Apparatus

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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
No current signal · last broadcast 1h ago
Flights observed
257
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A523AB.

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 20 distinct

Callsign Airline Flights Last seen
FFT3980 Frontier Airlines 11 2026-05-29
FFT2250 Frontier Airlines 6 2026-05-27
FFT4556 Frontier Airlines 5 2026-04-29
FFT4420 Frontier Airlines 5 2026-04-27
FFT1536 Frontier Airlines 5 2026-04-30
FFT4916 Frontier Airlines 4 2026-05-04
FFT4726 Frontier Airlines 4 2026-05-02
FFT4725 Frontier Airlines 4 2026-04-28
FFT2981 Frontier Airlines 4 2026-05-27
FFT2541 Frontier Airlines 4 2026-05-28
FFT239 Frontier Airlines 4 2026-04-27
FFT2265 Frontier Airlines 4 2026-05-04
FFT1886 Frontier Airlines 4 2026-05-26
FFT1016 Frontier Airlines 4 2026-05-28
FFT777 Frontier Airlines 3 2026-05-20
FFT4915 Frontier Airlines 3 2026-05-04
FFT4639 Frontier Airlines 3 2026-05-18
FFT4462 Frontier Airlines 3 2026-05-28
FFT4419 Frontier Airlines 3 2026-04-27
FFT3853 Frontier Airlines 3 2026-04-30

