Apparatus

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sensors Mode-S transponder

AA21BA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N752CS · BOEING 757-200

Hex
AA21BA
Octal
52420672
Decimal
11,149,754
Country
US
Tail
N752CS
Type
B752
No current signal · last broadcast 1d ago
Flights observed
57
Distinct callsigns
13
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AA21BA.

Country allocation

The ICAO 24-bit address AA21BA 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 13 distinct

Callsign Airline Flights Last seen
CSB805 21 Air 10 2026-05-29
CSB405 21 Air 10 2026-05-30
CSB585 21 Air 7 2026-05-19
CSB185 21 Air 7 2026-05-20
CSB594 21 Air 6 2026-05-25
CSB9149 21 Air 4 2026-04-22
CSB599 21 Air 3 2026-05-22
CSB199 21 Air 3 2026-05-22
CSB194 21 Air 3 2026-05-25
CSB507 21 Air 1 2026-06-01
CSB2021 21 Air 1 2026-04-27
CSB2001 21 Air 1 2026-04-27
CSB107 21 Air 1 2026-06-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-06-02 CSB107 HRL → CVG Jun 2, 02:05 UTCJun 2, 04:45 UTC2h 40m
2026-06-01 CSB507 CVG → HRL Jun 1, 04:15 UTCJun 1, 06:45 UTC2h 30m
2026-05-30 CSB405 SFO → CVG May 30, 03:10 UTCMay 30, 07:10 UTC4h 0m
2026-05-29 CSB805 CVG → SFO May 29, 11:00 UTCMay 29, 15:10 UTC4h 10m
2026-05-29 CSB405 SFO → CVG May 29, 03:00 UTCMay 29, 07:05 UTC4h 5m
2026-05-28 CSB805 CVG → SFO May 28, 11:35 UTCMay 28, 16:00 UTC4h 25m
2026-05-28 CSB405 SFO → CVG May 28, 03:05 UTCMay 28, 07:05 UTC4h 0m
2026-05-27 CSB805 CVG → SFO May 27, 10:55 UTCMay 27, 15:05 UTC4h 10m
2026-05-27 CSB405 SFO → CVG May 27, 02:59 UTCMay 27, 07:05 UTC4h 6m
2026-05-26 CSB805 CVG → SFO May 26, 10:50 UTCMay 26, 15:09 UTC4h 20m
2026-05-25 CSB194 DEN → CVG May 25, 13:40 UTCMay 25, 16:40 UTC3h 0m
2026-05-25 CSB594 CVG → DEN May 25, 10:40 UTCMay 25, 11:40 UTC1h 0m
2026-05-25 CSB594 CVG → DEN May 25, 06:45 UTCMay 25, 09:15 UTC2h 30m
2026-05-22 CSB199 MIA → CVG May 22, 15:40 UTCMay 22, 17:40 UTC2h 0m
2026-05-22 CSB599 CVG → MIA May 22, 08:20 UTCMay 22, 10:30 UTC2h 10m
2026-05-21 CSB199 MIA → CVG May 21, 15:40 UTCMay 21, 17:45 UTC2h 5m
2026-05-21 CSB599 CVG → MIA May 21, 08:05 UTCMay 21, 10:10 UTC2h 5m
2026-05-20 CSB199 MIA → CVG May 20, 15:20 UTCMay 20, 17:40 UTC2h 20m
2026-05-20 CSB599 CVG → MIA May 20, 08:00 UTCMay 20, 10:00 UTC2h 0m
2026-05-20 CSB185 MSP → CVG May 20, 02:55 UTCMay 20, 04:20 UTC1h 25m
2026-05-19 CSB585 CVG → MSP May 19, 10:25 UTCMay 19, 11:55 UTC1h 30m
2026-05-16 CSB405 SFO → CVG May 16, 03:00 UTCMay 16, 06:55 UTC3h 56m
