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sensors Mode-S transponder

AD57D9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N959UA · CESSNA 172 Skyhawk · operated by UNIVERSITY OF ALASKA ANCHORAGE

Hex
AD57D9
Octal
53253731
Decimal
11,360,217
Country
US
Tail
N959UA
Type
C172
No current signal · last broadcast Jul 26, 01:50 UTC
Flights observed
231
Distinct callsigns
1
Country
US
Last broadcast
Jul 26, 01:50 UTC

Last known position

Most recent position reported by Mode-S AD57D9.

Country allocation

The ICAO 24-bit address AD57D9 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
N959UA - 231 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 N959UA - Jul 26, 00:20 UTCJul 26, 01:50 UTC1h 30m
2026-07-25 N959UA MRI → MRI Jul 25, 02:10 UTCJul 25, 03:20 UTC1h 10m
2026-07-24 N959UA - Jul 24, 16:45 UTCJul 24, 17:40 UTC55m
2026-07-24 N959UA - Jul 24, 14:25 UTCJul 24, 15:35 UTC1h 10m
2026-07-22 N959UA - Jul 22, 23:25 UTCJul 22, 23:50 UTC25m
2026-07-22 N959UA - Jul 22, 17:20 UTCJul 22, 17:40 UTC20m
2026-07-22 N959UA - Jul 22, 16:45 UTCJul 22, 16:55 UTC10m
2026-07-18 N959UA - Jul 18, 04:30 UTCJul 18, 05:00 UTC30m
2026-07-17 N959UA - Jul 17, 19:09 UTCJul 17, 20:20 UTC1h 10m
2026-07-17 N959UA - Jul 17, 17:55 UTCJul 17, 18:05 UTC10m
2026-07-17 N959UA - Jul 17, 17:30 UTCJul 17, 17:40 UTC10m
2026-07-17 N959UA - Jul 17, 16:55 UTCJul 17, 17:15 UTC20m
2026-07-16 N959UA - Jul 16, 21:25 UTCJul 16, 22:30 UTC1h 5m
2026-07-16 N959UA - Jul 16, 18:59 UTCJul 16, 20:05 UTC1h 5m
2026-07-15 N959UA MRI → MRI Jul 15, 23:55 UTCJul 16, 00:55 UTC1h 0m
2026-07-11 N959UA - Jul 11, 18:50 UTCJul 11, 20:00 UTC1h 10m
2026-07-11 N959UA - Jul 11, 03:55 UTCJul 11, 05:10 UTC1h 15m
2026-07-10 N959UA - Jul 10, 17:45 UTCJul 10, 17:50 UTC5m
2026-07-10 N959UA - Jul 10, 16:55 UTCJul 10, 17:00 UTC5m
2026-07-08 N959UA - Jul 8, 19:00 UTCJul 8, 19:10 UTC10m
2026-07-08 N959UA - Jul 8, 17:50 UTCJul 8, 18:10 UTC20m
2026-07-08 N959UA - Jul 8, 17:35 UTCJul 8, 17:45 UTC10m
2026-07-08 N959UA - Jul 8, 16:55 UTCJul 8, 17:30 UTC35m
2026-07-08 N959UA - Jul 8, 02:00 UTCJul 8, 02:20 UTC20m
2026-07-07 N959UA - Jul 7, 23:55 UTCJul 8, 01:35 UTC1h 40m
2026-07-07 N959UA - Jul 7, 18:55 UTCJul 7, 19:20 UTC25m
2026-07-07 N959UA - Jul 7, 17:10 UTCJul 7, 18:10 UTC1h 0m
2026-07-06 N959UA - Jul 6, 23:30 UTCJul 7, 00:50 UTC1h 20m
2026-07-06 N959UA - Jul 6, 21:20 UTCJul 6, 22:25 UTC1h 5m
2026-07-06 N959UA - Jul 6, 19:05 UTCJul 6, 20:25 UTC1h 20m
2026-07-06 N959UA - Jul 6, 16:50 UTCJul 6, 18:00 UTC1h 10m
2026-07-03 N959UA - Jul 3, 03:35 UTCJul 3, 04:30 UTC55m
2026-07-03 N959UA - Jul 3, 02:30 UTCJul 3, 03:25 UTC55m
2026-07-02 N959UA - Jul 2, 16:55 UTCJul 2, 17:55 UTC1h 0m
2026-07-02 N959UA - Jul 2, 01:55 UTCJul 2, 03:05 UTC1h 10m
2026-07-01 N959UA - Jul 1, 23:20 UTCJul 2, 00:30 UTC1h 10m
2026-07-01 N959UA - Jul 1, 21:25 UTCJul 1, 22:25 UTC1h 0m
2026-07-01 N959UA - Jul 1, 19:15 UTCJul 1, 19:55 UTC40m
2026-07-01 N959UA - Jul 1, 16:50 UTCJul 1, 18:00 UTC1h 10m
2026-07-01 N959UA - Jul 1, 04:00 UTCJul 1, 04:55 UTC55m
2026-07-01 N959UA - Jul 1, 01:40 UTCJul 1, 02:45 UTC1h 5m
2026-06-30 N959UA - Jun 30, 19:00 UTCJun 30, 19:40 UTC40m
2026-06-29 N959UA - Jun 29, 23:49 UTCJun 30, 00:45 UTC55m
2026-06-29 N959UA MRI → MRI Jun 29, 19:39 UTCJun 29, 20:30 UTC50m
2026-06-29 N959UA - Jun 29, 16:55 UTCJun 29, 18:19 UTC1h 25m
2026-06-29 N959UA - Jun 29, 14:25 UTCJun 29, 15:45 UTC1h 20m
2026-06-27 N959UA - Jun 27, 17:20 UTCJun 27, 18:04 UTC45m
2026-06-26 N959UA - Jun 26, 23:49 UTCJun 27, 01:09 UTC1h 20m
2026-06-26 N959UA - Jun 26, 20:55 UTCJun 26, 22:05 UTC1h 10m
2026-06-26 N959UA - Jun 26, 17:04 UTCJun 26, 17:54 UTC50m

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 N959UA page for operator, model, and routing details .

Mode-S AD57D9 frequently asked

What is Mode-S code AD57D9?
AD57D9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N959UA.
Where is Mode-S AD57D9 registered?
Mode-S code AD57D9 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 AD57D9 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 01:50 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AD57D9, octal 53253731, decimal 11,360,217.
What flights does AD57D9 operate?
Mode-S AD57D9 has broadcast 1 distinct callsign, including N959UA.