Apparatus

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sensors Mode-S transponder

AD661B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N9621M · MOONEY M-20 · operated by SKYS MOONEY LLC

Hex
AD661B
Octal
53263033
Decimal
11,363,867
Country
US
Tail
N9621M
Type
M20P
No current signal · last broadcast 1d ago
Flights observed
78
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AD661B.

Country allocation

The ICAO 24-bit address AD661B 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
N9621M - 78 2026-07-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-19 N9621M - Jul 19, 20:45 UTCJul 19, 21:45 UTC1h 0m
2026-07-19 N9621M - Jul 19, 19:05 UTCJul 19, 20:05 UTC1h 0m
2026-07-17 N9621M - Jul 17, 18:29 UTCJul 17, 19:05 UTC35m
2026-07-17 N9621M - Jul 17, 15:35 UTCJul 17, 17:15 UTC1h 40m
2026-07-14 N9621M BDL → MMN Jul 14, 18:40 UTCJul 14, 19:10 UTC30m
2026-07-14 N9621M - Jul 14, 15:55 UTCJul 14, 16:25 UTC30m
2026-07-11 N9621M - Jul 11, 00:20 UTCJul 11, 01:05 UTC45m
2026-07-10 N9621M - Jul 10, 23:20 UTCJul 10, 23:35 UTC15m
2026-07-09 N9621M - Jul 9, 21:50 UTCJul 9, 22:55 UTC1h 5m
2026-07-09 N9621M - Jul 9, 18:40 UTCJul 9, 19:25 UTC45m
2026-07-09 N9621M - Jul 9, 17:45 UTCJul 9, 18:05 UTC20m
2026-07-08 N9621M - Jul 8, 22:50 UTCJul 8, 23:00 UTC10m
2026-07-08 N9621M - Jul 8, 16:05 UTCJul 8, 16:45 UTC40m
2026-07-01 N9621M - Jul 1, 17:55 UTCJul 1, 18:55 UTC1h 0m
2026-07-01 N9621M - Jul 1, 13:50 UTCJul 1, 14:10 UTC20m
2026-06-30 N9621M - Jun 30, 19:00 UTCJun 30, 19:15 UTC15m
2026-06-30 N9621M OWD → OWD Jun 30, 14:40 UTCJun 30, 16:15 UTC1h 35m
2026-06-30 N9621M - Jun 30, 01:14 UTCJun 30, 01:25 UTC10m
2026-06-29 N9621M - Jun 29, 21:19 UTCJun 29, 22:30 UTC1h 10m
2026-06-25 N9621M - Jun 25, 23:19 UTCJun 26, 00:24 UTC1h 5m
2026-06-25 N9621M - Jun 25, 14:59 UTCJun 25, 17:20 UTC2h 20m
2026-06-25 N9621M - Jun 25, 12:50 UTCJun 25, 14:20 UTC1h 30m
2026-06-21 N9621M PVC → MMN Jun 21, 19:20 UTCJun 21, 20:05 UTC45m
2026-06-21 N9621M - Jun 21, 14:34 UTCJun 21, 15:09 UTC35m
2026-06-20 N9621M - Jun 20, 14:24 UTCJun 20, 14:35 UTC10m
2026-06-20 N9621M - Jun 20, 12:24 UTCJun 20, 14:14 UTC1h 50m
2026-06-15 N9621M - Jun 15, 14:10 UTCJun 15, 15:45 UTC1h 35m
2026-06-15 N9621M - Jun 15, 13:40 UTCJun 15, 14:05 UTC25m
2026-06-14 N9621M - Jun 14, 18:55 UTCJun 14, 19:30 UTC35m
2026-06-14 N9621M - Jun 14, 15:30 UTCJun 14, 16:00 UTC30m
2026-06-14 N9621M - Jun 14, 00:20 UTCJun 14, 01:05 UTC45m
2026-06-13 N9621M - Jun 13, 22:30 UTCJun 13, 23:10 UTC40m
2026-06-13 N9621M - Jun 13, 11:50 UTCJun 13, 12:40 UTC50m
2026-06-10 N9621M - Jun 10, 16:20 UTCJun 10, 18:00 UTC1h 40m
2026-06-10 N9621M - Jun 10, 15:05 UTCJun 10, 15:15 UTC10m
2026-06-10 N9621M - Jun 10, 13:35 UTCJun 10, 14:05 UTC30m
2026-06-08 N9621M - Jun 8, 13:45 UTCJun 8, 14:55 UTC1h 10m
2026-06-07 N9621M GON → MMN Jun 7, 19:30 UTCJun 7, 20:15 UTC45m
2026-06-07 N9621M - Jun 7, 16:05 UTCJun 7, 16:35 UTC30m
2026-06-06 N9621M - Jun 6, 21:40 UTCJun 6, 22:25 UTC45m
2026-06-06 N9621M - Jun 6, 18:35 UTCJun 6, 18:55 UTC20m
2026-06-05 N9621M - Jun 5, 19:30 UTCJun 5, 19:40 UTC10m
2026-06-05 N9621M FRG → MMN Jun 5, 16:10 UTCJun 5, 17:15 UTC1h 5m
2026-06-05 N9621M OWD → FRG Jun 5, 14:25 UTCJun 5, 15:30 UTC1h 5m
2026-06-05 N9621M - Jun 5, 12:10 UTCJun 5, 12:20 UTC10m
2026-06-05 N9621M - Jun 5, 00:25 UTCJun 5, 00:50 UTC25m
2026-06-04 N9621M - Jun 4, 22:20 UTCJun 4, 22:55 UTC35m
2026-05-26 N9621M - May 26, 16:55 UTCMay 26, 17:35 UTC40m
2026-05-26 N9621M - May 26, 15:20 UTCMay 26, 16:10 UTC50m
2026-05-22 N9621M OWD → MMN May 22, 11:15 UTCMay 22, 11:35 UTC20m

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 N9621M page for operator, model, and routing details .

Mode-S AD661B frequently asked

What is Mode-S code AD661B?
AD661B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N9621M.
Where is Mode-S AD661B registered?
Mode-S code AD661B 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 AD661B 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 AD661B, octal 53263033, decimal 11,363,867.
What flights does AD661B operate?
Mode-S AD661B has broadcast 1 distinct callsign, including N9621M.