sensors Mode-S transponder

AC42BF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N8898L · BOEING 737 MAX 8 · operated by SOUTHWEST AIRLINES CO

Hex
AC42BF
Octal
53041277
Decimal
11,289,279
Country
US
Tail
N8898L
Type
B38M
Transponder active on ground
Flights observed
15
Distinct callsigns
7
Country
US
Last broadcast
19h ago

Last known position

Most recent position reported by Mode-S AC42BF.

Country allocation

The ICAO 24-bit address AC42BF 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 7 distinct

Callsign Airline Flights Last seen
SWA2576 - 4 2026-04-13
SWA3129 - 3 2026-04-13
SWA1971 - 3 2026-04-13
SWA3053 Southwest Airlines 2 2026-04-13
SWA3775 Southwest Airlines 1 2026-04-13
SWA3378 - 1 2026-04-14
SWA2320 - 1 2026-04-12

Recent flights last 15

DateFlightRouteTakeoffLandingDuration
2026-04-14 SWA3378 - Apr 14, 06:00 UTCApr 14, 07:05 UTC1h 5m
2026-04-13 SWA3775 DCA → PVD Apr 13, 20:30 UTCApr 13, 22:50 UTC2h 20m
2026-04-13 SWA3129 - Apr 13, 16:15 UTCApr 13, 19:25 UTC3h 10m
2026-04-13 SWA3129 - Apr 13, 15:50 UTCApr 13, 19:25 UTC3h 35m
2026-04-13 SWA3129 - Apr 13, 15:30 UTCApr 13, 16:15 UTC45m
2026-04-13 SWA1971 - Apr 13, 12:20 UTCApr 13, 14:10 UTC1h 50m
2026-04-13 SWA1971 - Apr 13, 11:55 UTCApr 13, 14:10 UTC2h 15m
2026-04-13 SWA1971 - Apr 13, 09:25 UTCApr 13, 12:15 UTC2h 50m
2026-04-13 SWA2576 - Apr 13, 04:20 UTCApr 13, 04:30 UTC10m
2026-04-13 SWA2576 - Apr 13, 03:55 UTCApr 13, 04:30 UTC35m
2026-04-13 SWA2576 - Apr 13, 03:30 UTCApr 13, 04:15 UTC45m
2026-04-13 SWA2576 - Apr 13, 00:53 UTCApr 13, 03:13 UTC2h 20m
2026-04-13 SWA3053 SAN → SFO Apr 13, 00:20 UTCApr 13, 00:35 UTC15m
2026-04-12 SWA3053 SAN → SFO Apr 12, 23:55 UTCApr 13, 00:35 UTC40m
2026-04-12 SWA2320 - Apr 12, 18:03 UTCApr 12, 19:08 UTC1h 5m

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 N8898L page for operator, model, and routing details .

Mode-S AC42BF frequently asked

What is Mode-S code AC42BF?
AC42BF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N8898L.
Where is Mode-S AC42BF registered?
Mode-S code AC42BF 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 AC42BF broadcasting right now?
Mode-S AC42BF is currently broadcasting from the ground.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC42BF, octal 53041277, decimal 11,289,279.
What flights does AC42BF operate?
Mode-S AC42BF has broadcast 7 distinct callsigns, including SWA2576, SWA3129, SWA1971, SWA3053, SWA3775.