Apparatus

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sensors Mode-S transponder

A5EE51

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N481WN · BOEING 737-700 · operated by SOUTHWEST AIRLINES CO

Hex
A5EE51
Octal
51367121
Decimal
10,874,449
Country
US
Tail
N481WN
Type
B737
No current signal · last broadcast 1h ago
Flights observed
557
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A5EE51.

Country allocation

The ICAO 24-bit address A5EE51 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
SWA1676 Southwest Airlines 8 2026-04-30
SWA2137 Southwest Airlines 6 2026-05-23
SWA549 Southwest Airlines 5 2026-04-15
SWA4636 Southwest Airlines 5 2026-05-17
SWA4128 Southwest Airlines 5 2026-04-28
SWA2168 Southwest Airlines 5 2026-05-21
SWA1219 Southwest Airlines 5 2026-05-02
SWA1095 Southwest Airlines 5 2026-05-08
SWA802 - 4 2026-07-08
SWA572 - 4 2026-07-04
SWA522 Southwest Airlines 4 2026-05-13
SWA4355 - 4 2026-07-10
SWA391 - 4 2026-07-01
SWA3546 Southwest Airlines 4 2026-06-03
SWA3410 Southwest Airlines 4 2026-05-24
SWA2210 Southwest Airlines 4 2026-04-25
SWA1547 Southwest Airlines 4 2026-04-24
SWA1532 - 4 2026-06-28
SWA957 Southwest Airlines 3 2026-05-19
SWA738 Southwest Airlines 3 2026-04-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 SWA4100 - Jul 14, 02:35 UTCJul 14, 03:50 UTC1h 15m
2026-07-13 SWA2920 - Jul 13, 23:00 UTCJul 14, 00:50 UTC1h 50m
2026-07-13 SWA2920 MHT → MDW Jul 13, 22:58 UTCJul 14, 00:51 UTC1h 53m
2026-07-13 SWA4736 - Jul 13, 21:10 UTCJul 13, 22:10 UTC1h 0m
2026-07-13 SWA4734 - Jul 13, 19:10 UTCJul 13, 19:55 UTC45m
2026-07-13 SWA4734 BUF → BWI Jul 13, 19:06 UTCJul 13, 19:52 UTC47m
2026-07-13 SWA894 - Jul 13, 17:15 UTCJul 13, 18:15 UTC1h 0m
2026-07-13 SWA894 BWI → BUF Jul 13, 17:14 UTCJul 13, 18:08 UTC54m
2026-07-13 SWA758 - Jul 13, 15:25 UTCJul 13, 16:10 UTC45m
2026-07-13 SWA758 - Jul 13, 13:25 UTCJul 13, 14:30 UTC1h 5m
2026-07-13 SWA2732 - Jul 13, 10:10 UTCJul 13, 12:00 UTC1h 50m
2026-07-13 SWA1668 BWI → MHT Jul 13, 04:35 UTCJul 13, 05:31 UTC55m
2026-07-13 SWA1399 - Jul 13, 01:35 UTCJul 13, 03:45 UTC2h 10m
2026-07-12 SWA2123 - Jul 12, 22:15 UTCJul 13, 00:35 UTC2h 20m
2026-07-12 SWA1440 - Jul 12, 20:10 UTCJul 12, 20:40 UTC30m
2026-07-12 SWA1440 JAX → MCO Jul 12, 20:09 UTCJul 12, 20:36 UTC27m
2026-07-12 SWA1440 - Jul 12, 16:55 UTCJul 12, 19:20 UTC2h 25m
2026-07-12 SWA271 ATL → DCA Jul 12, 14:15 UTCJul 12, 15:35 UTC1h 20m
2026-07-12 SWA271 ATL → DCA Jul 12, 14:15 UTCJul 12, 15:31 UTC1h 17m
2026-07-12 SWA4969 DCA → ATL Jul 12, 11:25 UTCJul 12, 12:50 UTC1h 25m
