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sensors Mode-S transponder

A3959D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N33YA · operated by BLIEDEN IRA A

Hex
A3959D
Octal
50712635
Decimal
10,720,669
Country
US
Tail
N33YA
Type
A33P
No current signal · last broadcast 9d ago
Flights observed
87
Distinct callsigns
1
Country
US
Last broadcast
9d ago

Last known position

Most recent position reported by Mode-S A3959D.

Country allocation

The ICAO 24-bit address A3959D 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
N33YA - 86 2026-07-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-24 N33YA - Jul 24, 21:20 UTCJul 24, 21:30 UTC10m
2026-07-24 N33YA - Jul 24, 21:00 UTCJul 24, 21:05 UTC5m
2026-07-24 N33YA - Jul 24, 20:30 UTCJul 24, 20:45 UTC15m
2026-07-24 N33YA - Jul 24, 19:40 UTCJul 24, 19:55 UTC15m
2026-07-24 N33YA - Jul 24, 19:20 UTCJul 24, 19:25 UTC5m
2026-07-24 N33YA - Jul 24, 18:35 UTCJul 24, 19:15 UTC40m
2026-07-24 N33YA - Jul 24, 18:05 UTCJul 24, 18:20 UTC15m
2026-07-24 N33YA - Jul 24, 17:20 UTCJul 24, 17:40 UTC20m
2026-07-20 N33YA - Jul 20, 19:55 UTCJul 20, 20:00 UTC5m
2026-07-20 N33YA - Jul 20, 19:40 UTCJul 20, 19:50 UTC10m
2026-07-20 N33YA - Jul 20, 19:05 UTCJul 20, 19:25 UTC20m
2026-07-20 N33YA - Jul 20, 16:50 UTCJul 20, 17:10 UTC20m
2026-07-20 N33YA - Jul 20, 16:30 UTCJul 20, 16:40 UTC10m
2026-07-11 N33YA - Jul 11, 19:50 UTCJul 11, 20:20 UTC30m
2026-07-11 N33YA - Jul 11, 19:35 UTCJul 11, 19:45 UTC10m
2026-07-11 N33YA - Jul 11, 19:20 UTCJul 11, 19:30 UTC10m
2026-07-11 N33YA - Jul 11, 19:05 UTCJul 11, 19:15 UTC10m
2026-07-11 N33YA - Jul 11, 18:40 UTCJul 11, 18:55 UTC15m
2026-07-11 N33YA - Jul 11, 18:25 UTCJul 11, 18:35 UTC10m
2026-07-11 N33YA - Jul 11, 18:10 UTCJul 11, 18:20 UTC10m
2026-07-11 N33YA - Jul 11, 17:55 UTCJul 11, 18:00 UTC5m
2026-07-11 N33YA - Jul 11, 17:25 UTCJul 11, 17:40 UTC15m
2026-07-11 N33YA - Jul 11, 17:10 UTCJul 11, 17:15 UTC5m
2026-07-11 N33YA - Jul 11, 16:55 UTCJul 11, 17:00 UTC5m
2026-07-11 N33YA - Jul 11, 16:40 UTCJul 11, 16:50 UTC10m
2026-07-05 N33YA - Jul 5, 20:40 UTCJul 5, 21:05 UTC25m
2026-07-05 N33YA - Jul 5, 20:25 UTCJul 5, 20:30 UTC5m
2026-07-05 N33YA - Jul 5, 19:20 UTCJul 5, 20:00 UTC40m
2026-07-05 N33YA - Jul 5, 18:20 UTCJul 5, 18:30 UTC10m
2026-07-05 N33YA - Jul 5, 18:05 UTCJul 5, 18:15 UTC10m
2026-07-05 N33YA - Jul 5, 17:40 UTCJul 5, 17:45 UTC5m
2026-06-29 N33YA - Jun 29, 20:54 UTCJun 29, 21:19 UTC25m
2026-06-29 N33YA - Jun 29, 20:40 UTCJun 29, 20:44 UTC5m
2026-06-29 N33YA - Jun 29, 20:19 UTCJun 29, 20:35 UTC15m
2026-06-29 N33YA - Jun 29, 19:44 UTCJun 29, 20:04 UTC20m
2026-06-29 N33YA - Jun 29, 19:29 UTCJun 29, 19:39 UTC10m
2026-06-29 N33YA - Jun 29, 18:39 UTCJun 29, 19:09 UTC30m
2026-06-29 N33YA - Jun 29, 18:25 UTCJun 29, 18:34 UTC10m
2026-06-29 N33YA - Jun 29, 17:55 UTCJun 29, 18:14 UTC20m
2026-06-29 N33YA - Jun 29, 17:19 UTCJun 29, 17:30 UTC10m
2026-06-29 N33YA - Jun 29, 17:05 UTCJun 29, 17:14 UTC10m
2026-06-29 N33YA - Jun 29, 16:50 UTCJun 29, 16:59 UTC10m
2026-06-16 N33YA - Jun 16, 21:10 UTCJun 16, 21:30 UTC20m
2026-06-16 N33YA - Jun 16, 20:50 UTCJun 16, 21:05 UTC15m
2026-06-16 N33YA - Jun 16, 20:00 UTCJun 16, 20:45 UTC45m
2026-06-16 N33YA - Jun 16, 19:35 UTCJun 16, 19:55 UTC21m
2026-06-16 N33YA - Jun 16, 18:20 UTCJun 16, 18:55 UTC35m
2026-06-16 N33YA - Jun 16, 16:25 UTCJun 16, 18:15 UTC1h 50m
2026-06-03 N33YA - Jun 3, 20:20 UTCJun 3, 21:00 UTC40m
2026-06-03 - - Jun 3, 19:25 UTCJun 3, 19:35 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 N33YA page for operator, model, and routing details .

Mode-S A3959D frequently asked

What is Mode-S code A3959D?
A3959D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N33YA.
Where is Mode-S A3959D registered?
Mode-S code A3959D 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 A3959D broadcasting right now?
No active broadcast right now. Last signal was 9d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A3959D, octal 50712635, decimal 10,720,669.
What flights does A3959D operate?
Mode-S A3959D has broadcast 1 distinct callsign, including N33YA.