Apparatus

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sensors Mode-S transponder

A5451A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N439FR · AIRBUS A-320neo · operated by FRONTIER AIRLINES INC.

Hex
A5451A
Octal
51242432
Decimal
10,831,130
Country
US
Tail
N439FR
Type
A20N
Broadcasting now · callsign FFT2996 · 27,450 ft
Flights observed
427
Distinct callsigns
20
Country
US
Last broadcast
15d ago

Current position

A5451A is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A5451A 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
FFT2472 - 9 2026-07-21
FFT4559 - 6 2026-07-15
FFT2677 - 6 2026-06-28
FFT2471 Frontier Airlines 6 2026-07-22
FFT2231 - 6 2026-06-28
FFT3871 - 5 2026-06-28
FFT3330 - 5 2026-07-14
FFT3202 Frontier Airlines 5 2026-07-17
FFT4753 - 4 2026-06-29
FFT3999 - 4 2026-07-20
FFT3278 Frontier Airlines 4 2026-07-21
FFT3224 - 4 2026-07-19
FFT3208 - 4 2026-07-14
FFT2532 - 4 2026-06-29
FFT2526 Frontier Airlines 4 2026-05-31
FFT2343 - 4 2026-07-14
FFT1699 Frontier Airlines 4 2026-06-27
FFT1270 - 4 2026-07-19
FFT1269 - 4 2026-07-03
FFT4402 Frontier Airlines 3 2026-06-25

