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sensors Mode-S transponder

ABAB21

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N851AT · PIPER PA-44 Seminole · operated by ATP TAA LLC

Hex
ABAB21
Octal
52725441
Decimal
11,250,465
Country
US
Tail
N851AT
Type
PA44
No current signal · last broadcast 5h ago
Flights observed
136
Distinct callsigns
1
Country
US
Last broadcast
5h ago

Last known position

Most recent position reported by Mode-S ABAB21.

Country allocation

The ICAO 24-bit address ABAB21 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
CXK1102 - 136 2026-07-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-18 CXK1102 - Jul 18, 17:35 UTCJul 18, 18:50 UTC1h 15m
2026-07-18 CXK1102 - Jul 18, 00:35 UTCJul 18, 01:45 UTC1h 10m
2026-07-17 CXK1102 - Jul 17, 03:50 UTCJul 17, 04:59 UTC1h 10m
2026-07-14 CXK1102 - Jul 14, 01:00 UTCJul 14, 02:45 UTC1h 45m
2026-07-13 CXK1102 - Jul 13, 22:00 UTCJul 13, 23:20 UTC1h 20m
2026-07-12 CXK1102 - Jul 12, 17:45 UTCJul 12, 18:01 UTC15m
2026-07-12 CXK1102 - Jul 12, 16:25 UTCJul 12, 16:40 UTC15m
2026-07-11 CXK1102 - Jul 11, 18:50 UTCJul 11, 20:05 UTC1h 15m
2026-07-11 CXK1102 - Jul 11, 15:45 UTCJul 11, 17:00 UTC1h 15m
2026-07-11 CXK1102 - Jul 11, 00:20 UTCJul 11, 00:35 UTC15m
2026-07-10 CXK1102 - Jul 10, 22:50 UTCJul 10, 23:25 UTC35m
2026-07-10 CXK1102 - Jul 10, 15:25 UTCJul 10, 15:55 UTC30m
2026-07-09 CXK1102 - Jul 9, 20:35 UTCJul 9, 21:00 UTC25m
2026-07-09 CXK1102 - Jul 9, 14:10 UTCJul 9, 15:35 UTC1h 25m
2026-07-08 CXK1102 - Jul 8, 21:45 UTCJul 9, 00:50 UTC3h 5m
2026-07-07 CXK1102 - Jul 7, 22:25 UTCJul 7, 23:20 UTC55m
2026-07-07 CXK1102 - Jul 7, 16:05 UTCJul 7, 16:55 UTC50m
2026-07-07 CXK1102 - Jul 7, 14:00 UTCJul 7, 15:15 UTC1h 15m
2026-07-06 CXK1102 - Jul 6, 21:15 UTCJul 6, 22:25 UTC1h 10m
2026-07-06 CXK1102 - Jul 6, 18:45 UTCJul 6, 19:40 UTC55m
2026-07-05 CXK1102 - Jul 5, 16:25 UTCJul 5, 17:50 UTC1h 25m
2026-07-03 CXK1102 - Jul 3, 22:05 UTCJul 3, 23:55 UTC1h 50m
2026-07-03 CXK1102 - Jul 3, 17:20 UTCJul 3, 18:35 UTC1h 15m
2026-07-02 CXK1102 - Jul 2, 23:55 UTCJul 3, 00:05 UTC10m
2026-07-02 CXK1102 - Jul 2, 22:40 UTCJul 2, 22:55 UTC15m
2026-07-02 CXK1102 - Jul 2, 18:20 UTCJul 2, 19:30 UTC1h 10m
2026-07-01 CXK1102 - Jul 1, 22:15 UTCJul 1, 23:50 UTC1h 35m
2026-07-01 CXK1102 - Jul 1, 19:30 UTCJul 1, 20:35 UTC1h 5m
2026-07-01 CXK1102 - Jul 1, 00:40 UTCJul 1, 02:35 UTC1h 55m
2026-06-30 CXK1102 - Jun 30, 21:35 UTCJun 30, 23:10 UTC1h 35m
2026-06-30 CXK1102 - Jun 30, 18:20 UTCJun 30, 19:20 UTC1h 0m
2026-06-29 CXK1102 - Jun 29, 19:15 UTCJun 29, 20:24 UTC1h 10m
2026-06-29 CXK1102 - Jun 29, 16:29 UTCJun 29, 17:59 UTC1h 30m
2026-06-29 CXK1102 - Jun 29, 15:00 UTCJun 29, 15:39 UTC40m
2026-06-29 CXK1102 - Jun 29, 13:54 UTCJun 29, 14:54 UTC1h 0m
2026-06-28 CXK1102 - Jun 28, 23:20 UTCJun 28, 23:44 UTC25m
2026-06-28 CXK1102 - Jun 28, 16:25 UTCJun 28, 17:10 UTC45m
2026-06-27 CXK1102 - Jun 27, 19:45 UTCJun 27, 21:25 UTC1h 40m
2026-06-26 CXK1102 - Jun 26, 17:50 UTCJun 26, 18:04 UTC15m
2026-06-26 CXK1102 - Jun 26, 17:00 UTCJun 26, 17:15 UTC15m
2026-06-17 CXK1102 - Jun 17, 23:40 UTCJun 18, 01:50 UTC2h 10m
2026-06-17 CXK1102 - Jun 17, 03:20 UTCJun 17, 04:05 UTC45m
2026-06-17 CXK1102 - Jun 17, 01:35 UTCJun 17, 02:15 UTC40m
2026-06-16 CXK1102 - Jun 16, 19:19 UTCJun 16, 20:50 UTC1h 31m
2026-06-16 CXK1102 - Jun 16, 13:50 UTCJun 16, 15:45 UTC1h 55m
2026-06-16 CXK1102 - Jun 16, 04:50 UTCJun 16, 05:50 UTC1h 0m
2026-06-16 CXK1102 - Jun 16, 02:15 UTCJun 16, 03:00 UTC45m
2026-06-13 CXK1102 - Jun 13, 17:30 UTCJun 13, 18:15 UTC45m
2026-06-13 CXK1102 - Jun 13, 17:10 UTCJun 13, 17:25 UTC15m
2026-06-13 CXK1102 - Jun 13, 16:25 UTCJun 13, 16:35 UTC10m

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 N851AT page for operator, model, and routing details .

Mode-S ABAB21 frequently asked

What is Mode-S code ABAB21?
ABAB21 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N851AT.
Where is Mode-S ABAB21 registered?
Mode-S code ABAB21 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 ABAB21 broadcasting right now?
No active broadcast right now. Last signal was 5h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex ABAB21, octal 52725441, decimal 11,250,465.
What flights does ABAB21 operate?
Mode-S ABAB21 has broadcast 1 distinct callsign, including CXK1102.