sensors Mode-S transponder

AC71DF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N9002W · operated by SOUTHWEST AIRLINES CO.

Hex
AC71DF
Octal
53070737
Decimal
11,301,343
Country
US
Tail
N9002W
No current signal · last broadcast 13d ago
Flights observed
8
Distinct callsigns
2
Country
US
Last broadcast
13d ago

Last known position

Most recent position reported by Mode-S AC71DF.

Country allocation

The ICAO 24-bit address AC71DF 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 2 distinct

Callsign Airline Flights Last seen
BOE338 - 6 2026-05-11
BOE123 - 2 2026-04-16

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-05-11 BOE338 BFI → BFI May 11, 19:40 UTCMay 11, 21:15 UTC1h 35m
2026-05-08 BOE338 - May 8, 18:50 UTCMay 8, 19:50 UTC1h 0m
2026-05-08 BOE338 - May 8, 17:55 UTCMay 8, 18:15 UTC20m
2026-05-06 BOE338 - May 6, 21:55 UTCMay 6, 22:50 UTC55m
2026-05-06 BOE338 - May 6, 20:20 UTCMay 6, 21:20 UTC1h 0m
2026-04-21 BOE338 RNT → BFI Apr 21, 18:00 UTCApr 21, 20:30 UTC2h 30m
2026-04-16 BOE123 RNT → RNT Apr 16, 03:09 UTCApr 16, 03:19 UTC10m
2026-04-16 BOE123 RNT → RNT Apr 16, 02:45 UTCApr 16, 03:04 UTC20m

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 N9002W page for operator, model, and routing details .

Mode-S AC71DF frequently asked

What is Mode-S code AC71DF?
AC71DF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N9002W.
Where is Mode-S AC71DF registered?
Mode-S code AC71DF 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 AC71DF broadcasting right now?
No active broadcast right now. Last signal was 13d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC71DF, octal 53070737, decimal 11,301,343.
What flights does AC71DF operate?
Mode-S AC71DF has broadcast 2 distinct callsigns, including BOE338, BOE123.