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 FFT2695 BWI → DFW May 29, 23:05 UTCMay 29, 23:20 UTC15m
2026-05-29 FFT3004 CLT → SJU May 29, 18:40 UTCMay 29, 21:45 UTC3h 5m
2026-05-29 FFT3003 SJU → CLT May 29, 13:30 UTCMay 29, 17:15 UTC3h 45m
2026-05-29 FFT3980 TPA → SJU May 29, 03:20 UTCMay 29, 03:35 UTC15m
2026-05-29 FFT3980 TPA → SJU May 29, 01:00 UTCMay 29, 01:50 UTC50m
2026-05-29 FFT3980 TPA → SJU May 29, 01:09 UTCMay 29, 03:29 UTC2h 20m
2026-05-28 FFT2541 SJU → TPA May 28, 20:50 UTCMay 28, 23:25 UTC2h 35m
2026-05-28 FFT1016 PHL → SJU May 28, 19:05 UTCMay 28, 19:20 UTC15m
2026-05-28 FFT1016 PHL → SJU May 28, 16:15 UTCMay 28, 16:45 UTC30m
2026-05-28 FFT1015 SJU → PHL May 28, 10:45 UTCMay 28, 14:20 UTC3h 35m
2026-05-28 FFT4462 PHL → SJU May 28, 00:15 UTCMay 28, 03:30 UTC3h 15m
2026-05-27 FFT1165 PHL → MCO May 27, 19:05 UTCMay 27, 22:45 UTC3h 40m
2026-05-27 FFT2250 ATL → BDL May 27, 16:50 UTCMay 27, 17:10 UTC20m
2026-05-27 FFT2250 ATL → BDL May 27, 14:35 UTCMay 27, 15:10 UTC35m
2026-05-27 FFT2981 SJU → MCO May 27, 10:10 UTCMay 27, 12:45 UTC2h 35m
2026-05-27 FFT1726 PHL → SJU May 27, 04:14 UTCMay 27, 07:25 UTC3h 11m
2026-05-26 FFT2695 BWI → DFW May 26, 23:05 UTCMay 26, 23:19 UTC15m
2026-05-26 FFT1886 RDU → SJU May 26, 21:14 UTCMay 26, 21:34 UTC20m
2026-05-26 FFT1886 RDU → SJU May 26, 18:34 UTCMay 26, 19:10 UTC35m
2026-05-26 FFT1225 SJU → RDU May 26, 13:15 UTCMay 26, 16:20 UTC3h 5m
2026-05-26 FFT3980 TPA → SJU May 26, 03:25 UTCMay 26, 03:40 UTC15m
2026-05-26 FFT3980 TPA → SJU May 26, 01:05 UTCMay 26, 02:00 UTC55m
2026-05-25 FFT2541 SJU → TPA May 25, 20:59 UTCMay 25, 23:40 UTC2h 40m
2026-05-25 FFT1016 PHL → SJU May 25, 18:55 UTCMay 25, 19:20 UTC25m
2026-05-25 FFT1016 PHL → SJU May 25, 16:05 UTCMay 25, 16:35 UTC30m
2026-05-25 FFT1015 SJU → PHL May 25, 10:45 UTCMay 25, 14:20 UTC3h 35m
2026-05-25 FFT4462 PHL → SJU May 25, 00:23 UTCMay 25, 03:30 UTC3h 7m
2026-05-25 FFT4462 PHL → SJU May 25, 00:23 UTCMay 25, 03:25 UTC3h 2m
2026-05-24 FFT1165 PHL → MCO May 24, 18:55 UTCMay 24, 19:15 UTC20m
2026-05-24 FFT1165 PHL → MCO May 24, 19:00 UTCMay 24, 22:30 UTC3h 30m
2026-05-24 FFT2868 MCO → SJU May 24, 16:55 UTCMay 24, 17:15 UTC20m
2026-05-24 FFT2868 MCO → SJU May 24, 14:55 UTCMay 24, 15:25 UTC30m
2026-05-23 FFT1691 BUF → MCO May 23, 23:50 UTCMay 24, 02:05 UTC2h 15m
2026-05-23 FFT1692 MCO → BUF May 23, 20:15 UTCMay 23, 22:25 UTC2h 10m
2026-05-23 FFT3312 DEN → MCO May 23, 15:25 UTCMay 23, 18:35 UTC3h 11m
2026-05-23 FFT3229 IAH → DEN May 23, 12:10 UTCMay 23, 14:10 UTC2h 0m
2026-05-23 FFT2996 DEN → IAH May 23, 03:15 UTCMay 23, 05:15 UTC2h 0m
2026-05-23 FFT4418 ELP → DEN May 23, 00:10 UTCMay 23, 01:35 UTC1h 25m
2026-05-22 FFT2261 DEN → ELP May 22, 21:35 UTCMay 22, 23:00 UTC1h 25m
2026-05-22 FFT2211 DTW → DEN May 22, 17:45 UTCMay 22, 20:20 UTC2h 35m
2026-05-22 FFT3566 DEN → DTW May 22, 13:45 UTCMay 22, 16:25 UTC2h 40m
2026-05-22 FFT3566 DEN → DTW May 22, 13:54 UTCMay 22, 16:21 UTC2h 27m
2026-05-22 FFT4061 MSN → DEN May 22, 01:20 UTCMay 22, 03:35 UTC2h 15m
2026-05-21 FFT1560 DEN → MSN May 21, 22:25 UTCMay 22, 00:15 UTC1h 50m
2026-05-21 FFT4385 CID → DEN May 21, 18:55 UTCMay 21, 20:40 UTC1h 45m
2026-05-21 FFT4386 DEN → CID May 21, 16:25 UTCMay 21, 17:50 UTC1h 25m
2026-05-21 FFT1500 ONT → DEN May 21, 13:05 UTCMay 21, 15:00 UTC1h 55m
2026-05-21 FFT1261 DEN → ONT May 21, 04:45 UTCMay 21, 06:40 UTC1h 55m
2026-05-20 FFT687 DCA → DEN May 20, 19:15 UTCMay 20, 23:05 UTC3h 50m
2026-05-20 FFT686 DEN → PIT May 20, 13:50 UTCMay 20, 16:45 UTC2h 55m

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?
No active broadcast right now. Last signal was 1h ago.
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 20 distinct callsigns, including FFT3980, FFT2250, FFT4556, FFT4420, FFT1536.