Apparatus

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sensors Mode-S transponder

A557C3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N443WN · BOEING 737-700 · operated by SOUTHWEST AIRLINES CO

Hex
A557C3
Octal
51253703
Decimal
10,835,907
Country
US
Tail
N443WN
Type
B737
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
612
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A557C3.

Country allocation

The ICAO 24-bit address A557C3 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
SWA3828 - 8 2026-06-30
SWA585 Southwest Airlines 5 2026-06-14
SWA3295 - 5 2026-06-30
SWA1266 Southwest Airlines 5 2026-06-28
SWA1140 Southwest Airlines 5 2026-04-24
SWA711 - 4 2026-06-30
SWA549 Southwest Airlines 4 2026-04-29
SWA4461 Southwest Airlines 4 2026-07-21
SWA406 - 4 2026-06-29
SWA342 - 4 2026-06-18
SWA2990 Southwest Airlines 4 2026-06-03
SWA291 Southwest Airlines 4 2026-06-07
SWA2737 Southwest Airlines 4 2026-05-28
SWA270 - 4 2026-06-27
SWA2414 - 4 2026-07-09
SWA2256 Southwest Airlines 4 2026-07-20
SWA1954 - 4 2026-04-17
SWA165 - 4 2026-07-03
SWA1118 Southwest Airlines 4 2026-04-25
SWA921 - 3 2026-06-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA2915 LAX → MCI Jul 26, 19:10 UTCJul 26, 21:45 UTC2h 35m
2026-07-26 SWA2908 BUR → OAK Jul 26, 16:40 UTCJul 26, 18:15 UTC1h 35m
2026-07-26 SWA2908 BUR → OAK Jul 26, 16:40 UTCJul 26, 18:02 UTC1h 22m
2026-07-26 SWA2857 OAK → SNA Jul 26, 14:20 UTCJul 26, 15:50 UTC1h 30m
2026-07-26 SWA683 DEN → SFO Jul 26, 11:50 UTCJul 26, 13:15 UTC1h 25m
2026-07-26 SWA683 DEN → SFO Jul 26, 11:48 UTCJul 26, 13:09 UTC1h 21m
2026-07-26 SWA3634 SAV → MDW Jul 26, 06:10 UTCJul 26, 10:05 UTC3h 56m
2026-07-25 SWA673 MHT → MCO Jul 25, 23:40 UTCJul 26, 03:45 UTC4h 5m
2026-07-25 SWA673 MHT → MCO Jul 25, 21:05 UTCJul 25, 22:45 UTC1h 40m
2026-07-25 SWA868 PHX → SNA Jul 25, 17:10 UTCJul 25, 19:35 UTC2h 25m
2026-07-25 SWA868 PHX → SNA Jul 25, 15:20 UTCJul 25, 16:10 UTC50m
2026-07-25 SWA2047 BWI → DEN Jul 25, 13:15 UTCJul 25, 14:25 UTC1h 10m
2026-07-25 SWA4821 DEN → MSY Jul 25, 11:15 UTCJul 25, 12:05 UTC50m
2026-07-25 SWA3143 ALB → BWI Jul 25, 05:05 UTCJul 25, 09:30 UTC4h 25m
2026-07-25 SWA271 DAL → LAS Jul 25, 02:40 UTCJul 25, 03:35 UTC55m
2026-07-25 SWA3305 PVD → MCO Jul 25, 00:30 UTCJul 25, 01:50 UTC1h 20m
2026-07-24 SWA3816 LAS → AUS Jul 24, 21:35 UTCJul 24, 23:00 UTC1h 25m
2026-07-24 SWA1435 OGG → SJC Jul 24, 19:35 UTCJul 24, 20:40 UTC1h 5m
2026-07-24 SWA1435 OGG → SJC Jul 24, 15:50 UTCJul 24, 18:15 UTC2h 25m
2026-07-24 SWA1435 OGG → SJC Jul 24, 12:30 UTCJul 24, 14:35 UTC2h 5m
2026-07-24 SWA385 MHT → MDW Jul 24, 10:40 UTCJul 24, 11:05 UTC25m