2026-07-12 SWA4969 DCA → ATL Jul 12, 11:26 UTCJul 12, 12:44 UTC1h 18m
2026-07-11 SWA3907 STL → DCA Jul 11, 21:10 UTCJul 11, 22:50 UTC1h 40m
2026-07-11 SWA3418 ORF → STL Jul 11, 18:20 UTCJul 11, 20:10 UTC1h 50m
2026-07-11 SWA2791 - Jul 11, 15:15 UTCJul 11, 17:20 UTC2h 5m
2026-07-11 SWA489 - Jul 11, 13:15 UTCJul 11, 14:15 UTC1h 0m
2026-07-11 SWA1894 - Jul 11, 10:40 UTCJul 11, 11:15 UTC35m
2026-07-11 SWA1894 GRR → MDW Jul 11, 10:37 UTCJul 11, 11:11 UTC35m
2026-07-11 SWA4113 - Jul 11, 02:50 UTCJul 11, 03:15 UTC25m
2026-07-11 SWA4113 - Jul 11, 02:45 UTCJul 11, 03:10 UTC25m
2026-07-10 SWA4355 - Jul 10, 23:50 UTCJul 11, 01:50 UTC2h 0m
2026-07-10 SWA4355 - Jul 10, 21:45 UTCJul 10, 22:35 UTC50m
2026-07-10 SWA4355 - Jul 10, 18:40 UTCJul 10, 21:00 UTC2h 20m
2026-07-10 SWA4355 - Jul 10, 15:30 UTCJul 10, 17:30 UTC2h 0m
2026-07-10 SWA4493 - Jul 10, 00:35 UTCJul 10, 02:30 UTC1h 55m
2026-07-09 SWA4918 - Jul 9, 20:35 UTCJul 9, 22:20 UTC1h 45m
2026-07-09 SWA3466 RSW → CMH Jul 9, 17:25 UTCJul 9, 19:20 UTC1h 55m
2026-07-09 SWA3466 RSW → CMH Jul 9, 17:24 UTCJul 9, 19:19 UTC1h 55m
2026-07-09 SWA3481 - Jul 9, 14:15 UTCJul 9, 16:35 UTC2h 20m
2026-07-09 SWA3252 - Jul 9, 11:40 UTCJul 9, 13:10 UTC1h 30m
2026-07-09 SWA3252 RIC → MDW Jul 9, 11:37 UTCJul 9, 13:07 UTC1h 30m
2026-07-09 SWA2353 - Jul 9, 03:30 UTCJul 9, 04:00 UTC30m
2026-07-09 SWA2353 BWI → RIC Jul 9, 03:29 UTCJul 9, 03:52 UTC23m
2026-07-08 SWA2854 - Jul 8, 19:35 UTCJul 9, 00:05 UTC4h 30m
2026-07-08 SWA2854 LAX → BWI Jul 8, 19:32 UTCJul 9, 00:03 UTC4h 31m
2026-07-08 SWA4903 OAK → LAX Jul 8, 17:33 UTCJul 8, 18:29 UTC56m
2026-07-08 SWA4903 OAK → LAX Jul 8, 17:35 UTCJul 8, 18:35 UTC1h 0m
2026-07-08 SWA802 - Jul 8, 15:40 UTCJul 8, 16:30 UTC50m
2026-07-08 SWA802 BUR → OAK Jul 8, 15:38 UTCJul 8, 16:29 UTC51m
2026-07-08 SWA4228 - Jul 8, 02:50 UTCJul 8, 03:40 UTC50m
2026-07-07 SWA4779 AUS → SFO Jul 7, 22:25 UTCJul 8, 01:40 UTC3h 15m

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 N481WN page for operator, model, and routing details .

Mode-S A5EE51 frequently asked

What is Mode-S code A5EE51?
A5EE51 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N481WN.
Where is Mode-S A5EE51 registered?
Mode-S code A5EE51 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 A5EE51 broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A5EE51, octal 51367121, decimal 10,874,449.
What flights does A5EE51 operate?
Mode-S A5EE51 has broadcast 20 distinct callsigns, including SWA1676, SWA2137, SWA549, SWA4636, SWA4128.