Apparatus

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sensors Mode-S transponder

A542D7

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N438WN · BOEING 737-700 · operated by SOUTHWEST AIRLINES CO

Hex
A542D7
Octal
51241327
Decimal
10,830,551
Country
US
Tail
N438WN
Type
B737
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
758
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A542D7.

Country allocation

The ICAO 24-bit address A542D7 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
SWA2775 Southwest Airlines 7 2026-05-22
SWA342 - 6 2026-06-23
SWA257 - 6 2026-07-19
SWA971 Southwest Airlines 5 2026-05-20
SWA482 - 5 2026-07-12
SWA3776 Southwest Airlines 5 2026-04-25
SWA2731 Southwest Airlines 5 2026-04-16
SWA267 Southwest Airlines 5 2026-05-30
SWA2286 Southwest Airlines 5 2026-06-09
SWA149 Southwest Airlines 5 2026-06-16
SWA1323 - 5 2026-06-28
SWA1160 Southwest Airlines 5 2026-05-25
SWA105 - 5 2026-07-15
SWA845 - 4 2026-07-21
SWA714 - 4 2026-07-11
SWA4756 - 4 2026-07-14
SWA369 - 4 2026-04-13
SWA3129 - 4 2026-06-26
SWA294 Southwest Airlines 4 2026-07-23
SWA2121 Southwest Airlines 4 2026-06-08