2026-07-24 SWA2710 STL → BOS Jul 24, 01:35 UTCJul 24, 02:00 UTC25m
2026-07-23 SWA2035 DAL → TUL Jul 23, 22:15 UTCJul 24, 00:15 UTC2h 0m
2026-07-23 SWA2035 DAL → TUL Jul 23, 22:12 UTCJul 24, 00:13 UTC2h 2m
2026-07-23 SWA3606 - Jul 23, 19:05 UTCJul 23, 20:50 UTC1h 45m
2026-07-23 SWA2077 SJU → BWI Jul 23, 16:25 UTCJul 23, 18:10 UTC1h 45m
2026-07-23 SWA2077 SJU → BWI Jul 23, 16:21 UTCJul 23, 18:10 UTC1h 49m
2026-07-23 SWA2355 LAS → HNL Jul 23, 01:15 UTCJul 23, 02:30 UTC1h 15m
2026-07-22 SWA1282 SJC → SAN Jul 22, 22:45 UTCJul 22, 23:25 UTC40m
2026-07-22 SWA4944 HOU → STL Jul 22, 20:25 UTCJul 22, 21:35 UTC1h 10m
2026-07-22 SWA1310 SAN → LAS Jul 22, 17:50 UTCJul 22, 18:50 UTC1h 0m
2026-07-22 SWA4076 LAS → GRR Jul 22, 16:05 UTCJul 22, 16:45 UTC40m
2026-07-22 SWA4076 LAS → GRR Jul 22, 15:56 UTCJul 22, 16:50 UTC54m
2026-07-22 SWA3012 BUR → SMF Jul 22, 14:15 UTCJul 22, 14:50 UTC35m
2026-07-22 SWA1636 HOU → DAL Jul 22, 11:20 UTCJul 22, 11:45 UTC25m
2026-07-22 SWA606 SFO → PHX Jul 22, 01:35 UTCJul 22, 03:30 UTC1h 55m
2026-07-22 SWA606 SFO → PHX Jul 22, 01:32 UTCJul 22, 03:32 UTC2h 0m
2026-07-21 SWA1222 BUR → OAK Jul 21, 23:40 UTCJul 22, 00:10 UTC30m
2026-07-21 SWA1222 BUR → OAK Jul 21, 23:38 UTCJul 22, 00:06 UTC28m
2026-07-21 SWA1983 SJC → SLC Jul 21, 22:25 UTCJul 21, 22:40 UTC15m
2026-07-21 SWA335 LAX → SJC Jul 21, 18:30 UTCJul 21, 20:05 UTC1h 35m
2026-07-21 SWA4555 BUR → AUS Jul 21, 14:25 UTCJul 21, 17:05 UTC2h 40m
2026-07-21 SWA3248 PHX → BUR Jul 21, 07:30 UTCJul 21, 08:35 UTC1h 5m
2026-07-21 SWA4461 LAX → SFO Jul 21, 05:45 UTCJul 21, 06:45 UTC1h 0m
2026-07-21 SWA4461 LAX → SFO Jul 21, 02:40 UTCJul 21, 04:30 UTC1h 50m
2026-07-21 SWA4461 LAX → SFO Jul 21, 00:50 UTCJul 21, 01:45 UTC55m
2026-07-20 SWA4461 LAX → SFO Jul 20, 21:35 UTCJul 20, 23:20 UTC1h 45m
2026-07-20 SWA3495 - Jul 20, 18:35 UTCJul 20, 20:35 UTC2h 0m
2026-07-20 SWA4261 ABQ → DEN Jul 20, 16:30 UTCJul 20, 17:40 UTC1h 10m
2026-07-20 SWA4261 ABQ → DEN Jul 20, 14:15 UTCJul 20, 15:05 UTC50m

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 N443WN page for operator, model, and routing details .

Mode-S A557C3 frequently asked

What is Mode-S code A557C3?
A557C3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N443WN.
Where is Mode-S A557C3 registered?
Mode-S code A557C3 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 A557C3 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A557C3, octal 51253703, decimal 10,835,907.
What flights does A557C3 operate?
Mode-S A557C3 has broadcast 20 distinct callsigns, including SWA3828, SWA585, SWA3295, SWA1266, SWA1140.