Apparatus

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sensors Mode-S transponder

A53F20

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N437WN · BOEING 737-700 · operated by SOUTHWEST AIRLINES CO

Hex
A53F20
Octal
51237440
Decimal
10,829,600
Country
US
Tail
N437WN
Type
B737
No current signal · last broadcast Jul 26, 21:05 UTC
Flights observed
701
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:05 UTC

Last known position

Most recent position reported by Mode-S A53F20.

Country allocation

The ICAO 24-bit address A53F20 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
SWA1396 Southwest Airlines 7 2026-06-11
SWA380 - 6 2026-07-09
SWA3086 Southwest Airlines 6 2026-07-21
SWA2310 - 5 2026-07-10
SWA1840 Southwest Airlines 5 2026-06-12
SWA881 Southwest Airlines 4 2026-06-10
SWA4389 - 4 2026-06-23
SWA3828 - 4 2026-06-26
SWA3151 - 4 2026-06-19
SWA311 Southwest Airlines 4 2026-06-04
SWA2997 Southwest Airlines 4 2026-06-07
SWA2820 - 4 2026-07-11
SWA2624 Southwest Airlines 4 2026-05-17
SWA1901 Southwest Airlines 4 2026-07-21
SWA1642 - 4 2026-06-26
SWA1530 - 4 2026-07-06
SWA1400 - 4 2026-07-14
SWA971 Southwest Airlines 3 2026-05-18
SWA9002 Southwest Airlines 3 2026-06-20
SWA8513 - 3 2026-07-04

