sensors Mode-S transponder

AC5B66

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N8958Q · operated by SOUTHWEST AIRLINES CO

Hex
AC5B66
Octal
53055546
Decimal
11,295,590
Country
US
Tail
N8958Q
Type
B38M
No current signal · last broadcast 1d ago
Flights observed
13
Distinct callsigns
8
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AC5B66.

Country allocation

The ICAO 24-bit address AC5B66 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
SWA3630 - 3 2026-04-13
SWA3285 Southwest Airlines 3 2026-04-13
SWA2054 - 2 2026-04-13
SWA4656 - 1 2026-04-12
SWA3465 - 1 2026-04-13
SWA2756 - 1 2026-04-13
SWA2198 - 1 2026-04-13
SWA2155 - 1 2026-04-13

Recent flights last 13

DateFlightRouteTakeoffLandingDuration
2026-04-13 SWA2198 - Apr 13, 23:23 UTCApr 14, 01:09 UTC1h 46m
2026-04-13 SWA3630 - Apr 13, 21:06 UTCApr 13, 22:17 UTC1h 11m
2026-04-13 SWA3630 - Apr 13, 19:50 UTCApr 13, 20:05 UTC15m
2026-04-13 SWA3630 - Apr 13, 18:00 UTCApr 13, 20:05 UTC2h 5m
2026-04-13 SWA3285 LAS → LBB Apr 13, 16:20 UTCApr 13, 16:45 UTC25m
2026-04-13 SWA3285 LAS → LBB Apr 13, 15:50 UTCApr 13, 16:45 UTC55m
2026-04-13 SWA3285 LAS → LBB Apr 13, 13:06 UTCApr 13, 16:43 UTC3h 37m
2026-04-13 SWA3465 - Apr 13, 10:32 UTCApr 13, 11:44 UTC1h 12m
2026-04-13 SWA2155 BNA → MSP Apr 13, 04:35 UTCApr 13, 06:31 UTC1h 56m
2026-04-13 SWA2054 DEN → BNA Apr 13, 01:26 UTCApr 13, 03:34 UTC2h 8m
2026-04-13 SWA2054 - Apr 13, 00:20 UTCApr 13, 00:25 UTC5m
2026-04-13 SWA2756 - Apr 13, 00:00 UTCApr 13, 00:25 UTC25m
2026-04-12 SWA4656 LAS → SJC Apr 12, 18:20 UTCApr 12, 19:30 UTC1h 10m

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 N8958Q page for operator, model, and routing details .

Mode-S AC5B66 frequently asked

What is Mode-S code AC5B66?
AC5B66 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N8958Q.
Where is Mode-S AC5B66 registered?
Mode-S code AC5B66 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 AC5B66 broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC5B66, octal 53055546, decimal 11,295,590.
What flights does AC5B66 operate?
Mode-S AC5B66 has broadcast 8 distinct callsigns, including SWA3630, SWA3285, SWA2054, SWA4656, SWA3465.