Apparatus

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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 Jul 26, 15:15 UTC
Flights observed
652
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 15:15 UTC

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 20 distinct

Callsign Airline Flights Last seen
SWA3783 - 9 2026-07-14
SWA1851 - 8 2026-07-13
SWA2240 - 6 2026-07-08
SWA1919 - 6 2026-07-13
SWA4452 - 5 2026-07-15
SWA3544 - 5 2026-07-14
SWA3094 - 5 2026-06-30
SWA2509 - 5 2026-07-13
SWA2356 - 5 2026-07-15
SWA1913 - 5 2026-06-17
SWA952 Southwest Airlines 4 2026-07-23
SWA708 Southwest Airlines 4 2026-05-27
SWA4335 Southwest Airlines 4 2026-05-13
SWA3263 Southwest Airlines 4 2026-06-03
SWA3096 Southwest Airlines 4 2026-07-01
SWA2172 - 4 2026-07-15
SWA1938 - 4 2026-06-26
SWA1931 - 4 2026-07-01
SWA1914 - 4 2026-07-18
SWA1890 Southwest Airlines 4 2026-04-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA2200 SAN → OAK Jul 26, 14:25 UTCJul 26, 15:15 UTC50m
2026-07-26 SWA3825 BNA → DCA Jul 26, 01:05 UTCJul 26, 05:15 UTC4h 10m
2026-07-25 SWA1715 BOS → DEN Jul 25, 21:45 UTCJul 25, 23:50 UTC2h 5m
2026-07-25 SWA1715 BOS → DEN Jul 25, 21:41 UTCJul 25, 23:45 UTC2h 4m
2026-07-25 SWA4022 DEN → IAD Jul 25, 19:45 UTCJul 25, 20:30 UTC45m
2026-07-25 SWA4022 DEN → IAD Jul 25, 19:43 UTCJul 25, 20:30 UTC47m
2026-07-25 SWA3939 RNO → DEN Jul 25, 16:30 UTCJul 25, 18:50 UTC2h 20m
2026-07-25 SWA1396 PVD → BWI Jul 25, 14:40 UTCJul 25, 15:25 UTC45m
2026-07-25 SWA1396 PVD → BWI Jul 25, 12:10 UTCJul 25, 13:40 UTC1h 30m
2026-07-25 SWA121 MCO → MSY Jul 25, 02:30 UTCJul 25, 04:35 UTC2h 5m
2026-07-24 SWA4706 LGB → SMF Jul 24, 22:25 UTCJul 25, 01:35 UTC3h 10m
2026-07-24 SWA4013 BWI → BOS Jul 24, 17:50 UTCJul 24, 21:00 UTC3h 10m
2026-07-24 SWA4013 BWI → BOS Jul 24, 14:45 UTCJul 24, 15:55 UTC1h 10m
2026-07-24 SWA4498 TUL → PHX Jul 24, 04:15 UTCJul 24, 06:50 UTC2h 35m
2026-07-24 SWA3576 STL → DAL Jul 24, 00:15 UTCJul 24, 02:30 UTC2h 15m
2026-07-23 SWA4951 MDW → MCO Jul 23, 22:10 UTCJul 23, 23:15 UTC1h 5m
2026-07-23 SWA2325 SNA → OAK Jul 23, 17:45 UTCJul 23, 21:10 UTC3h 25m
2026-07-23 SWA2325 SNA → OAK Jul 23, 17:45 UTCJul 23, 21:10 UTC3h 25m
2026-07-23 SWA2325 SNA → OAK Jul 23, 15:30 UTCJul 23, 16:25 UTC55m
2026-07-23 SWA4205 SLC → LAS Jul 23, 12:40 UTCJul 23, 13:40 UTC1h 0m
