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
139
Distinct callsigns
19
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 19 distinct

Callsign Airline Flights Last seen
CSB594 - 20 2026-07-15
CSB585 - 20 2026-07-10
CSB185 - 20 2026-07-11
CSB194 - 17 2026-07-16
CSB805 21 Air 15 2026-07-02
CSB405 21 Air 15 2026-07-03
CSB9149 21 Air 4 2026-04-22
CSB599 21 Air 4 2026-06-06
CSB507 - 4 2026-07-03
CSB199 21 Air 4 2026-06-06
CSB1517 - 3 2026-07-05
CSB1117 - 3 2026-07-05
CSB107 21 Air 3 2026-06-11
CSB2021 - 2 2026-07-17
CSB2027 - 1 2026-06-23
CSB2026 - 1 2026-06-24
CSB2020 - 1 2026-07-16
CSB2001 21 Air 1 2026-04-27
CSB1107 - 1 2026-07-03

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-17 CSB2021 - Jul 17, 03:14 UTCJul 17, 05:20 UTC2h 5m
2026-07-16 CSB2020 CVG → AUS Jul 16, 10:15 UTCJul 16, 12:20 UTC2h 5m
2026-07-16 CSB194 DEN → CVG Jul 16, 03:55 UTCJul 16, 06:10 UTC2h 15m
2026-07-16 CSB194 - Jul 16, 01:45 UTCJul 16, 02:50 UTC1h 5m
2026-07-15 CSB594 DEN → SLC Jul 15, 14:40 UTCJul 15, 15:35 UTC55m
2026-07-15 CSB594 - Jul 15, 10:35 UTCJul 15, 12:45 UTC2h 10m
2026-07-15 CSB194 DEN → CVG Jul 15, 04:00 UTCJul 15, 06:25 UTC2h 25m
2026-07-15 CSB194 - Jul 15, 01:25 UTCJul 15, 02:25 UTC1h 0m
2026-07-14 CSB594 DEN → SLC Jul 14, 14:15 UTCJul 14, 15:20 UTC1h 5m
2026-07-14 CSB594 - Jul 14, 10:30 UTCJul 14, 12:35 UTC2h 5m
2026-07-14 CSB194 - Jul 14, 04:30 UTCJul 14, 06:45 UTC2h 15m
2026-07-14 CSB194 SLC → DEN Jul 14, 01:25 UTCJul 14, 02:25 UTC1h 0m
2026-07-13 CSB594 DEN → SLC Jul 13, 11:00 UTCJul 13, 12:00 UTC1h 0m
2026-07-13 CSB594 - Jul 13, 06:35 UTCJul 13, 08:50 UTC2h 15m
2026-07-11 CSB185 MSP → CVG Jul 11, 02:20 UTCJul 11, 03:40 UTC1h 20m
2026-07-10 CSB585 - Jul 10, 10:40 UTCJul 10, 12:15 UTC1h 35m
2026-07-10 CSB185 MSP → CVG Jul 10, 02:30 UTCJul 10, 03:45 UTC1h 15m
2026-07-09 CSB585 - Jul 9, 11:30 UTCJul 9, 12:55 UTC1h 25m
2026-07-09 CSB185 MSP → CVG Jul 9, 02:45 UTCJul 9, 04:10 UTC1h 25m
2026-07-08 CSB585 - Jul 8, 10:30 UTCJul 8, 11:55 UTC1h 25m
2026-07-08 CSB185 - Jul 8, 02:40 UTCJul 8, 04:05 UTC1h 25m
2026-07-07 CSB585 - Jul 7, 10:30 UTCJul 7, 11:55 UTC1h 25m
2026-07-07 CSB185 MSP → CVG Jul 7, 02:50 UTCJul 7, 04:05 UTC1h 15m
2026-07-06 CSB585 - Jul 6, 06:20 UTCJul 6, 07:45 UTC1h 25m
2026-07-05 CSB1117 AUS → CVG Jul 5, 12:30 UTCJul 5, 14:40 UTC2h 10m
2026-07-05 CSB1517 - Jul 5, 07:45 UTCJul 5, 09:50 UTC2h 5m
2026-07-03 CSB1107 - Jul 3, 15:30 UTCJul 3, 17:45 UTC2h 15m
2026-07-03 CSB507 - Jul 3, 11:10 UTCJul 3, 13:20 UTC2h 10m
2026-07-03 CSB405 SFO → CVG Jul 3, 02:50 UTCJul 3, 06:40 UTC3h 50m
2026-07-02 CSB805 CVG → SFO Jul 2, 11:00 UTCJul 2, 15:25 UTC4h 25m
2026-07-02 CSB405 SFO → CVG Jul 2, 02:50 UTCJul 2, 06:51 UTC4h 1m
2026-07-01 CSB805 CVG → SFO Jul 1, 11:05 UTCJul 1, 15:20 UTC4h 15m
2026-07-01 CSB405 SFO → CVG Jul 1, 02:50 UTCJul 1, 06:45 UTC3h 55m
2026-06-30 CSB805 CVG → SFO Jun 30, 10:45 UTCJun 30, 15:05 UTC4h 20m
2026-06-30 CSB194 - Jun 30, 04:50 UTCJun 30, 06:55 UTC2h 5m
2026-06-30 CSB194 - Jun 30, 01:45 UTCJun 30, 02:45 UTC1h 0m
2026-06-29 CSB594 - Jun 29, 10:44 UTCJun 29, 11:55 UTC1h 10m
2026-06-29 CSB594 - Jun 29, 06:29 UTCJun 29, 08:54 UTC2h 25m
2026-06-28 CSB1117 AUS → CVG Jun 28, 12:15 UTCJun 28, 14:25 UTC2h 10m
2026-06-28 CSB1517 - Jun 28, 07:50 UTCJun 28, 10:00 UTC2h 10m
2026-06-27 CSB185 MSP → CVG Jun 27, 02:50 UTCJun 27, 04:05 UTC1h 15m
2026-06-26 CSB585 - Jun 26, 10:25 UTCJun 26, 11:55 UTC1h 30m
2026-06-26 CSB185 MSP → CVG Jun 26, 02:30 UTCJun 26, 03:45 UTC1h 15m
2026-06-25 CSB585 - Jun 25, 10:30 UTCJun 25, 12:04 UTC1h 35m
2026-06-25 CSB185 MSP → CVG Jun 25, 02:30 UTCJun 25, 03:50 UTC1h 20m
2026-06-24 CSB585 - Jun 24, 10:30 UTCJun 24, 12:04 UTC1h 35m
2026-06-24 CSB2026 - Jun 24, 03:40 UTCJun 24, 05:49 UTC2h 10m
2026-06-23 CSB2027 CVG → AUS Jun 23, 10:10 UTCJun 23, 12:35 UTC2h 25m
2026-06-23 CSB185 - Jun 23, 02:40 UTCJun 23, 04:00 UTC1h 20m
2026-06-22 CSB585 - Jun 22, 06:25 UTCJun 22, 07:54 UTC1h 30m

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 19 distinct callsigns, including CSB594, CSB585, CSB185, CSB194, CSB805.