sensors Mode-S transponder

A143A3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N1804U · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
A143A3
Octal
50241643
Decimal
10,568,611
Country
US
Tail
N1804U
Type
B38M
No current signal · last broadcast 1d ago
Flights observed
12
Distinct callsigns
8
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A143A3.

Country allocation

The ICAO 24-bit address A143A3 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
SWA2633 - 3 2026-04-13
SWA2545 - 2 2026-04-13
SWA1731 - 2 2026-04-13
SWA3699 - 1 2026-04-13
SWA2138 Southwest Airlines 1 2026-04-13
SWA1253 - 1 2026-04-13
SWA1179 - 1 2026-04-13
SWA1045 Southwest Airlines 1 2026-04-12

Recent flights last 12

DateFlightRouteTakeoffLandingDuration
2026-04-13 SWA3699 - Apr 13, 22:37 UTCApr 14, 00:49 UTC2h 12m
2026-04-13 SWA2633 BNA → PBI Apr 13, 19:55 UTCApr 13, 21:40 UTC1h 45m
2026-04-13 SWA2633 - Apr 13, 19:48 UTCApr 13, 21:39 UTC1h 51m
2026-04-13 SWA2633 - Apr 13, 19:48 UTCApr 13, 21:33 UTC1h 45m
2026-04-13 SWA2545 - Apr 13, 16:57 UTCApr 13, 18:42 UTC1h 45m
2026-04-13 SWA2545 - Apr 13, 16:55 UTCApr 13, 18:38 UTC1h 43m
2026-04-13 SWA1253 - Apr 13, 13:12 UTCApr 13, 15:57 UTC2h 45m
2026-04-13 SWA2138 BNA → PHL Apr 13, 11:10 UTCApr 13, 11:45 UTC35m
2026-04-13 SWA1179 - Apr 13, 04:50 UTCApr 13, 05:50 UTC1h 0m
2026-04-13 SWA1731 - Apr 13, 00:20 UTCApr 13, 02:55 UTC2h 35m
2026-04-13 SWA1731 - Apr 13, 00:00 UTCApr 13, 02:55 UTC2h 55m
2026-04-12 SWA1045 SAN → SJC Apr 12, 17:15 UTCApr 12, 18:35 UTC1h 20m

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 N1804U page for operator, model, and routing details .

Mode-S A143A3 frequently asked

What is Mode-S code A143A3?
A143A3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N1804U.
Where is Mode-S A143A3 registered?
Mode-S code A143A3 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 A143A3 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A143A3, octal 50241643, decimal 10,568,611.
What flights does A143A3 operate?
Mode-S A143A3 has broadcast 8 distinct callsigns, including SWA2633, SWA2545, SWA1731, SWA3699, SWA2138.