Apparatus

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sensors Mode-S transponder

AC3731

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N8865L · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
AC3731
Octal
53033461
Decimal
11,286,321
Country
US
Tail
N8865L
Type
B38M
Broadcasting now · callsign SWA3366 · 37,000 ft
Flights observed
682
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:15 UTC

Current position

AC3731 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AC3731 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
SWA995 Southwest Airlines 4 2026-04-15
SWA875 Southwest Airlines 4 2026-06-09
SWA4220 - 4 2026-07-10
SWA4195 - 4 2026-07-05
SWA3004 - 4 2026-07-01
SWA1030 - 4 2026-07-19
SWA963 Southwest Airlines 3 2026-06-09
SWA752 Southwest Airlines 3 2026-05-15
SWA555 - 3 2026-04-13
SWA4831 Southwest Airlines 3 2026-07-26
SWA4698 - 3 2026-07-09
SWA4376 - 3 2026-06-27
SWA4113 - 3 2026-06-27
SWA398 Southwest Airlines 3 2026-05-28
SWA3635 - 3 2026-04-13
SWA3514 Southwest Airlines 3 2026-05-17
SWA3296 Southwest Airlines 3 2026-05-19
SWA3038 Southwest Airlines 3 2026-06-15
SWA295 - 3 2026-07-13
SWA2874 Southwest Airlines 3 2026-05-10

