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sensors Mode-S transponder

A18CF7

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N1997R · operated by UND AEROSPACE FOUNDATION

Hex
A18CF7
Octal
50306367
Decimal
10,587,383
Country
US
Tail
N1997R
No current signal · last broadcast Jul 18, 20:00 UTC
Flights observed
70
Distinct callsigns
2
Country
US
Last broadcast
Jul 18, 20:00 UTC

Last known position

Most recent position reported by Mode-S A18CF7.

Country allocation

The ICAO 24-bit address A18CF7 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 2 distinct

Callsign Airline Flights Last seen
N1997R - 49 2026-06-26
NDU9D - 21 2026-07-18

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-18 NDU9D - Jul 18, 19:10 UTCJul 18, 20:00 UTC50m
2026-07-18 NDU9D - Jul 18, 17:35 UTCJul 18, 17:50 UTC15m
2026-07-18 NDU9D - Jul 18, 16:20 UTCJul 18, 17:00 UTC40m
2026-07-18 NDU9D - Jul 18, 12:55 UTCJul 18, 13:25 UTC30m
2026-07-15 NDU9D - Jul 15, 16:00 UTCJul 15, 16:15 UTC15m
2026-07-15 NDU9D - Jul 15, 14:00 UTCJul 15, 14:35 UTC35m
2026-07-15 NDU9D - Jul 15, 12:25 UTCJul 15, 13:20 UTC55m
2026-07-14 NDU9D - Jul 14, 13:45 UTCJul 14, 14:10 UTC25m
2026-07-09 NDU9D - Jul 9, 22:40 UTCJul 9, 23:05 UTC25m
2026-07-09 NDU9D - Jul 9, 21:00 UTCJul 9, 21:25 UTC25m
2026-07-09 NDU9D - Jul 9, 17:10 UTCJul 9, 17:40 UTC30m
2026-07-09 NDU9D - Jul 9, 00:25 UTCJul 9, 00:55 UTC30m
2026-07-08 NDU9D - Jul 8, 23:10 UTCJul 8, 23:35 UTC25m
2026-07-08 NDU9D - Jul 8, 18:45 UTCJul 8, 19:20 UTC35m
2026-07-08 NDU9D - Jul 8, 16:05 UTCJul 8, 16:40 UTC35m
2026-07-01 NDU9D - Jul 1, 20:25 UTCJul 1, 20:35 UTC10m
2026-07-01 NDU9D - Jul 1, 16:45 UTCJul 1, 17:05 UTC20m
2026-07-01 NDU9D - Jul 1, 15:15 UTCJul 1, 15:45 UTC30m
2026-07-01 NDU9D - Jul 1, 13:45 UTCJul 1, 14:25 UTC40m
2026-06-30 NDU9D - Jun 30, 14:00 UTCJun 30, 14:35 UTC35m
2026-06-30 NDU9D - Jun 30, 12:10 UTCJun 30, 12:40 UTC30m
2026-06-26 N1997R - Jun 26, 21:24 UTCJun 26, 21:55 UTC30m
2026-06-26 N1997R - Jun 26, 20:04 UTCJun 26, 20:34 UTC30m
2026-06-26 N1997R - Jun 26, 18:09 UTCJun 26, 18:29 UTC20m
2026-06-26 N1997R - Jun 26, 15:39 UTCJun 26, 16:09 UTC30m
2026-06-26 N1997R - Jun 26, 14:09 UTCJun 26, 14:39 UTC30m
2026-06-26 N1997R - Jun 26, 12:14 UTCJun 26, 12:55 UTC40m
2026-06-25 N1997R - Jun 25, 19:54 UTCJun 25, 20:19 UTC25m
2026-06-25 N1997R - Jun 25, 18:50 UTCJun 25, 19:15 UTC25m
2026-06-25 N1997R - Jun 25, 17:14 UTCJun 25, 17:39 UTC25m
2026-06-25 N1997R - Jun 25, 15:34 UTCJun 25, 16:05 UTC30m
2026-06-25 N1997R - Jun 25, 13:55 UTCJun 25, 14:09 UTC15m
2026-06-25 N1997R - Jun 25, 12:04 UTCJun 25, 12:54 UTC50m
2026-06-22 N1997R - Jun 22, 18:30 UTCJun 22, 19:00 UTC30m
2026-06-22 N1997R - Jun 22, 12:05 UTCJun 22, 12:30 UTC25m
2026-06-19 N1997R - Jun 19, 12:29 UTCJun 19, 12:39 UTC10m
2026-06-18 N1997R - Jun 18, 20:55 UTCJun 18, 21:05 UTC10m
2026-06-18 N1997R - Jun 18, 15:20 UTCJun 18, 15:45 UTC25m
2026-06-18 N1997R - Jun 18, 13:55 UTCJun 18, 14:20 UTC25m
2026-06-17 N1997R - Jun 17, 14:00 UTCJun 17, 14:20 UTC20m
2026-06-16 N1997R - Jun 16, 20:20 UTCJun 16, 20:45 UTC25m
2026-06-16 N1997R - Jun 16, 18:39 UTCJun 16, 19:00 UTC20m
2026-06-16 N1997R - Jun 16, 17:15 UTCJun 16, 17:35 UTC20m
2026-06-16 N1997R - Jun 16, 12:39 UTCJun 16, 13:25 UTC45m
2026-06-15 N1997R - Jun 15, 19:05 UTCJun 15, 19:14 UTC10m
2026-06-15 N1997R - Jun 15, 17:10 UTCJun 15, 17:30 UTC20m
2026-06-15 N1997R - Jun 15, 12:35 UTCJun 15, 13:10 UTC35m
2026-06-12 N1997R - Jun 12, 15:25 UTCJun 12, 16:00 UTC35m
2026-06-10 N1997R - Jun 10, 21:15 UTCJun 10, 21:25 UTC10m
2026-06-10 N1997R - Jun 10, 19:30 UTCJun 10, 19:45 UTC15m

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 N1997R page for operator, model, and routing details .

Mode-S A18CF7 frequently asked

What is Mode-S code A18CF7?
A18CF7 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N1997R.
Where is Mode-S A18CF7 registered?
Mode-S code A18CF7 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 A18CF7 broadcasting right now?
No active broadcast right now. Last signal was Jul 18, 20:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A18CF7, octal 50306367, decimal 10,587,383.
What flights does A18CF7 operate?
Mode-S A18CF7 has broadcast 2 distinct callsigns, including N1997R, NDU9D.