Apparatus

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sensors Mode-S transponder

A143E9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N1806U · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
A143E9
Octal
50241751
Decimal
10,568,681
Country
US
Tail
N1806U
Type
B38M
No current signal · last broadcast Jul 26, 21:15 UTC
Flights observed
596
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:15 UTC

Last known position

Most recent position reported by Mode-S A143E9.

Country allocation

The ICAO 24-bit address A143E9 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
SWA2138 - 9 2026-07-09
SWA4109 - 6 2026-06-18
SWA317 Southwest Airlines 5 2026-07-21
SWA2171 - 5 2026-07-10
SWA1913 - 5 2026-07-17
SWA3465 Southwest Airlines 4 2026-04-29
SWA308 Southwest Airlines 4 2026-06-16
SWA2754 Southwest Airlines 4 2026-05-23
SWA2646 - 4 2026-07-20
SWA939 Southwest Airlines 3 2026-05-20
SWA8510 Southwest Airlines 3 2026-05-24
SWA817 Southwest Airlines 3 2026-06-09
SWA744 Southwest Airlines 3 2026-04-23
SWA46 Southwest Airlines 3 2026-05-15
SWA4470 Southwest Airlines 3 2026-07-19
SWA4133 Southwest Airlines 3 2026-05-06
SWA4064 Southwest Airlines 3 2026-06-18
SWA3960 - 3 2026-07-18
SWA3930 Southwest Airlines 3 2026-05-02
SWA3895 Southwest Airlines 3 2026-04-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA3508 MSY → MCO Jul 26, 20:05 UTCJul 26, 21:10 UTC1h 5m
2026-07-26 SWA3508 MSY → MCO Jul 26, 16:35 UTCJul 26, 18:25 UTC1h 50m
2026-07-26 SWA3144 PVD → MDW Jul 26, 13:05 UTCJul 26, 14:55 UTC1h 50m
2026-07-26 SWA2799 DEN → AMA Jul 26, 00:20 UTCJul 26, 03:50 UTC3h 30m
2026-07-25 SWA1789 MDW → MHT Jul 25, 19:20 UTCJul 25, 22:55 UTC3h 35m
2026-07-25 SWA1789 MDW → MHT Jul 25, 19:16 UTCJul 25, 22:50 UTC3h 34m
2026-07-25 SWA4958 LGA → BNA Jul 25, 17:15 UTCJul 25, 18:15 UTC1h 0m
2026-07-25 SWA4958 LGA → BNA Jul 25, 17:14 UTCJul 25, 18:12 UTC58m
2026-07-25 SWA713 OAK → BUR Jul 25, 15:10 UTCJul 25, 16:05 UTC55m
2026-07-25 SWA130 MDW → MCO Jul 25, 12:50 UTCJul 25, 14:00 UTC1h 10m
2026-07-25 SWA1916 MDW → MSY Jul 25, 06:35 UTCJul 25, 08:05 UTC1h 30m
2026-07-24 SWA1916 MDW → MSY Jul 24, 23:30 UTCJul 25, 04:25 UTC4h 55m
2026-07-24 SWA1865 AUS → MIA Jul 24, 16:10 UTCJul 24, 21:40 UTC5h 30m
2026-07-24 SWA4806 LAS → MCI Jul 24, 12:55 UTCJul 24, 14:05 UTC1h 10m
2026-07-24 SWA4806 LAS → MCI Jul 24, 12:50 UTCJul 24, 14:03 UTC1h 13m
2026-07-24 SWA1696 BWI → BOS Jul 24, 05:10 UTCJul 24, 06:55 UTC1h 45m
2026-07-24 SWA4151 MCO → BWI Jul 24, 01:50 UTCJul 24, 03:45 UTC1h 55m
2026-07-23 SWA1938 SJC → AUS Jul 23, 18:25 UTCJul 23, 23:20 UTC4h 55m
2026-07-23 SWA2166 PVD → BWI Jul 23, 16:10 UTCJul 23, 16:35 UTC25m
2026-07-22 SWA4452 LGA → BNA Jul 22, 16:40 UTCJul 22, 17:40 UTC1h 0m