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA4138 PVD → BWI Jul 26, 21:35 UTCJul 26, 22:15 UTC40m
2026-07-26 SWA1771 SEA → SJC Jul 26, 17:20 UTCJul 26, 19:55 UTC2h 35m
2026-07-26 SWA1771 SEA → SJC Jul 26, 15:15 UTCJul 26, 16:05 UTC50m
2026-07-26 SWA3665 MCO → ALB Jul 26, 11:25 UTCJul 26, 14:15 UTC2h 50m
2026-07-26 SWA4831 MEM → DEN Jul 26, 00:05 UTCJul 26, 02:10 UTC2h 5m
2026-07-26 SWA4831 MEM → DEN Jul 26, 00:01 UTCJul 26, 02:05 UTC2h 4m
2026-07-25 SWA2003 OAK → ONT Jul 25, 21:40 UTCJul 25, 22:40 UTC1h 0m
2026-07-25 SWA2003 OAK → ONT Jul 25, 21:35 UTCJul 25, 22:41 UTC1h 6m
2026-07-25 SWA3553 AUS → DAL Jul 25, 18:05 UTCJul 25, 20:15 UTC2h 10m
2026-07-25 SWA3553 AUS → DAL Jul 25, 18:00 UTCJul 25, 20:13 UTC2h 13m
2026-07-25 SWA1975 MDW → MCO Jul 25, 04:50 UTCJul 25, 06:50 UTC2h 0m
2026-07-25 SWA534 MCO → MCI Jul 25, 02:00 UTCJul 25, 03:40 UTC1h 40m
2026-07-24 SWA2112 SJC → SAN Jul 24, 21:10 UTCJul 25, 00:20 UTC3h 10m
2026-07-24 SWA4696 SJC → HOU Jul 24, 14:20 UTCJul 24, 18:25 UTC4h 5m
2026-07-24 SWA984 BWI → MCO Jul 24, 10:55 UTCJul 24, 12:45 UTC1h 50m
2026-07-23 SWA4669 PHX → OAK Jul 23, 23:50 UTCJul 24, 02:25 UTC2h 35m
2026-07-23 SWA1124 BOS → MDW Jul 23, 20:40 UTCJul 23, 22:40 UTC2h 0m
2026-07-23 SWA1032 ATL → DAL Jul 23, 17:35 UTCJul 23, 19:25 UTC1h 50m
2026-07-23 SWA1032 ATL → DAL Jul 23, 17:33 UTCJul 23, 19:22 UTC1h 49m
2026-07-23 SWA4196 MCO → DAL Jul 23, 15:05 UTCJul 23, 16:15 UTC1h 10m
2026-07-23 SWA1012 MKE → CUN Jul 23, 12:05 UTCJul 23, 14:00 UTC1h 55m
2026-07-23 SWA1012 MKE → CUN Jul 23, 12:02 UTCJul 23, 13:55 UTC1h 53m
2026-07-23 SWA3183 DAL → SAT Jul 23, 10:20 UTCJul 23, 10:55 UTC35m
2026-07-23 SWA1040 TPA → PVD Jul 23, 02:25 UTCJul 23, 03:05 UTC40m
2026-07-22 SWA1040 TPA → PVD Jul 22, 22:20 UTCJul 23, 01:05 UTC2h 45m
2026-07-22 SWA202 OAK → LAX Jul 22, 18:05 UTCJul 22, 20:40 UTC2h 35m
2026-07-22 SWA257 RNO → LAS Jul 22, 15:40 UTCJul 22, 16:50 UTC1h 10m
2026-07-22 SWA2327 LAS → OAK Jul 22, 13:25 UTCJul 22, 14:10 UTC45m
2026-07-22 SWA2327 LAS → OAK Jul 22, 13:20 UTCJul 22, 14:08 UTC48m
2026-07-22 SWA3396 BWI → MCI Jul 22, 01:15 UTCJul 22, 04:40 UTC3h 25m
2026-07-21 SWA3212 RSW → MDW Jul 21, 22:30 UTCJul 21, 23:35 UTC1h 5m
2026-07-21 SWA527 - Jul 21, 20:05 UTCJul 21, 21:05 UTC1h 0m
2026-07-21 SWA991 MDW → CLE Jul 21, 14:20 UTCJul 21, 19:00 UTC4h 40m
2026-07-21 SWA2864 MSP → BWI Jul 21, 10:50 UTCJul 21, 12:45 UTC1h 55m
2026-07-21 SWA4880 ATL → STL Jul 21, 04:05 UTCJul 21, 05:20 UTC1h 15m
2026-07-21 SWA4880 ATL → STL Jul 21, 04:04 UTCJul 21, 05:17 UTC1h 13m
2026-07-21 SWA3236 MCO → STL Jul 21, 01:00 UTCJul 21, 03:10 UTC2h 10m
2026-07-20 SWA3948 LGB → SJC Jul 20, 21:45 UTCJul 20, 23:40 UTC1h 55m
2026-07-20 SWA3948 LGB → SJC Jul 20, 21:43 UTCJul 20, 23:34 UTC1h 52m
2026-07-20 SWA2902 DEN → IAD Jul 20, 19:05 UTCJul 20, 19:50 UTC45m
2026-07-20 SWA2902 DEN → IAD Jul 20, 19:03 UTCJul 20, 19:49 UTC46m
2026-07-20 SWA1357 OAK → LAX Jul 20, 16:05 UTCJul 20, 18:00 UTC1h 55m
2026-07-20 SWA1357 OAK → LAX Jul 20, 12:15 UTCJul 20, 14:20 UTC2h 5m
2026-07-20 SWA486 MDW → LGA Jul 20, 06:40 UTCJul 20, 08:10 UTC1h 30m
2026-07-20 SWA662 DEN → MSP Jul 20, 02:00 UTCJul 20, 05:45 UTC3h 45m
2026-07-19 SWA1030 DAL → BNA Jul 19, 22:25 UTCJul 19, 23:55 UTC1h 30m
2026-07-19 SWA4466 ATL → BWI Jul 19, 19:35 UTCJul 19, 21:15 UTC1h 40m
2026-07-19 SWA4222 BWI → LAS Jul 19, 14:55 UTCJul 19, 18:10 UTC3h 15m
2026-07-19 SWA4222 BWI → LAS Jul 19, 14:55 UTCJul 19, 18:00 UTC3h 5m
2026-07-19 SWA2578 LAS → PHX Jul 19, 11:45 UTCJul 19, 13:50 UTC2h 5m

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 N8865L page for operator, model, and routing details .

Mode-S AC3731 frequently asked

What is Mode-S code AC3731?
AC3731 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N8865L.
Where is Mode-S AC3731 registered?
Mode-S code AC3731 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 AC3731 broadcasting right now?
Yes. Mode-S AC3731 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC3731, octal 53033461, decimal 11,286,321.
What flights does AC3731 operate?
Mode-S AC3731 has broadcast 20 distinct callsigns, including SWA995, SWA875, SWA4220, SWA4195, SWA3004.