sensors Mode-S transponder

A85FB8

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N639FR · AIRBUS A-321neo · operated by BANK OF UTAH TRUSTEE

Hex
A85FB8
Octal
52057670
Decimal
11,034,552
Country
US
Tail
N639FR
Type
A21N
No current signal · last broadcast 22h ago
Flights observed
17
Distinct callsigns
8
Country
US
Last broadcast
22h ago

Last known position

Most recent position reported by Mode-S A85FB8.

Country allocation

The ICAO 24-bit address A85FB8 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 8 distinct

Callsign Airline Flights Last seen
FFT4807 - 4 2026-04-13
FFT2836 - 3 2026-04-13
FFT4974 - 2 2026-04-13
FFT4067 - 2 2026-04-13
FFT2538 - 2 2026-04-13
FFT1450 - 2 2026-04-14
FFT3407 Frontier Airlines 1 2026-04-13
FFT2339 - 1 2026-04-12

Recent flights last 17

DateFlightRouteTakeoffLandingDuration
2026-04-14 FFT1450 - Apr 14, 07:10 UTCApr 14, 08:45 UTC1h 35m
2026-04-14 FFT1450 - Apr 14, 06:30 UTCApr 14, 07:10 UTC40m
2026-04-13 FFT3407 CLT → TPA Apr 13, 21:50 UTCApr 13, 23:05 UTC1h 15m
2026-04-13 FFT4974 - Apr 13, 19:50 UTCApr 13, 20:20 UTC30m
2026-04-13 FFT4974 - Apr 13, 19:10 UTCApr 13, 20:10 UTC1h 0m
2026-04-13 FFT4807 - Apr 13, 16:15 UTCApr 13, 17:25 UTC1h 10m
2026-04-13 FFT4807 - Apr 13, 15:50 UTCApr 13, 17:25 UTC1h 35m
2026-04-13 FFT4807 - Apr 13, 15:11 UTCApr 13, 17:42 UTC2h 31m
2026-04-13 FFT4807 - Apr 13, 15:11 UTCApr 13, 17:20 UTC2h 9m
2026-04-13 FFT2836 - Apr 13, 12:20 UTCApr 13, 13:35 UTC1h 15m
2026-04-13 FFT2836 - Apr 13, 11:55 UTCApr 13, 13:35 UTC1h 40m
2026-04-13 FFT2836 - Apr 13, 11:30 UTCApr 13, 12:15 UTC45m
2026-04-13 FFT4067 - Apr 13, 03:55 UTCApr 13, 04:05 UTC10m
2026-04-13 FFT4067 - Apr 13, 02:00 UTCApr 13, 04:05 UTC2h 5m
2026-04-13 FFT2538 - Apr 13, 00:20 UTCApr 13, 00:50 UTC30m
2026-04-12 FFT2538 - Apr 12, 23:55 UTCApr 13, 00:50 UTC55m
2026-04-12 FFT2339 - Apr 12, 18:50 UTCApr 12, 20:15 UTC1h 25m

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 N639FR page for operator, model, and routing details .

Mode-S A85FB8 frequently asked

What is Mode-S code A85FB8?
A85FB8 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N639FR.
Where is Mode-S A85FB8 registered?
Mode-S code A85FB8 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 A85FB8 broadcasting right now?
No active broadcast right now. Last signal was 22h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A85FB8, octal 52057670, decimal 11,034,552.
What flights does A85FB8 operate?
Mode-S A85FB8 has broadcast 8 distinct callsigns, including FFT4807, FFT2836, FFT4974, FFT4067, FFT2538.