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 FFT3787 BWI → DFW Jul 26, 18:40 UTCJul 26, 21:15 UTC2h 35m
2026-07-26 FFT3788 DFW → BWI Jul 26, 14:45 UTCJul 26, 17:25 UTC2h 40m
2026-07-26 FFT4017 BOS → PHL Jul 26, 10:55 UTCJul 26, 13:15 UTC2h 20m
2026-07-25 FFT4524 AUS → MCO Jul 25, 22:30 UTCJul 26, 00:45 UTC2h 15m
2026-07-25 FFT4523 MCO → AUS Jul 25, 18:45 UTCJul 25, 20:50 UTC2h 5m
2026-07-25 FFT3941 ISP → MCO Jul 25, 14:45 UTCJul 25, 17:05 UTC2h 20m
2026-07-25 FFT3942 MCO → ISP Jul 25, 11:15 UTCJul 25, 13:30 UTC2h 15m
2026-07-25 FFT2520 DEN → MCO Jul 25, 06:10 UTCJul 25, 09:10 UTC3h 0m
2026-07-25 FFT3311 MCO → DEN Jul 25, 01:00 UTCJul 25, 04:15 UTC3h 15m
2026-07-24 FFT3554 MSY → MCO Jul 24, 21:40 UTCJul 24, 23:10 UTC1h 30m
2026-07-24 FFT1431 MCO → MSY Jul 24, 19:06 UTCJul 24, 20:07 UTC1h 1m
2026-07-24 FFT1431 MCO → MSY Jul 24, 18:55 UTCJul 24, 20:10 UTC1h 15m
2026-07-24 FFT4685 PSE → MCO Jul 24, 16:25 UTCJul 24, 17:10 UTC45m
2026-07-24 FFT4685 PSE → MCO Jul 24, 14:40 UTCJul 24, 14:50 UTC10m
2026-07-24 FFT4686 MCO → PSE Jul 24, 11:00 UTCJul 24, 11:35 UTC35m
2026-07-24 FFT4003 BWI → MCO Jul 24, 02:00 UTCJul 24, 03:40 UTC1h 40m
2026-07-23 FFT4004 MCO → BWI Jul 23, 22:15 UTCJul 24, 00:45 UTC2h 30m
2026-07-23 FFT2758 CMH → MCO Jul 23, 04:55 UTCJul 23, 06:35 UTC1h 40m
2026-07-22 FFT2757 ONT → SFO Jul 22, 23:50 UTCJul 23, 01:50 UTC2h 0m
2026-07-22 FFT2886 DFW → MCO Jul 22, 17:15 UTCJul 22, 19:40 UTC2h 25m
2026-07-22 FFT2471 EWR → DFW Jul 22, 12:10 UTCJul 22, 15:20 UTC3h 10m
2026-07-21 FFT2472 DFW → EWR Jul 21, 13:00 UTCJul 21, 17:00 UTC4h 0m
2026-07-21 FFT3278 SLC → DFW Jul 21, 03:15 UTCJul 21, 05:25 UTC2h 10m
2026-07-21 FFT3278 SLC → DFW Jul 21, 03:16 UTCJul 21, 05:22 UTC2h 6m
2026-07-20 FFT3277 DFW → SLC Jul 20, 23:50 UTCJul 21, 02:00 UTC2h 10m
2026-07-20 FFT3787 BWI → DFW Jul 20, 18:30 UTCJul 20, 21:10 UTC2h 40m
2026-07-20 FFT3788 DFW → BWI Jul 20, 14:35 UTCJul 20, 17:20 UTC2h 45m
2026-07-20 FFT4000 - Jul 20, 08:00 UTCJul 20, 11:10 UTC3h 10m
2026-07-20 FFT3999 DFW → SFO Jul 20, 03:30 UTCJul 20, 06:35 UTC3h 5m
2026-07-20 FFT3999 DFW → SFO Jul 20, 03:05 UTCJul 20, 06:34 UTC3h 29m
2026-07-19 FFT3223 MSP → DFW Jul 19, 22:25 UTCJul 20, 00:15 UTC1h 50m
2026-07-19 FFT3224 - Jul 19, 18:55 UTCJul 19, 21:00 UTC2h 5m
2026-07-19 FFT3224 DFW → MSP Jul 19, 18:56 UTCJul 19, 20:58 UTC2h 2m
2026-07-19 FFT3021 ATL → DFW Jul 19, 15:25 UTCJul 19, 17:10 UTC1h 45m
2026-07-19 FFT1270 DFW → ATL Jul 19, 11:30 UTCJul 19, 13:15 UTC1h 45m
2026-07-19 FFT1270 DFW → ATL Jul 19, 11:34 UTCJul 19, 13:18 UTC1h 44m
2026-07-19 FFT3278 SLC → DFW Jul 19, 05:25 UTCJul 19, 07:35 UTC2h 10m
2026-07-19 FFT3278 SLC → DFW Jul 19, 05:23 UTCJul 19, 07:35 UTC2h 12m
2026-07-19 FFT3277 DFW → SLC Jul 19, 02:00 UTCJul 19, 04:15 UTC2h 15m
2026-07-18 FFT9239 ATL → JAX Jul 18, 22:05 UTCJul 19, 00:40 UTC2h 35m
2026-07-18 FFT9239 ATL → JAX Jul 18, 21:43 UTCJul 19, 00:45 UTC3h 2m
2026-07-18 FFT2472 DFW → IAD Jul 18, 13:15 UTCJul 18, 17:45 UTC4h 30m
2026-07-18 FFT3203 IND → DFW Jul 18, 02:05 UTCJul 18, 03:45 UTC1h 41m
2026-07-17 FFT3202 DFW → IND Jul 17, 23:10 UTCJul 18, 01:00 UTC1h 50m
2026-07-17 FFT2471 EWR → DFW Jul 17, 17:44 UTCJul 17, 20:55 UTC3h 10m
2026-07-17 FFT2472 DFW → EWR Jul 17, 13:10 UTCJul 17, 16:24 UTC3h 15m
2026-07-17 FFT2472 DFW → EWR Jul 17, 13:05 UTCJul 17, 16:19 UTC3h 14m
2026-07-17 FFT1757 CVG → TPA Jul 17, 01:20 UTCJul 17, 03:20 UTC2h 0m
2026-07-16 FFT4280 DFW → CVG Jul 16, 21:40 UTCJul 16, 23:29 UTC1h 50m
2026-07-16 FFT4690 - Jul 16, 15:30 UTCJul 16, 18:05 UTC2h 35m

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 N439FR page for operator, model, and routing details .

Mode-S A5451A frequently asked

What is Mode-S code A5451A?
A5451A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N439FR.
Where is Mode-S A5451A registered?
Mode-S code A5451A 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 A5451A broadcasting right now?
Yes. Mode-S A5451A is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5451A, octal 51242432, decimal 10,831,130.
What flights does A5451A operate?
Mode-S A5451A has broadcast 20 distinct callsigns, including FFT2472, FFT4559, FFT2677, FFT2471, FFT2231.