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA3768 BWI → TPA Jul 26, 19:00 UTCJul 26, 21:05 UTC2h 5m
2026-07-26 SWA4653 AUS → MCI Jul 26, 15:25 UTCJul 26, 17:55 UTC2h 30m
2026-07-26 SWA4653 AUS → MCI Jul 26, 15:23 UTCJul 26, 17:54 UTC2h 31m
2026-07-26 SWA1442 MCI → DEN Jul 26, 12:05 UTCJul 26, 13:35 UTC1h 30m
2026-07-26 SWA1442 MCI → DEN Jul 26, 12:01 UTCJul 26, 13:36 UTC1h 36m
2026-07-25 SWA3907 PBI → BWI Jul 25, 21:00 UTCJul 25, 22:35 UTC1h 35m
2026-07-25 SWA3907 PBI → BWI Jul 25, 20:59 UTCJul 25, 22:34 UTC1h 35m
2026-07-25 SWA3418 BUR → LAS Jul 25, 18:15 UTCJul 25, 20:05 UTC1h 50m
2026-07-25 SWA2791 OAK → BUR Jul 25, 15:05 UTCJul 25, 17:20 UTC2h 15m
2026-07-25 SWA489 SEA → OAK Jul 25, 13:00 UTCJul 25, 13:55 UTC55m
2026-07-25 SWA489 SEA → OAK Jul 25, 12:57 UTCJul 25, 13:55 UTC58m
2026-07-25 SWA3957 DEN → BNA Jul 25, 03:00 UTCJul 25, 03:45 UTC45m
2026-07-24 SWA4895 SRQ → IND Jul 24, 22:50 UTCJul 25, 01:00 UTC2h 10m
2026-07-24 SWA2804 DCA → MDW Jul 24, 20:00 UTCJul 24, 21:35 UTC1h 35m
2026-07-24 SWA3409 LAS → EUG Jul 24, 16:50 UTCJul 24, 18:50 UTC2h 0m
2026-07-24 SWA4628 OAK → LAS Jul 24, 15:00 UTCJul 24, 15:55 UTC55m
2026-07-24 SWA1899 MDW → DCA Jul 24, 12:40 UTCJul 24, 13:50 UTC1h 10m
2026-07-24 SWA4563 BOI → SMF Jul 24, 02:40 UTCJul 24, 03:25 UTC45m
2026-07-23 SWA1428 SJC → SAN Jul 23, 23:49 UTCJul 24, 01:06 UTC1h 17m
2026-07-23 SWA1428 SJC → SAN Jul 23, 23:50 UTCJul 24, 01:20 UTC1h 30m
2026-07-23 SWA324 STL → DAL Jul 23, 20:10 UTCJul 23, 22:25 UTC2h 15m
2026-07-23 SWA324 STL → DAL Jul 23, 20:07 UTCJul 23, 22:23 UTC2h 17m
2026-07-23 SWA4442 LIH → LAX Jul 23, 17:50 UTCJul 23, 19:10 UTC1h 20m
2026-07-23 SWA4442 LIH → LAX Jul 23, 16:00 UTCJul 23, 16:50 UTC50m
2026-07-23 SWA2458 AUS → DAL Jul 23, 13:25 UTCJul 23, 14:20 UTC55m
2026-07-23 SWA2458 AUS → DAL Jul 23, 13:23 UTCJul 23, 14:17 UTC54m
2026-07-23 SWA857 LAS → OAK Jul 23, 11:40 UTCJul 23, 12:30 UTC50m
2026-07-23 SWA3143 ALB → BWI Jul 23, 05:00 UTCJul 23, 09:25 UTC4h 25m
2026-07-23 SWA2015 OAK → PHX Jul 23, 02:35 UTCJul 23, 03:05 UTC30m
2026-07-23 SWA2404 SAN → OAK Jul 23, 00:35 UTCJul 23, 01:20 UTC45m
2026-07-22 SWA3176 OAK → LAX Jul 22, 22:20 UTCJul 22, 23:15 UTC55m
2026-07-22 SWA1594 PHX → OAK Jul 22, 19:10 UTCJul 22, 21:10 UTC2h 0m
2026-07-22 SWA1594 PHX → OAK Jul 22, 19:08 UTCJul 22, 21:07 UTC1h 59m
2026-07-22 SWA1594 PHX → OAK Jul 22, 16:50 UTCJul 22, 18:10 UTC1h 20m
2026-07-22 SWA1473 LAS → SJC Jul 22, 14:35 UTCJul 22, 15:40 UTC1h 5m
2026-07-22 SWA1473 LAS → SJC Jul 22, 12:25 UTCJul 22, 13:30 UTC1h 5m
2026-07-22 SWA482 BWI → ALB Jul 22, 01:30 UTCJul 22, 02:15 UTC45m
2026-07-21 SWA482 BWI → ALB Jul 21, 23:30 UTCJul 22, 00:30 UTC1h 0m
2026-07-21 SWA482 BWI → ALB Jul 21, 21:00 UTCJul 21, 22:45 UTC1h 45m
2026-07-21 SWA932 MDW → DEN Jul 21, 18:45 UTCJul 21, 19:40 UTC55m
2026-07-21 SWA2621 BUR → OAK Jul 21, 16:40 UTCJul 21, 17:55 UTC1h 15m
2026-07-21 SWA1901 ABQ → SAN Jul 21, 14:30 UTCJul 21, 14:50 UTC20m
2026-07-21 SWA3086 LAS → OAK Jul 21, 00:30 UTCJul 21, 00:50 UTC20m
2026-07-20 SWA3086 LAS → OAK Jul 20, 21:30 UTCJul 20, 23:25 UTC1h 55m
2026-07-20 SWA3086 LAS → OAK Jul 20, 19:20 UTCJul 20, 20:25 UTC1h 5m
2026-07-20 SWA3849 - Jul 20, 17:15 UTCJul 20, 18:10 UTC55m
2026-07-20 SWA3348 - Jul 20, 15:15 UTCJul 20, 16:10 UTC55m
2026-07-20 SWA4145 SFO → PHX Jul 20, 12:30 UTCJul 20, 14:05 UTC1h 35m
2026-07-20 SWA2932 SLC → DEN Jul 20, 05:45 UTCJul 20, 06:40 UTC55m
2026-07-20 SWA2883 HOU → ATL Jul 20, 01:35 UTCJul 20, 03:10 UTC1h 35m

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 N437WN page for operator, model, and routing details .

Mode-S A53F20 frequently asked

What is Mode-S code A53F20?
A53F20 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N437WN.
Where is Mode-S A53F20 registered?
Mode-S code A53F20 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 A53F20 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:05 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A53F20, octal 51237440, decimal 10,829,600.
What flights does A53F20 operate?
Mode-S A53F20 has broadcast 20 distinct callsigns, including SWA1396, SWA380, SWA3086, SWA2310, SWA1840.