Apparatus

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sensors Mode-S transponder

A21BF6

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N235KB · FLIGHT DESIGN CT · operated by SOB AERO LLC

Hex
A21BF6
Octal
50415766
Decimal
10,623,990
Country
US
Tail
N235KB
Type
FDCT
No current signal · last broadcast 9h ago
Flights observed
134
Distinct callsigns
1
Country
US
Last broadcast
9h ago

Last known position

Most recent position reported by Mode-S A21BF6.

Country allocation

The ICAO 24-bit address A21BF6 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 1 distinct

Callsign Airline Flights Last seen
N235KB - 134 2026-06-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-26 N235KB - Jun 26, 15:54 UTCJun 26, 16:44 UTC50m
2026-06-25 N235KB - Jun 25, 18:04 UTCJun 25, 18:59 UTC55m
2026-06-25 N235KB - Jun 25, 13:05 UTCJun 25, 14:24 UTC1h 20m
2026-06-24 N235KB - Jun 24, 19:55 UTCJun 24, 20:44 UTC50m
2026-06-24 N235KB OSU → OSU Jun 24, 15:59 UTCJun 24, 17:25 UTC1h 25m
2026-06-24 N235KB - Jun 24, 13:44 UTCJun 24, 15:05 UTC1h 20m
2026-06-23 N235KB - Jun 23, 17:59 UTCJun 23, 19:00 UTC1h 0m
2026-06-23 N235KB - Jun 23, 15:50 UTCJun 23, 16:29 UTC40m
2026-06-23 N235KB - Jun 23, 13:50 UTCJun 23, 14:55 UTC1h 5m
2026-06-21 N235KB - Jun 21, 17:15 UTCJun 21, 17:29 UTC15m
2026-06-21 N235KB - Jun 21, 15:49 UTCJun 21, 16:39 UTC50m
2026-06-21 N235KB - Jun 21, 13:39 UTCJun 21, 14:50 UTC1h 10m
2026-06-20 N235KB - Jun 20, 13:49 UTCJun 20, 14:54 UTC1h 5m
2026-06-19 N235KB - Jun 19, 17:44 UTCJun 19, 18:54 UTC1h 10m
2026-06-17 N235KB - Jun 17, 15:30 UTCJun 17, 16:35 UTC1h 5m
2026-06-17 N235KB - Jun 17, 13:30 UTCJun 17, 14:25 UTC55m
2026-06-15 N235KB - Jun 15, 23:50 UTCJun 16, 00:20 UTC30m
2026-06-15 N235KB - Jun 15, 22:05 UTCJun 15, 22:30 UTC25m
2026-06-15 N235KB - Jun 15, 19:55 UTCJun 15, 21:09 UTC1h 15m
2026-06-15 N235KB - Jun 15, 18:10 UTCJun 15, 19:00 UTC50m
2026-06-15 N235KB - Jun 15, 14:50 UTCJun 15, 16:09 UTC1h 20m
2026-06-15 N235KB - Jun 15, 12:49 UTCJun 15, 13:34 UTC45m
2026-06-13 N235KB - Jun 13, 19:30 UTCJun 13, 20:35 UTC1h 5m
2026-06-13 N235KB - Jun 13, 17:10 UTCJun 13, 17:35 UTC25m
2026-06-13 N235KB - Jun 13, 15:40 UTCJun 13, 16:00 UTC20m
2026-06-13 N235KB - Jun 13, 13:35 UTCJun 13, 14:35 UTC1h 0m
2026-06-12 N235KB - Jun 12, 20:40 UTCJun 12, 21:55 UTC1h 15m
2026-06-12 N235KB - Jun 12, 18:45 UTCJun 12, 19:55 UTC1h 10m
2026-06-11 N235KB - Jun 11, 11:30 UTCJun 11, 12:55 UTC1h 25m
2026-06-08 N235KB - Jun 8, 19:30 UTCJun 8, 20:20 UTC50m
2026-06-08 N235KB - Jun 8, 17:45 UTCJun 8, 18:40 UTC55m
2026-06-08 N235KB OSU → OSU Jun 8, 13:55 UTCJun 8, 14:40 UTC45m
2026-06-07 N235KB - Jun 7, 21:40 UTCJun 7, 22:55 UTC1h 15m
2026-06-07 N235KB - Jun 7, 20:15 UTCJun 7, 21:10 UTC55m
2026-06-07 N235KB - Jun 7, 18:00 UTCJun 7, 18:55 UTC55m
2026-06-07 N235KB - Jun 7, 12:05 UTCJun 7, 12:35 UTC30m
2026-06-06 N235KB - Jun 6, 14:45 UTCJun 6, 15:25 UTC40m
2026-06-04 N235KB - Jun 4, 15:45 UTCJun 4, 16:30 UTC45m
2026-06-04 N235KB - Jun 4, 13:50 UTCJun 4, 14:50 UTC1h 0m
2026-06-04 N235KB - Jun 4, 00:25 UTCJun 4, 01:05 UTC40m
2026-06-03 N235KB - Jun 3, 16:55 UTCJun 3, 17:50 UTC55m
2026-06-03 N235KB - Jun 3, 13:55 UTCJun 3, 15:20 UTC1h 25m
2026-06-01 N235KB - Jun 1, 15:35 UTCJun 1, 16:30 UTC55m
2026-05-31 N235KB - May 31, 22:20 UTCMay 31, 22:45 UTC25m
2026-05-31 N235KB - May 31, 19:45 UTCMay 31, 20:45 UTC1h 0m
2026-05-31 N235KB OSU → OSU May 31, 12:50 UTCMay 31, 14:45 UTC1h 55m
2026-05-30 N235KB - May 30, 22:35 UTCMay 30, 23:25 UTC50m
2026-05-30 N235KB - May 30, 19:50 UTCMay 30, 21:00 UTC1h 10m
2026-05-29 N235KB - May 29, 19:20 UTCMay 29, 20:20 UTC1h 0m
2026-05-29 N235KB - May 29, 14:55 UTCMay 29, 15:40 UTC45m

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 N235KB page for operator, model, and routing details .

Mode-S A21BF6 frequently asked

What is Mode-S code A21BF6?
A21BF6 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N235KB.
Where is Mode-S A21BF6 registered?
Mode-S code A21BF6 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 A21BF6 broadcasting right now?
No active broadcast right now. Last signal was 9h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A21BF6, octal 50415766, decimal 10,623,990.
What flights does A21BF6 operate?
Mode-S A21BF6 has broadcast 1 distinct callsign, including N235KB.