sensors Mode-S transponder

AC20A1

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N8803L · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
AC20A1
Octal
53020241
Decimal
11,280,545
Country
US
Tail
N8803L
Type
B38M
Broadcasting now · callsign SWA3435 · 36,000 ft
Flights observed
15
Distinct callsigns
8
Country
US
Last broadcast
17h ago

Current position

AC20A1 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address AC20A1 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
SWA4535 - 3 2026-04-13
SWA3069 - 3 2026-04-13
SWA185 Southwest Airlines 3 2026-04-13
SWA2537 - 2 2026-04-13
SWA510 Southwest Airlines 1 2026-04-14
SWA2652 - 1 2026-04-13
SWA2640 - 1 2026-04-12
SWA254 - 1 2026-04-13

Recent flights last 15

DateFlightRouteTakeoffLandingDuration
2026-04-14 SWA510 BWI → MHT Apr 14, 05:15 UTCApr 14, 05:35 UTC20m
2026-04-13 SWA254 - Apr 13, 20:37 UTCApr 13, 22:50 UTC2h 13m
2026-04-13 SWA2652 BNA → SRQ Apr 13, 18:09 UTCApr 13, 19:41 UTC1h 32m
2026-04-13 SWA4535 - Apr 13, 16:15 UTCApr 13, 16:55 UTC40m
2026-04-13 SWA4535 - Apr 13, 15:50 UTCApr 13, 16:55 UTC1h 5m
2026-04-13 SWA4535 - Apr 13, 15:30 UTCApr 13, 16:15 UTC45m
2026-04-13 SWA185 ATL → LGA Apr 13, 12:20 UTCApr 13, 14:00 UTC1h 40m
2026-04-13 SWA185 ATL → LGA Apr 13, 11:55 UTCApr 13, 14:00 UTC2h 5m
2026-04-13 SWA185 ATL → LGA Apr 13, 11:15 UTCApr 13, 12:15 UTC1h 0m
2026-04-13 SWA3069 - Apr 13, 03:55 UTCApr 13, 04:25 UTC30m
2026-04-13 SWA3069 - Apr 13, 01:00 UTCApr 13, 03:25 UTC2h 25m
2026-04-13 SWA3069 - Apr 13, 01:54 UTCApr 13, 04:24 UTC2h 30m
2026-04-13 SWA2537 - Apr 13, 00:20 UTCApr 13, 00:30 UTC10m
2026-04-12 SWA2537 - Apr 12, 23:55 UTCApr 13, 00:30 UTC35m
2026-04-12 SWA2640 - Apr 12, 18:20 UTCApr 12, 19:33 UTC1h 13m

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 N8803L page for operator, model, and routing details .

Mode-S AC20A1 frequently asked

What is Mode-S code AC20A1?
AC20A1 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N8803L.
Where is Mode-S AC20A1 registered?
Mode-S code AC20A1 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 AC20A1 broadcasting right now?
Yes. Mode-S AC20A1 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC20A1, octal 53020241, decimal 11,280,545.
What flights does AC20A1 operate?
Mode-S AC20A1 has broadcast 8 distinct callsigns, including SWA4535, SWA3069, SWA185, SWA2537, SWA510.