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sensors Mode-S transponder

A1B766

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N21CL · BELL 407 · operated by HELICOPTERS INC

Hex
A1B766
Octal
50333546
Decimal
10,598,246
Country
US
Tail
N21CL
Type
B407
No current signal · last broadcast 2h ago
Flights observed
94
Distinct callsigns
1
Country
US
Last broadcast
2h ago

Last known position

Most recent position reported by Mode-S A1B766.

Country allocation

The ICAO 24-bit address A1B766 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
N21CL - 94 2026-07-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 N21CL - Jul 14, 20:15 UTCJul 14, 20:25 UTC10m
2026-07-14 N21CL - Jul 14, 16:00 UTCJul 14, 16:30 UTC30m
2026-07-13 N21CL - Jul 13, 20:20 UTCJul 13, 20:45 UTC25m
2026-07-13 N21CL - Jul 13, 15:20 UTCJul 13, 16:30 UTC1h 10m
2026-07-10 N21CL - Jul 10, 21:50 UTCJul 10, 22:15 UTC25m
2026-07-10 N21CL - Jul 10, 18:10 UTCJul 10, 19:00 UTC50m
2026-07-09 N21CL HWO → HWO Jul 9, 21:40 UTCJul 9, 22:10 UTC30m
2026-07-09 N21CL - Jul 9, 13:25 UTCJul 9, 13:45 UTC20m
2026-07-07 N21CL - Jul 7, 18:20 UTCJul 7, 18:40 UTC20m
2026-07-07 N21CL - Jul 7, 14:15 UTCJul 7, 15:05 UTC50m
2026-07-06 N21CL - Jul 6, 16:10 UTCJul 6, 16:40 UTC30m
2026-07-01 N21CL - Jul 1, 17:55 UTCJul 1, 18:20 UTC25m
2026-07-01 N21CL HWO → HWO Jul 1, 14:15 UTCJul 1, 14:45 UTC30m
2026-06-30 N21CL - Jun 30, 15:15 UTCJun 30, 16:50 UTC1h 35m
2026-06-30 N21CL - Jun 30, 14:10 UTCJun 30, 14:35 UTC25m
2026-06-29 N21CL - Jun 29, 20:04 UTCJun 29, 20:30 UTC25m
2026-06-29 N21CL - Jun 29, 17:55 UTCJun 29, 18:25 UTC30m
2026-06-29 N21CL HWO → HWO Jun 29, 14:54 UTCJun 29, 15:14 UTC20m
2026-06-26 N21CL HWO → HWO Jun 26, 13:49 UTCJun 26, 13:59 UTC10m
2026-06-25 N21CL - Jun 25, 19:29 UTCJun 25, 20:09 UTC40m
2026-06-25 N21CL - Jun 25, 16:35 UTCJun 25, 17:25 UTC50m
2026-06-24 N21CL - Jun 24, 13:50 UTCJun 24, 14:04 UTC15m
2026-06-23 N21CL - Jun 23, 18:45 UTCJun 23, 19:10 UTC25m
2026-06-19 N21CL - Jun 19, 20:49 UTCJun 19, 21:54 UTC1h 5m
2026-06-19 N21CL HWO → HWO Jun 19, 18:39 UTCJun 19, 18:59 UTC20m
2026-06-19 N21CL - Jun 19, 13:44 UTCJun 19, 15:59 UTC2h 15m
2026-06-18 N21CL - Jun 18, 15:50 UTCJun 18, 17:10 UTC1h 20m
2026-06-17 N21CL - Jun 17, 15:46 UTCJun 17, 16:55 UTC1h 10m
2026-06-16 N21CL - Jun 16, 21:35 UTCJun 16, 22:15 UTC40m
2026-06-16 N21CL - Jun 16, 16:25 UTCJun 16, 16:50 UTC25m
2026-06-16 N21CL - Jun 16, 14:20 UTCJun 16, 14:45 UTC25m
2026-06-16 N21CL - Jun 16, 11:10 UTCJun 16, 11:25 UTC15m
2026-06-15 N21CL HWO → HWO Jun 15, 22:40 UTCJun 15, 23:09 UTC30m
2026-06-15 N21CL - Jun 15, 20:45 UTCJun 15, 20:54 UTC10m
2026-06-15 N21CL - Jun 15, 19:39 UTCJun 15, 20:04 UTC25m
2026-06-15 N21CL - Jun 15, 17:59 UTCJun 15, 18:20 UTC20m
2026-06-15 N21CL - Jun 15, 14:30 UTCJun 15, 16:19 UTC1h 50m
2026-06-12 N21CL HWO → HWO Jun 12, 16:05 UTCJun 12, 16:30 UTC25m
2026-06-11 N21CL - Jun 11, 15:30 UTCJun 11, 16:05 UTC35m
2026-06-10 N21CL - Jun 10, 20:40 UTCJun 10, 21:10 UTC30m
2026-06-10 N21CL - Jun 10, 17:05 UTCJun 10, 17:45 UTC40m
2026-06-10 N21CL - Jun 10, 14:35 UTCJun 10, 15:00 UTC25m
2026-06-09 N21CL - Jun 9, 16:45 UTCJun 9, 17:25 UTC40m
2026-06-09 N21CL - Jun 9, 15:20 UTCJun 9, 15:50 UTC30m
2026-06-08 N21CL - Jun 8, 20:15 UTCJun 8, 20:50 UTC35m
2026-06-08 N21CL - Jun 8, 18:40 UTCJun 8, 19:30 UTC50m
2026-06-05 N21CL - Jun 5, 17:55 UTCJun 5, 18:05 UTC10m
2026-05-29 N21CL - May 29, 11:10 UTCMay 29, 11:45 UTC35m
2026-05-28 N21CL - May 28, 17:35 UTCMay 28, 18:45 UTC1h 10m
2026-05-28 N21CL - May 28, 13:30 UTCMay 28, 15:00 UTC1h 30m

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 N21CL page for operator, model, and routing details .

Mode-S A1B766 frequently asked

What is Mode-S code A1B766?
A1B766 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N21CL.
Where is Mode-S A1B766 registered?
Mode-S code A1B766 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 A1B766 broadcasting right now?
No active broadcast right now. Last signal was 2h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1B766, octal 50333546, decimal 10,598,246.
What flights does A1B766 operate?
Mode-S A1B766 has broadcast 1 distinct callsign, including N21CL.