Apparatus

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sensors Mode-S transponder

AC668D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N8988S · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
AC668D
Octal
53063215
Decimal
11,298,445
Country
US
Tail
N8988S
Type
B38M
No current signal · last broadcast Jul 26, 21:10 UTC
Flights observed
783
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:10 UTC

Last known position

Most recent position reported by Mode-S AC668D.

Country allocation

The ICAO 24-bit address AC668D 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
SWA1335 Southwest Airlines 8 2026-05-31
SWA3718 - 5 2026-06-19
SWA2391 Southwest Airlines 5 2026-05-11
SWA3979 Southwest Airlines 4 2026-05-15
SWA3853 Southwest Airlines 4 2026-06-08
SWA3610 Southwest Airlines 4 2026-05-21
SWA2627 Southwest Airlines 4 2026-04-27
SWA2229 Southwest Airlines 4 2026-05-15
SWA2127 Southwest Airlines 4 2026-04-16
SWA1653 - 4 2026-04-13
SWA997 Southwest Airlines 3 2026-05-10
SWA947 Southwest Airlines 3 2026-06-04
SWA938 - 3 2026-06-19
SWA852 Southwest Airlines 3 2026-04-24
SWA840 Southwest Airlines 3 2026-04-14
SWA608 - 3 2026-07-01
SWA590 Southwest Airlines 3 2026-06-10
SWA4426 - 3 2026-07-19
SWA430 Southwest Airlines 3 2026-05-16
SWA4299 Southwest Airlines 3 2026-06-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SWA2364 PHX → RDU Jul 26, 17:45 UTCJul 26, 20:35 UTC2h 50m
2026-07-26 SWA3654 SRQ → MDW Jul 26, 13:25 UTCJul 26, 16:30 UTC3h 5m
2026-07-26 SWA2357 SAN → OAK Jul 26, 04:40 UTCJul 26, 06:05 UTC1h 25m
2026-07-26 SWA2357 SAN → OAK Jul 26, 04:35 UTCJul 26, 06:02 UTC1h 27m
2026-07-25 SWA117 SJC → LAS Jul 25, 23:25 UTCJul 26, 03:25 UTC4h 0m
2026-07-25 SWA117 SJC → LAS Jul 25, 23:21 UTCJul 26, 03:23 UTC4h 3m
2026-07-25 SWA117 SJC → LAS Jul 25, 19:35 UTCJul 25, 21:55 UTC2h 20m
2026-07-25 SWA3116 OAK → LAS Jul 25, 17:05 UTCJul 25, 18:05 UTC1h 0m
2026-07-25 SWA3116 OAK → LAS Jul 25, 14:40 UTCJul 25, 16:00 UTC1h 20m
2026-07-25 SWA1321 DAL → LGA Jul 25, 11:50 UTCJul 25, 13:35 UTC1h 45m
2026-07-25 SWA3886 MDW → BWI Jul 25, 06:15 UTCJul 25, 09:50 UTC3h 35m
2026-07-25 SWA2352 BWI → PWM Jul 25, 03:30 UTCJul 25, 04:25 UTC55m
2026-07-25 SWA2352 BWI → PWM Jul 25, 01:45 UTCJul 25, 02:35 UTC50m
2026-07-24 SWA1926 MSP → MDW Jul 24, 23:15 UTCJul 25, 00:30 UTC1h 15m
2026-07-24 SWA1926 MSP → MDW Jul 24, 23:15 UTCJul 25, 00:25 UTC1h 10m
2026-07-24 SWA3518 DCA → CMH Jul 24, 20:50 UTCJul 24, 21:50 UTC1h 0m
2026-07-24 SWA1838 LAS → BUR Jul 24, 17:30 UTCJul 24, 19:35 UTC2h 5m
2026-07-24 SWA1838 LAS → BUR Jul 24, 17:29 UTCJul 24, 19:34 UTC2h 6m
2026-07-24 SWA1532 BNA → MIA Jul 24, 14:08 UTCJul 24, 16:24 UTC2h 16m
2026-07-24 SWA1532 BNA → MIA Jul 24, 14:10 UTCJul 24, 16:25 UTC2h 15m