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA3695 DEN → HOU Jul 26, 20:40 UTCJul 26, 21:45 UTC1h 5m
2026-07-26 SWA3468 CMH → LAS Jul 26, 18:30 UTCJul 26, 19:40 UTC1h 10m
2026-07-26 SWA3507 MDW → BOS Jul 26, 16:25 UTCJul 26, 17:30 UTC1h 5m
2026-07-26 SWA477 BNA → RSW Jul 26, 14:10 UTCJul 26, 15:00 UTC50m
2026-07-26 SWA4907 SAT → MSY Jul 26, 01:35 UTCJul 26, 02:35 UTC1h 0m
2026-07-26 SWA4907 SAT → MSY Jul 26, 01:33 UTCJul 26, 02:30 UTC57m
2026-07-25 SWA2350 LAS → FAT Jul 25, 23:35 UTCJul 26, 00:30 UTC55m
2026-07-25 SWA2350 LAS → FAT Jul 25, 21:35 UTCJul 25, 22:35 UTC1h 0m
2026-07-25 SWA2350 LAS → FAT Jul 25, 17:50 UTCJul 25, 20:40 UTC2h 50m
2026-07-25 SWA3749 SMF → LAS Jul 25, 14:10 UTCJul 25, 16:40 UTC2h 30m
2026-07-25 SWA3828 SNA → OAK Jul 25, 02:25 UTCJul 25, 03:40 UTC1h 15m
2026-07-25 SWA3828 SNA → OAK Jul 25, 02:24 UTCJul 25, 03:34 UTC1h 10m
2026-07-24 SWA406 DAL → LAS Jul 24, 22:30 UTCJul 25, 01:35 UTC3h 5m
2026-07-24 SWA406 DAL → LAS Jul 24, 19:15 UTCJul 24, 20:15 UTC1h 0m
2026-07-24 SWA1762 BWI → ALB Jul 24, 16:45 UTCJul 24, 17:55 UTC1h 10m
2026-07-24 SWA4125 SBA → DEN Jul 24, 13:20 UTCJul 24, 15:15 UTC1h 55m
2026-07-24 SWA3842 MDW → MCO Jul 24, 04:25 UTCJul 24, 06:30 UTC2h 5m
2026-07-24 SWA1303 BNA → MSP Jul 24, 01:10 UTCJul 24, 03:15 UTC2h 5m
2026-07-23 SWA1303 BNA → MSP Jul 23, 22:00 UTCJul 23, 22:35 UTC35m
2026-07-23 SWA1303 BNA → MSP Jul 23, 21:55 UTCJul 23, 22:33 UTC38m
2026-07-23 SWA4400 - Jul 23, 20:10 UTCJul 23, 21:10 UTC1h 0m
2026-07-23 SWA4400 HOU → OKC Jul 23, 20:05 UTCJul 23, 21:05 UTC1h 0m
2026-07-23 SWA4468 AUS → PHX Jul 23, 17:05 UTCJul 23, 18:45 UTC1h 40m
2026-07-23 SWA4468 AUS → PHX Jul 23, 17:01 UTCJul 23, 18:44 UTC1h 44m
2026-07-23 SWA411 BNA → MDW Jul 23, 14:05 UTCJul 23, 16:05 UTC2h 0m
2026-07-23 SWA411 BNA → MDW Jul 23, 11:10 UTCJul 23, 12:50 UTC1h 40m
2026-07-23 SWA294 HOU → ELP Jul 23, 02:50 UTCJul 23, 04:55 UTC2h 5m
2026-07-22 SWA294 HOU → ELP Jul 22, 23:40 UTCJul 23, 01:30 UTC1h 50m
2026-07-22 SWA294 HOU → ELP Jul 22, 21:15 UTCJul 22, 22:25 UTC1h 10m
2026-07-22 SWA1063 LAS → OAK Jul 22, 17:40 UTCJul 22, 20:10 UTC2h 30m
2026-07-22 SWA1695 ISP → BWI Jul 22, 15:35 UTCJul 22, 16:00 UTC25m
2026-07-22 SWA4896 HOU → STL Jul 22, 13:20 UTCJul 22, 14:25 UTC1h 5m
2026-07-22 SWA4896 HOU → STL Jul 22, 13:15 UTCJul 22, 14:26 UTC1h 11m
2026-07-22 SWA2424 DEN → MAF Jul 22, 01:45 UTCJul 22, 02:58 UTC1h 13m
2026-07-22 SWA2424 - Jul 22, 01:50 UTCJul 22, 03:00 UTC1h 10m
2026-07-21 SWA1303 BNA → MSP Jul 21, 22:55 UTCJul 22, 00:30 UTC1h 35m
2026-07-21 SWA845 - Jul 21, 20:25 UTCJul 21, 21:35 UTC1h 10m
2026-07-21 SWA845 - Jul 21, 16:20 UTCJul 21, 19:15 UTC2h 55m
2026-07-21 SWA845 BUR → SMF Jul 21, 14:20 UTCJul 21, 15:15 UTC55m
2026-07-21 SWA2163 SJC → LAS Jul 21, 04:20 UTCJul 21, 05:05 UTC45m
2026-07-21 SWA2163 SJC → LAS Jul 21, 04:17 UTCJul 21, 05:00 UTC43m
2026-07-21 SWA794 BUR → OAK Jul 21, 02:41 UTCJul 21, 03:24 UTC43m
2026-07-21 SWA794 BUR → OAK Jul 21, 02:45 UTCJul 21, 03:30 UTC45m
2026-07-21 SWA4977 SJC → LAS Jul 21, 00:55 UTCJul 21, 01:45 UTC50m
2026-07-21 SWA4977 SJC → LAS Jul 21, 00:54 UTCJul 21, 01:51 UTC57m
2026-07-20 SWA805 LAX → SFO Jul 20, 23:20 UTCJul 21, 00:15 UTC54m
2026-07-20 SWA805 LAX → SFO Jul 20, 23:20 UTCJul 21, 00:08 UTC48m
2026-07-20 SWA3037 EUG → SJC Jul 20, 21:45 UTCJul 20, 22:40 UTC55m
2026-07-20 SWA3037 EUG → SJC Jul 20, 19:30 UTCJul 20, 20:20 UTC50m
2026-07-20 SWA3805 OAK → LAS Jul 20, 17:35 UTCJul 20, 18:35 UTC1h 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 N438WN page for operator, model, and routing details .

Mode-S A542D7 frequently asked

What is Mode-S code A542D7?
A542D7 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N438WN.
Where is Mode-S A542D7 registered?
Mode-S code A542D7 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 A542D7 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 A542D7, octal 51241327, decimal 10,830,551.
What flights does A542D7 operate?
Mode-S A542D7 has broadcast 20 distinct callsigns, including SWA2775, SWA342, SWA257, SWA971, SWA482.