2026-07-23 SWA952 SEA → STL Jul 23, 02:20 UTCJul 23, 04:45 UTC2h 25m
2026-07-23 SWA952 SEA → STL Jul 23, 02:20 UTCJul 23, 04:39 UTC2h 20m
2026-07-22 SWA4402 SJC → SAN Jul 22, 22:30 UTCJul 23, 00:40 UTC2h 10m
2026-07-22 SWA4537 ORF → DAL Jul 22, 19:25 UTCJul 22, 21:15 UTC1h 50m
2026-07-22 SWA3186 DCA → PVD Jul 22, 15:10 UTCJul 22, 18:05 UTC2h 55m
2026-07-22 SWA3186 DCA → PVD Jul 22, 15:06 UTCJul 22, 18:00 UTC2h 54m
2026-07-22 SWA3586 BWI → PWM Jul 22, 11:10 UTCJul 22, 13:45 UTC2h 35m
2026-07-21 SWA1999 PUJ → MDW Jul 21, 19:55 UTCJul 22, 00:05 UTC4h 10m
2026-07-21 SWA782 SFO → DEN Jul 21, 15:40 UTCJul 21, 16:15 UTC35m
2026-07-21 SWA782 SFO → DEN Jul 21, 15:35 UTCJul 21, 17:45 UTC2h 10m
2026-07-21 SWA4183 OGG → PHX Jul 21, 11:50 UTCJul 21, 13:50 UTC2h 0m
2026-07-21 SWA4203 PHX → MDW Jul 21, 00:55 UTCJul 21, 03:05 UTC2h 10m
2026-07-21 SWA4203 PHX → MDW Jul 21, 00:53 UTCJul 21, 03:11 UTC2h 18m
2026-07-20 SWA4823 - Jul 20, 23:15 UTCJul 21, 00:00 UTC44m
2026-07-20 SWA4823 ELP → PHX Jul 20, 22:55 UTCJul 20, 23:55 UTC1h 0m
2026-07-20 SWA1979 OAK → LAS Jul 20, 20:15 UTCJul 20, 21:20 UTC1h 5m
2026-07-20 SWA2555 TPA → MSY Jul 20, 17:15 UTCJul 20, 18:55 UTC1h 40m
2026-07-20 SWA1584 - Jul 20, 14:50 UTCJul 20, 16:00 UTC1h 10m
2026-07-20 SWA4336 LAS → DEN Jul 20, 05:30 UTCJul 20, 13:35 UTC8h 5m
2026-07-20 SWA102 AUS → LAS Jul 20, 01:59 UTCJul 20, 04:13 UTC2h 15m
2026-07-20 SWA102 AUS → LAS Jul 20, 02:00 UTCJul 20, 04:15 UTC2h 15m
2026-07-19 SWA587 CUN → AUS Jul 19, 22:25 UTCJul 20, 00:25 UTC2h 0m
2026-07-19 SWA169 LAS → CUN Jul 19, 16:20 UTCJul 19, 20:20 UTC4h 0m
2026-07-19 SWA656 PDX → LAS Jul 19, 12:10 UTCJul 19, 14:00 UTC1h 50m
2026-07-19 SWA2852 - Jul 19, 01:35 UTCJul 19, 05:25 UTC3h 50m
2026-07-19 SWA2852 MDW → PDX Jul 19, 01:35 UTCJul 19, 05:21 UTC3h 46m
2026-07-18 SWA954 - Jul 18, 23:15 UTCJul 19, 00:10 UTC55m
2026-07-18 SWA954 MCI → MDW Jul 18, 23:10 UTCJul 19, 00:14 UTC1h 4m
2026-07-18 SWA750 CUN → MCI Jul 18, 18:40 UTCJul 18, 21:20 UTC2h 40m
2026-07-18 SWA1710 OAK → PHX Jul 18, 13:15 UTCJul 18, 17:00 UTC3h 45m

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 Jul 26, 15:15 UTC.
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 20 distinct callsigns, including SWA3783, SWA1851, SWA2240, SWA1919, SWA4452.