Apparatus

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sensors Mode-S transponder

A1A7BF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N20559 · CESSNA 172 Skyhawk · operated by WINGS OVER TEXAS HOLDINGS LLC

Hex
A1A7BF
Octal
50323677
Decimal
10,594,239
Country
US
Tail
N20559
Type
C172
No current signal · last broadcast 5d ago
Flights observed
110
Distinct callsigns
1
Country
US
Last broadcast
5d ago

Last known position

Most recent position reported by Mode-S A1A7BF.

Country allocation

The ICAO 24-bit address A1A7BF 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
N20559 - 110 2026-07-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-08 N20559 - Jul 8, 22:05 UTCJul 8, 22:55 UTC50m
2026-07-08 N20559 - Jul 8, 17:10 UTCJul 8, 18:00 UTC50m
2026-07-08 N20559 - Jul 8, 13:55 UTCJul 8, 15:55 UTC2h 0m
2026-07-07 N20559 - Jul 7, 13:55 UTCJul 7, 15:20 UTC1h 25m
2026-07-04 N20559 - Jul 4, 13:55 UTCJul 4, 14:50 UTC55m
2026-07-02 N20559 - Jul 2, 11:15 UTCJul 2, 12:25 UTC1h 10m
2026-07-01 N20559 - Jul 1, 15:50 UTCJul 1, 17:15 UTC1h 25m
2026-06-30 N20559 - Jun 30, 19:50 UTCJun 30, 20:40 UTC50m
2026-06-30 N20559 - Jun 30, 17:05 UTCJun 30, 18:05 UTC1h 0m
2026-06-30 N20559 - Jun 30, 14:30 UTCJun 30, 15:25 UTC55m
2026-06-29 N20559 - Jun 29, 19:54 UTCJun 29, 20:49 UTC55m
2026-06-29 N20559 - Jun 29, 16:59 UTCJun 29, 18:49 UTC1h 50m
2026-06-26 N20559 - Jun 26, 20:44 UTCJun 26, 21:59 UTC1h 15m
2026-06-25 N20559 - Jun 25, 20:49 UTCJun 25, 22:04 UTC1h 15m
2026-06-25 N20559 - Jun 25, 16:29 UTCJun 25, 17:30 UTC1h 0m
2026-06-25 N20559 - Jun 25, 14:24 UTCJun 25, 14:55 UTC30m
2026-06-25 N20559 - Jun 25, 01:59 UTCJun 25, 03:59 UTC2h 0m
2026-06-24 N20559 - Jun 24, 22:04 UTCJun 24, 23:59 UTC1h 55m
2026-06-24 N20559 - Jun 24, 20:09 UTCJun 24, 21:09 UTC1h 0m
2026-06-24 N20559 - Jun 24, 14:09 UTCJun 24, 15:09 UTC1h 0m
2026-06-24 N20559 - Jun 24, 11:24 UTCJun 24, 12:40 UTC1h 15m
2026-06-23 N20559 - Jun 23, 19:39 UTCJun 23, 20:24 UTC45m
2026-06-20 N20559 - Jun 20, 22:39 UTCJun 20, 23:59 UTC1h 20m
2026-06-17 N20559 - Jun 17, 17:05 UTCJun 17, 17:45 UTC40m
2026-06-17 N20559 - Jun 17, 01:15 UTCJun 17, 02:35 UTC1h 20m
2026-06-16 N20559 - Jun 16, 22:15 UTCJun 16, 23:40 UTC1h 25m
2026-06-16 N20559 - Jun 16, 17:30 UTCJun 16, 17:55 UTC25m
2026-06-16 N20559 - Jun 16, 16:25 UTCJun 16, 16:39 UTC15m
2026-06-16 N20559 - Jun 16, 12:45 UTCJun 16, 13:44 UTC1h 0m
2026-06-16 N20559 - Jun 16, 11:45 UTCJun 16, 12:10 UTC25m
2026-06-14 N20559 - Jun 14, 18:05 UTCJun 14, 19:05 UTC1h 0m
2026-06-14 N20559 - Jun 14, 14:10 UTCJun 14, 16:50 UTC2h 40m
2026-06-11 N20559 - Jun 11, 14:30 UTCJun 11, 15:20 UTC50m
2026-06-10 N20559 - Jun 10, 13:35 UTCJun 10, 15:10 UTC1h 35m
2026-06-10 N20559 - Jun 10, 00:20 UTCJun 10, 01:45 UTC1h 25m
2026-06-08 N20559 - Jun 8, 17:15 UTCJun 8, 18:55 UTC1h 40m
2026-06-05 N20559 - Jun 5, 17:15 UTCJun 5, 17:40 UTC25m
2026-06-05 N20559 - Jun 5, 15:15 UTCJun 5, 15:25 UTC10m
2026-06-05 N20559 - Jun 5, 14:25 UTCJun 5, 14:35 UTC10m
2026-06-05 N20559 - Jun 5, 00:40 UTCJun 5, 02:05 UTC1h 25m
2026-06-04 N20559 - Jun 4, 22:00 UTCJun 5, 00:05 UTC2h 5m
2026-06-04 N20559 - Jun 4, 18:50 UTCJun 4, 20:05 UTC1h 15m
2026-06-04 N20559 - Jun 4, 14:55 UTCJun 4, 17:25 UTC2h 30m
2026-06-04 N20559 - Jun 4, 01:20 UTCJun 4, 03:10 UTC1h 50m
2026-06-03 N20559 - Jun 3, 22:00 UTCJun 3, 22:40 UTC40m
2026-06-01 N20559 - Jun 1, 13:50 UTCJun 1, 14:25 UTC35m
2026-05-31 N20559 - May 31, 14:10 UTCMay 31, 14:50 UTC40m
2026-05-29 N20559 - May 29, 14:15 UTCMay 29, 16:00 UTC1h 45m
2026-05-28 N20559 - May 28, 14:15 UTCMay 28, 14:45 UTC30m
2026-05-27 N20559 - May 27, 11:55 UTCMay 27, 12:20 UTC25m

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 N20559 page for operator, model, and routing details .

Mode-S A1A7BF frequently asked

What is Mode-S code A1A7BF?
A1A7BF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N20559.
Where is Mode-S A1A7BF registered?
Mode-S code A1A7BF 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 A1A7BF broadcasting right now?
No active broadcast right now. Last signal was 5d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1A7BF, octal 50323677, decimal 10,594,239.
What flights does A1A7BF operate?
Mode-S A1A7BF has broadcast 1 distinct callsign, including N20559.