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 18h ago
Flights observed
17
Distinct callsigns
8
Country
US
Last broadcast
18h ago

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 8 distinct

Callsign Airline Flights Last seen
SWA1653 - 4 2026-04-13
SWA1514 - 3 2026-04-13
SWA407 - 2 2026-04-13
SWA2114 Southwest Airlines 2 2026-04-13
SWA1992 - 2 2026-04-13
SWA1547 Southwest Airlines 2 2026-04-12
SWA3468 Southwest Airlines 1 2026-04-13
SWA1335 Southwest Airlines 1 2026-04-14

Recent flights last 17

DateFlightRouteTakeoffLandingDuration
2026-04-14 SWA1335 DAL → LGB Apr 14, 11:00 UTCApr 14, 11:05 UTC5m
2026-04-13 SWA3468 CMH → LAS Apr 13, 21:37 UTCApr 13, 22:54 UTC1h 17m
2026-04-13 SWA407 - Apr 13, 19:50 UTCApr 13, 20:40 UTC50m
2026-04-13 SWA407 - Apr 13, 18:12 UTCApr 13, 20:39 UTC2h 27m
2026-04-13 SWA1653 - Apr 13, 16:15 UTCApr 13, 17:10 UTC55m
2026-04-13 SWA1653 - Apr 13, 15:50 UTCApr 13, 17:10 UTC1h 20m
2026-04-13 SWA1653 - Apr 13, 14:59 UTCApr 13, 17:13 UTC2h 14m
2026-04-13 SWA1653 - Apr 13, 14:56 UTCApr 13, 17:06 UTC2h 10m
2026-04-13 SWA1514 - Apr 13, 12:20 UTCApr 13, 13:45 UTC1h 25m
2026-04-13 SWA1514 - Apr 13, 11:55 UTCApr 13, 13:45 UTC1h 50m
2026-04-13 SWA1514 - Apr 13, 09:30 UTCApr 13, 12:15 UTC2h 45m
2026-04-13 SWA1992 - Apr 13, 03:55 UTCApr 13, 04:20 UTC25m
2026-04-13 SWA1992 - Apr 13, 03:00 UTCApr 13, 04:04 UTC1h 4m
2026-04-13 SWA2114 PDX → SJC Apr 13, 00:20 UTCApr 13, 01:35 UTC1h 15m
2026-04-12 SWA2114 PDX → SJC Apr 12, 23:55 UTCApr 13, 01:35 UTC1h 40m
2026-04-12 SWA1547 PHX → SFO Apr 12, 18:59 UTCApr 12, 19:54 UTC55m
2026-04-12 SWA1547 PHX → SFO Apr 12, 17:15 UTCApr 12, 18:00 UTC45m

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 18h ago.
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 8 distinct callsigns, including SWA1653, SWA1514, SWA407, SWA2114, SWA1992.