sensors Mode-S transponder

AC4CA8

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N8919K · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
AC4CA8
Octal
53046250
Decimal
11,291,816
Country
US
Tail
N8919K
Type
B38M
Broadcasting now · callsign SWA4429 · 20,275 ft
Flights observed
9
Distinct callsigns
6
Country
US
Last broadcast
1d ago

Current position

AC4CA8 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AC4CA8 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 6 distinct

Callsign Airline Flights Last seen
SWA576 Southwest Airlines 3 2026-04-13
SWA3194 - 2 2026-04-13
SWA8502 - 1 2026-04-13
SWA4053 Southwest Airlines 1 2026-04-13
SWA3685 - 1 2026-04-12
SWA344 - 1 2026-04-12

Recent flights last 9

DateFlightRouteTakeoffLandingDuration
2026-04-13 SWA576 LGA → DAL Apr 13, 22:00 UTCApr 13, 23:20 UTC1h 20m
2026-04-13 SWA576 LGA → DAL Apr 13, 20:05 UTCApr 13, 21:05 UTC1h 0m
2026-04-13 SWA576 LGA → DAL Apr 13, 18:00 UTCApr 13, 19:00 UTC1h 0m
2026-04-13 SWA8502 - Apr 13, 16:15 UTCApr 13, 17:05 UTC50m
2026-04-13 SWA4053 AUS → PHX Apr 13, 06:01 UTCApr 13, 09:27 UTC3h 26m
2026-04-13 SWA3194 - Apr 13, 00:20 UTCApr 13, 03:40 UTC3h 20m
2026-04-12 SWA3194 - Apr 12, 23:55 UTCApr 13, 03:40 UTC3h 45m
2026-04-12 SWA3685 - Apr 12, 18:55 UTCApr 12, 21:15 UTC2h 20m
2026-04-12 SWA344 - Apr 12, 16:25 UTCApr 12, 17:35 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 N8919K page for operator, model, and routing details .

Mode-S AC4CA8 frequently asked

What is Mode-S code AC4CA8?
AC4CA8 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N8919K.
Where is Mode-S AC4CA8 registered?
Mode-S code AC4CA8 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 AC4CA8 broadcasting right now?
Yes. Mode-S AC4CA8 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC4CA8, octal 53046250, decimal 11,291,816.
What flights does AC4CA8 operate?
Mode-S AC4CA8 has broadcast 6 distinct callsigns, including SWA576, SWA3194, SWA8502, SWA4053, SWA3685.