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sensors Mode-S transponder

AA9521

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N781KC · operated by PIPER AIRCRAFT INC

Hex
AA9521
Octal
52512441
Decimal
11,179,297
Country
US
Tail
N781KC
No current signal · last broadcast 2d ago
Flights observed
59
Distinct callsigns
1
Country
US
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S AA9521.

Country allocation

The ICAO 24-bit address AA9521 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
N781KC - 59 2026-07-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-20 N781KC - Jul 20, 17:40 UTCJul 20, 18:35 UTC55m
2026-07-19 N781KC HSH → DVT Jul 19, 16:10 UTCJul 19, 17:15 UTC1h 5m
2026-07-18 N781KC - Jul 18, 21:00 UTCJul 18, 22:00 UTC1h 0m
2026-07-17 N781KC HSH → DVT Jul 17, 22:00 UTCJul 17, 23:10 UTC1h 10m
2026-07-15 N781KC - Jul 15, 21:35 UTCJul 15, 22:20 UTC45m
2026-07-15 N781KC - Jul 15, 20:50 UTCJul 15, 21:05 UTC15m
2026-07-15 N781KC - Jul 15, 15:50 UTCJul 15, 16:05 UTC15m
2026-07-15 N781KC - Jul 15, 14:45 UTCJul 15, 15:15 UTC30m
2026-07-13 N781KC - Jul 13, 13:40 UTCJul 13, 14:35 UTC55m
2026-07-10 N781KC HSH → DVT Jul 10, 22:55 UTCJul 10, 23:55 UTC1h 0m
2026-07-07 N781KC - Jul 7, 12:30 UTCJul 7, 13:30 UTC1h 0m
2026-07-02 N781KC HSH → DVT Jul 2, 16:25 UTCJul 2, 17:25 UTC1h 0m
2026-06-29 N781KC - Jun 29, 13:24 UTCJun 29, 14:25 UTC1h 0m
2026-06-26 N781KC HSH → DVT Jun 26, 21:59 UTCJun 26, 23:04 UTC1h 5m
2026-06-22 N781KC - Jun 22, 14:05 UTCJun 22, 15:05 UTC1h 0m
2026-06-18 N781KC - Jun 18, 19:45 UTCJun 18, 20:05 UTC20m
2026-06-18 N781KC - Jun 18, 17:00 UTCJun 18, 17:30 UTC30m
2026-06-18 N781KC - Jun 18, 00:00 UTCJun 18, 00:25 UTC25m
2026-06-17 N781KC - Jun 17, 20:50 UTCJun 17, 21:20 UTC30m
2026-06-15 N781KC - Jun 15, 21:30 UTCJun 15, 22:25 UTC55m
2026-06-15 N781KC - Jun 15, 20:30 UTCJun 15, 20:54 UTC25m
2026-06-15 N781KC - Jun 15, 17:25 UTCJun 15, 19:10 UTC1h 45m
2026-06-07 N781KC SDX → DVT Jun 7, 21:25 UTCJun 7, 21:50 UTC25m
2026-06-07 N781KC - Jun 7, 18:50 UTCJun 7, 19:00 UTC10m
2026-06-07 N781KC - Jun 7, 17:00 UTCJun 7, 18:00 UTC1h 0m
2026-06-06 N781KC - Jun 6, 22:50 UTCJun 6, 23:19 UTC30m
2026-06-06 N781KC - Jun 6, 21:35 UTCJun 6, 22:00 UTC25m
2026-06-06 N781KC DVT → HII Jun 6, 18:55 UTCJun 6, 20:19 UTC1h 25m
2026-06-05 N781KC APA → DVT Jun 5, 21:15 UTCJun 5, 23:20 UTC2h 5m
2026-06-05 N781KC - Jun 5, 17:20 UTCJun 5, 19:20 UTC2h 0m
2026-05-21 N781KC - May 21, 17:35 UTCMay 21, 18:15 UTC40m
2026-05-21 N781KC - May 21, 15:55 UTCMay 21, 16:20 UTC25m
2026-05-18 N781KC - May 18, 20:00 UTCMay 18, 22:10 UTC2h 10m
2026-05-18 N781KC - May 18, 17:25 UTCMay 18, 19:25 UTC1h 59m
2026-05-15 N781KC LNK → OJC May 15, 23:10 UTCMay 15, 23:50 UTC40m
2026-05-14 N781KC OJC → LNK May 14, 20:00 UTCMay 14, 20:50 UTC50m
2026-05-11 N781KC - May 11, 19:25 UTCMay 11, 19:40 UTC15m
2026-05-11 N781KC - May 11, 17:45 UTCMay 11, 18:20 UTC35m
2026-05-10 N781KC LNK → OJC May 10, 23:55 UTCMay 11, 00:34 UTC40m
2026-05-10 N781KC OJC → LNK May 10, 18:29 UTCMay 10, 19:15 UTC45m
2026-05-10 N781KC - May 10, 02:55 UTCMay 10, 03:40 UTC45m
2026-05-10 N781KC LNK → LNK May 10, 02:30 UTCMay 10, 02:39 UTC10m
2026-05-10 N781KC LNK → LNK May 10, 02:20 UTCMay 10, 02:24 UTC5m
2026-05-09 N781KC - May 9, 19:14 UTCMay 9, 20:05 UTC50m
2026-05-06 N781KC - May 6, 20:45 UTCMay 6, 21:30 UTC45m
2026-05-06 N781KC - May 6, 19:50 UTCMay 6, 20:15 UTC25m
2026-05-06 N781KC - May 6, 17:20 UTCMay 6, 18:20 UTC59m
2026-05-06 N781KC - May 6, 15:05 UTCMay 6, 16:20 UTC1h 15m
2026-05-06 N781KC - May 6, 13:10 UTCMay 6, 13:55 UTC45m
2026-05-03 N781KC - May 3, 19:55 UTCMay 3, 20:35 UTC40m

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 N781KC page for operator, model, and routing details .

Mode-S AA9521 frequently asked

What is Mode-S code AA9521?
AA9521 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N781KC.
Where is Mode-S AA9521 registered?
Mode-S code AA9521 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 AA9521 broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA9521, octal 52512441, decimal 11,179,297.
What flights does AA9521 operate?
Mode-S AA9521 has broadcast 1 distinct callsign, including N781KC.