2026-07-22 SWA4452 LGA → BNA Jul 22, 16:39 UTCJul 22, 22:24 UTC5h 45m
2026-07-22 SWA2970 - Jul 22, 13:50 UTCJul 22, 14:45 UTC55m
2026-07-22 SWA3653 - Jul 22, 04:20 UTCJul 22, 05:25 UTC1h 5m
2026-07-22 SWA3653 SFO → SAN Jul 22, 04:16 UTCJul 22, 05:26 UTC1h 10m
2026-07-21 SWA1101 BWI → SFO Jul 21, 21:55 UTCJul 22, 03:20 UTC5h 25m
2026-07-21 SWA1608 CUN → BWI Jul 21, 16:50 UTCJul 21, 20:00 UTC3h 10m
2026-07-21 SWA317 HOU → CUN Jul 21, 13:45 UTCJul 21, 15:35 UTC1h 50m
2026-07-21 SWA301 SJC → LAS Jul 21, 11:25 UTCJul 21, 11:55 UTC30m
2026-07-21 SWA1515 SAN → AUS Jul 21, 03:30 UTCJul 21, 04:00 UTC30m
2026-07-21 SWA1515 SAN → AUS Jul 21, 03:25 UTCJul 21, 03:57 UTC32m
2026-07-20 SWA3218 SAN → AUS Jul 20, 23:15 UTCJul 21, 01:55 UTC2h 39m
2026-07-20 SWA626 SJC → SEA Jul 20, 20:20 UTCJul 20, 22:05 UTC1h 45m
2026-07-20 SWA3245 OAK → DAL Jul 20, 17:45 UTCJul 20, 19:05 UTC1h 20m
2026-07-20 SWA3245 OAK → DAL Jul 20, 17:40 UTCJul 20, 19:00 UTC1h 20m
2026-07-20 SWA1498 SAN → SJC Jul 20, 13:40 UTCJul 20, 16:30 UTC2h 50m
2026-07-20 SWA173 CVG → MDW Jul 20, 07:10 UTCJul 20, 11:55 UTC4h 45m
2026-07-20 SWA2646 - Jul 20, 05:35 UTCJul 20, 05:50 UTC15m
2026-07-20 SWA2646 DEN → ANC Jul 20, 00:35 UTCJul 20, 05:50 UTC5h 15m
2026-07-20 SWA2646 - Jul 20, 00:35 UTCJul 20, 05:20 UTC4h 45m
2026-07-19 SWA2769 SJC → AUS Jul 19, 21:05 UTCJul 19, 23:00 UTC1h 55m
2026-07-19 SWA4470 DAL → SJC Jul 19, 18:40 UTCJul 19, 19:40 UTC1h 0m
2026-07-19 SWA4470 DAL → SJC Jul 19, 18:35 UTCJul 19, 19:36 UTC1h 1m
2026-07-19 SWA4470 DAL → SJC Jul 19, 15:10 UTCJul 19, 17:25 UTC2h 15m
2026-07-19 SWA2858 OGG → LAS Jul 19, 10:40 UTCJul 19, 13:30 UTC2h 50m
2026-07-19 SWA335 LAX → SJC Jul 19, 01:40 UTCJul 19, 03:10 UTC1h 30m
2026-07-18 SWA3960 - Jul 18, 22:55 UTCJul 19, 00:35 UTC1h 40m
2026-07-18 SWA3960 MCI → ATL Jul 18, 22:55 UTCJul 19, 00:29 UTC1h 34m
2026-07-18 SWA1702 - Jul 18, 20:45 UTCJul 18, 21:45 UTC1h 0m
2026-07-18 SWA1702 MKE → MCI Jul 18, 20:44 UTCJul 18, 21:46 UTC1h 2m
2026-07-18 SWA4104 RSW → IND Jul 18, 16:45 UTCJul 18, 19:45 UTC3h 0m

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 N1806U page for operator, model, and routing details .

Mode-S A143E9 frequently asked

What is Mode-S code A143E9?
A143E9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N1806U.
Where is Mode-S A143E9 registered?
Mode-S code A143E9 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 A143E9 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:15 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A143E9, octal 50241751, decimal 10,568,681.
What flights does A143E9 operate?
Mode-S A143E9 has broadcast 20 distinct callsigns, including SWA2138, SWA4109, SWA317, SWA2171, SWA1913.