2026-07-24 SWA3706 SNA → OAK Jul 24, 11:29 UTCJul 24, 12:50 UTC1h 21m
2026-07-24 SWA3706 SNA → OAK Jul 24, 05:30 UTCJul 24, 12:55 UTC7h 25m
2026-07-24 SWA330 LAS → BUR Jul 24, 02:15 UTCJul 24, 04:35 UTC2h 20m
2026-07-23 SWA2183 SFO → SAN Jul 23, 22:45 UTCJul 24, 01:05 UTC2h 20m
2026-07-23 SWA2183 SFO → SAN Jul 23, 22:40 UTCJul 24, 00:54 UTC2h 14m
2026-07-23 SWA2183 SFO → SAN Jul 23, 20:45 UTCJul 23, 21:30 UTC45m
2026-07-23 SWA4648 MDW → MSY Jul 23, 15:50 UTCJul 23, 19:20 UTC3h 30m
2026-07-23 SWA3432 SAN → OAK Jul 23, 12:25 UTCJul 23, 14:00 UTC1h 35m
2026-07-23 SWA3432 SAN → OAK Jul 23, 12:24 UTCJul 23, 13:57 UTC1h 33m
2026-07-23 SWA1692 MDW → SMF Jul 23, 03:47 UTCJul 23, 06:32 UTC2h 45m
2026-07-23 SWA1692 MDW → SMF Jul 23, 03:50 UTCJul 23, 06:35 UTC2h 45m
2026-07-22 SWA939 PHX → AUS Jul 22, 22:30 UTCJul 23, 02:30 UTC4h 0m
2026-07-22 SWA477 BNA → RSW Jul 22, 16:55 UTCJul 22, 18:15 UTC1h 20m
2026-07-22 SWA477 BNA → RSW Jul 22, 16:54 UTCJul 22, 18:10 UTC1h 16m
2026-07-22 SWA1679 BUR → SMF Jul 22, 14:45 UTCJul 22, 15:45 UTC1h 0m
2026-07-22 SWA4784 DEN → PHL Jul 22, 00:10 UTCJul 22, 04:20 UTC4h 10m
2026-07-21 SWA3073 AMA → DAL Jul 21, 20:45 UTCJul 21, 22:15 UTC1h 30m
2026-07-21 SWA2270 SNA → HOU Jul 21, 17:35 UTCJul 21, 19:20 UTC1h 45m
2026-07-21 SWA2270 SNA → HOU Jul 21, 13:20 UTCJul 21, 16:25 UTC3h 5m
2026-07-21 SWA1351 - Jul 21, 07:30 UTCJul 21, 08:10 UTC40m
2026-07-21 SWA1231 SFO → BUR Jul 21, 05:15 UTCJul 21, 06:35 UTC1h 20m
2026-07-21 SWA4786 SJU → AUS Jul 21, 00:45 UTCJul 21, 02:10 UTC1h 25m
2026-07-20 SWA4682 AUS → MTJ Jul 20, 22:10 UTCJul 20, 23:45 UTC1h 35m
2026-07-20 SWA1421 BWI → BDL Jul 20, 19:15 UTCJul 20, 21:05 UTC1h 50m
2026-07-20 SWA1421 BWI → BDL Jul 20, 19:15 UTCJul 20, 20:43 UTC1h 28m
2026-07-20 SWA1518 STL → PHX Jul 20, 16:30 UTCJul 20, 18:05 UTC1h 35m
2026-07-20 SWA4803 MDW → LAX Jul 20, 12:20 UTCJul 20, 14:00 UTC1h 40m
2026-07-20 SWA3830 SAN → OAK Jul 20, 03:45 UTCJul 20, 05:15 UTC1h 30m
2026-07-20 SWA1304 SFO → LAX Jul 20, 00:30 UTCJul 20, 02:00 UTC1h 30m
2026-07-19 SWA1304 SFO → LAX Jul 19, 21:50 UTCJul 19, 23:10 UTC1h 20m

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 N8988S page for operator, model, and routing details .

Mode-S AC668D frequently asked

What is Mode-S code AC668D?
AC668D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N8988S.
Where is Mode-S AC668D registered?
Mode-S code AC668D 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 AC668D broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:10 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC668D, octal 53063215, decimal 11,298,445.
What flights does AC668D operate?
Mode-S AC668D has broadcast 20 distinct callsigns, including SWA1335, SWA3718, SWA2391, SWA3979, SWA3853.