523AB is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A523AB, octal 51221653, decimal 10,822,571.
What flights does A523AB operate?
Mode-S A523AB has broadcast 7 distinct callsigns, including FFT2110, FFT58, FFT2291, FFT59, FFT4196.