2026-05-15 CSB805 CVG → SFO May 15, 10:55 UTCMay 15, 15:25 UTC4h 29m
2026-05-14 CSB405 SFO → CVG May 14, 03:00 UTCMay 14, 06:55 UTC3h 55m
2026-05-13 CSB805 CVG → SFO May 13, 10:45 UTCMay 13, 15:10 UTC4h 25m
2026-05-13 CSB405 SFO → CVG May 13, 03:00 UTCMay 13, 06:55 UTC3h 55m
2026-05-12 CSB805 CVG → SFO May 12, 10:45 UTCMay 12, 15:10 UTC4h 25m
2026-05-12 CSB194 DEN → CVG May 12, 04:20 UTCMay 12, 06:25 UTC2h 5m
2026-05-11 CSB594 CVG → DEN May 11, 10:25 UTCMay 11, 11:30 UTC1h 5m
2026-05-11 CSB594 CVG → DEN May 11, 06:40 UTCMay 11, 09:05 UTC2h 25m
2026-05-09 CSB405 SFO → CVG May 9, 03:10 UTCMay 9, 06:55 UTC3h 45m
2026-05-08 CSB805 CVG → SFO May 8, 10:59 UTCMay 8, 15:40 UTC4h 40m
2026-05-08 CSB405 SFO → CVG May 8, 03:49 UTCMay 8, 07:39 UTC3h 50m
2026-05-07 CSB805 CVG → SFO May 7, 10:55 UTCMay 7, 15:25 UTC4h 30m
2026-05-06 CSB405 SFO → CVG May 6, 02:55 UTCMay 6, 06:50 UTC3h 55m
2026-05-05 CSB805 CVG → SFO May 5, 10:50 UTCMay 5, 16:15 UTC5h 25m
2026-05-05 CSB194 DEN → CVG May 5, 02:10 UTCMay 5, 04:55 UTC2h 45m
2026-05-04 CSB594 CVG → DEN May 4, 10:35 UTCMay 4, 11:40 UTC1h 5m
2026-05-04 CSB594 CVG → DEN May 4, 06:05 UTCMay 4, 08:45 UTC2h 40m
2026-05-02 CSB185 MSP → CVG May 2, 03:05 UTCMay 2, 04:35 UTC1h 30m
2026-05-01 CSB585 CVG → MSP May 1, 10:35 UTCMay 1, 12:00 UTC1h 25m
2026-05-01 CSB185 MSP → CVG May 1, 02:35 UTCMay 1, 03:55 UTC1h 20m
2026-04-30 CSB585 CVG → MSP Apr 30, 10:25 UTCApr 30, 11:55 UTC1h 30m
2026-04-30 CSB185 MSP → CVG Apr 30, 02:50 UTCApr 30, 04:10 UTC1h 20m
2026-04-29 CSB585 CVG → MSP Apr 29, 10:30 UTCApr 29, 12:00 UTC1h 30m
2026-04-29 CSB185 MSP → CVG Apr 29, 02:40 UTCApr 29, 04:05 UTC1h 25m
2026-04-28 CSB585 CVG → MSP Apr 28, 12:40 UTCApr 28, 14:10 UTC1h 30m
2026-04-27 CSB2001 MIA → CVG Apr 27, 12:00 UTCApr 27, 14:35 UTC2h 35m
2026-04-27 CSB2021 DEN → CVG Apr 27, 05:40 UTCApr 27, 08:05 UTC2h 25m
2026-04-25 CSB185 MSP → CVG Apr 25, 02:55 UTCApr 25, 04:15 UTC1h 20m

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 N752CS page for operator, model, and routing details .

Mode-S AA21BA frequently asked

What is Mode-S code AA21BA?
AA21BA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N752CS.
Where is Mode-S AA21BA registered?
Mode-S code AA21BA 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 AA21BA broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA21BA, octal 52420672, decimal 11,149,754.
What flights does AA21BA operate?
Mode-S AA21BA has broadcast 13 distinct callsigns, including CSB805, CSB405, CSB585, CSB185, CSB594.