Apparatus

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sensors Mode-S transponder

A646D4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N503TX · EMBRAER EMB-500 Phenom 100 · operated by STATE OF TEXAS

Hex
A646D4
Octal
51443324
Decimal
10,897,108
Country
US
Tail
N503TX
Type
E50P
No current signal · last broadcast 10h ago
Flights observed
45
Distinct callsigns
1
Country
US
Last broadcast
10h ago

Last known position

Most recent position reported by Mode-S A646D4.

Country allocation

The ICAO 24-bit address A646D4 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
TEXDOT3 - 45 2026-07-21

Recent flights last 45

DateFlightRouteTakeoffLandingDuration
2026-07-21 TEXDOT3 - Jul 21, 17:35 UTCJul 21, 18:25 UTC50m
2026-07-21 TEXDOT3 - Jul 21, 14:55 UTCJul 21, 15:45 UTC50m
2026-07-21 TEXDOT3 - Jul 21, 13:25 UTCJul 21, 13:55 UTC30m
2026-07-19 TEXDOT3 - Jul 19, 02:50 UTCJul 19, 03:20 UTC30m
2026-07-19 TEXDOT3 - Jul 19, 01:25 UTCJul 19, 02:10 UTC45m
2026-07-18 TEXDOT3 - Jul 18, 22:00 UTCJul 18, 22:55 UTC55m
2026-07-18 TEXDOT3 - Jul 18, 20:05 UTCJul 18, 20:45 UTC40m
2026-07-09 TEXDOT3 - Jul 9, 18:40 UTCJul 9, 19:10 UTC30m
2026-07-09 TEXDOT3 - Jul 9, 13:40 UTCJul 9, 14:05 UTC25m
2026-06-25 TEXDOT3 - Jun 25, 14:59 UTCJun 25, 15:59 UTC1h 0m
2026-06-25 TEXDOT3 - Jun 25, 11:44 UTCJun 25, 12:44 UTC1h 0m
2026-06-22 TEXDOT3 - Jun 22, 19:05 UTCJun 22, 19:44 UTC40m
2026-06-22 TEXDOT3 - Jun 22, 13:05 UTCJun 22, 13:39 UTC35m
2026-06-16 TEXDOT3 - Jun 16, 19:50 UTCJun 16, 20:30 UTC40m
2026-06-16 TEXDOT3 AUS → DAL Jun 16, 16:39 UTCJun 16, 17:24 UTC45m
2026-06-11 TEXDOT3 - Jun 11, 01:40 UTCJun 11, 03:20 UTC1h 40m
2026-06-10 TEXDOT3 - Jun 10, 22:00 UTCJun 10, 22:45 UTC45m
2026-06-10 TEXDOT3 - Jun 10, 20:10 UTCJun 10, 20:45 UTC35m
2026-06-08 TEXDOT3 - Jun 8, 21:45 UTCJun 8, 22:15 UTC30m
2026-06-08 TEXDOT3 - Jun 8, 13:00 UTCJun 8, 13:35 UTC35m
2026-05-20 TEXDOT3 - May 20, 17:35 UTCMay 20, 18:40 UTC1h 5m
2026-05-20 TEXDOT3 AUS → OKC May 20, 15:50 UTCMay 20, 16:50 UTC1h 0m
2026-05-18 TEXDOT3 - May 18, 21:55 UTCMay 18, 22:20 UTC25m
2026-05-18 TEXDOT3 - May 18, 20:15 UTCMay 18, 21:05 UTC50m
2026-05-18 TEXDOT3 - May 18, 13:15 UTCMay 18, 14:00 UTC45m
2026-05-18 TEXDOT3 - May 18, 11:45 UTCMay 18, 12:10 UTC25m
2026-05-07 TEXDOT3 - May 7, 21:05 UTCMay 7, 22:30 UTC1h 25m
2026-05-07 TEXDOT3 - May 7, 15:35 UTCMay 7, 17:15 UTC1h 40m
2026-05-05 TEXDOT3 - May 5, 22:40 UTCMay 5, 23:25 UTC45m
2026-05-05 TEXDOT3 AUS → ADS May 5, 21:10 UTCMay 5, 21:50 UTC40m
2026-05-03 TEXDOT3 - May 3, 20:15 UTCMay 3, 20:55 UTC40m
2026-05-03 TEXDOT3 - May 3, 15:45 UTCMay 3, 16:20 UTC35m
2026-04-28 TEXDOT3 - Apr 28, 20:25 UTCApr 28, 21:05 UTC40m
2026-04-28 TEXDOT3 - Apr 28, 19:05 UTCApr 28, 19:35 UTC30m
2026-04-28 TEXDOT3 - Apr 28, 14:55 UTCApr 28, 15:15 UTC20m
2026-04-28 TEXDOT3 AUS → DAL Apr 28, 13:45 UTCApr 28, 14:25 UTC40m
2026-04-23 TEXDOT3 - Apr 23, 20:05 UTCApr 23, 20:45 UTC40m
2026-04-23 TEXDOT3 - Apr 23, 16:10 UTCApr 23, 16:25 UTC15m
2026-04-23 TEXDOT3 - Apr 23, 11:45 UTCApr 23, 12:30 UTC45m
2026-04-20 TEXDOT3 - Apr 20, 23:55 UTCApr 21, 00:35 UTC40m
2026-04-20 TEXDOT3 - Apr 20, 22:10 UTCApr 20, 23:00 UTC50m
2026-04-20 TEXDOT3 - Apr 20, 18:40 UTCApr 20, 19:05 UTC25m
2026-04-20 TEXDOT3 AUS → AUS Apr 20, 18:05 UTCApr 20, 18:10 UTC5m
2026-04-16 TEXDOT3 - Apr 16, 20:20 UTCApr 16, 20:55 UTC35m
2026-04-16 TEXDOT3 - Apr 16, 13:54 UTCApr 16, 14:35 UTC40m

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 N503TX page for operator, model, and routing details .

Mode-S A646D4 frequently asked

What is Mode-S code A646D4?
A646D4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N503TX.
Where is Mode-S A646D4 registered?
Mode-S code A646D4 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 A646D4 broadcasting right now?
No active broadcast right now. Last signal was 10h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A646D4, octal 51443324, decimal 10,897,108.
What flights does A646D4 operate?
Mode-S A646D4 has broadcast 1 distinct callsign, including TEXDOT3.