sensors Mode-S transponder

A1974C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N201SB · MOONEY M-20 · operated by PATTERSON JAMES L

Hex
A1974C
Octal
50313514
Decimal
10,590,028
Country
US
Tail
N201SB
Type
M20P
No current signal · last broadcast 4h ago
Flights observed
36
Distinct callsigns
1
Country
US
Last broadcast
4h ago

Last known position

Most recent position reported by Mode-S A1974C.

Country allocation

The ICAO 24-bit address A1974C 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
N201SB - 36 2026-06-08

Recent flights last 36

DateFlightRouteTakeoffLandingDuration
2026-06-08 N201SB - Jun 8, 23:55 UTCJun 9, 01:50 UTC1h 55m
2026-06-07 N201SB - Jun 7, 14:25 UTCJun 7, 17:35 UTC3h 10m
2026-06-03 N201SB - Jun 3, 17:25 UTCJun 3, 18:00 UTC35m
2026-06-03 N201SB - Jun 3, 14:35 UTCJun 3, 16:20 UTC1h 45m
2026-06-02 N201SB - Jun 2, 19:00 UTCJun 2, 20:25 UTC1h 25m
2026-06-02 N201SB - Jun 2, 15:15 UTCJun 2, 17:05 UTC1h 50m
2026-06-02 N201SB - Jun 2, 12:50 UTCJun 2, 14:00 UTC1h 10m
2026-06-01 N201SB - Jun 1, 13:15 UTCJun 1, 15:45 UTC2h 30m
2026-05-23 N201SB - May 23, 03:35 UTCMay 23, 03:50 UTC15m
2026-05-22 N201SB - May 22, 22:30 UTCMay 23, 00:25 UTC1h 55m
2026-05-22 N201SB - May 22, 19:00 UTCMay 22, 21:00 UTC2h 0m
2026-05-22 N201SB - May 22, 17:50 UTCMay 22, 18:10 UTC20m
2026-05-20 N201SB - May 20, 21:35 UTCMay 20, 23:20 UTC1h 45m
2026-05-15 N201SB - May 15, 22:55 UTCMay 16, 00:40 UTC1h 45m
2026-05-14 N201SB - May 14, 22:50 UTCMay 15, 01:50 UTC3h 0m
2026-05-12 N201SB - May 12, 12:50 UTCMay 12, 16:45 UTC3h 55m
2026-05-09 N201SB - May 9, 18:00 UTCMay 9, 18:15 UTC15m
2026-05-09 N201SB - May 9, 13:40 UTCMay 9, 14:35 UTC55m
2026-05-08 N201SB - May 8, 22:30 UTCMay 9, 00:25 UTC1h 55m
2026-05-06 N201SB - May 6, 21:35 UTCMay 6, 22:25 UTC50m
2026-05-05 N201SB - May 5, 23:35 UTCMay 6, 01:05 UTC1h 30m
2026-05-05 N201SB - May 5, 21:20 UTCMay 5, 23:00 UTC1h 40m
2026-05-03 N201SB - May 3, 16:15 UTCMay 3, 17:20 UTC1h 5m
2026-05-02 N201SB - May 2, 14:40 UTCMay 2, 17:30 UTC2h 50m
2026-04-27 N201SB - Apr 27, 20:40 UTCApr 27, 21:10 UTC30m
2026-04-26 N201SB - Apr 26, 21:45 UTCApr 27, 00:35 UTC2h 50m
2026-04-24 N201SB - Apr 24, 01:00 UTCApr 24, 01:35 UTC35m
2026-04-23 N201SB - Apr 23, 23:05 UTCApr 24, 00:10 UTC1h 5m
2026-04-23 N201SB - Apr 23, 21:50 UTCApr 23, 22:15 UTC25m
2026-04-20 N201SB - Apr 20, 22:40 UTCApr 21, 00:45 UTC2h 5m
2026-04-19 N201SB - Apr 19, 14:50 UTCApr 19, 16:55 UTC2h 5m
2026-04-18 N201SB - Apr 18, 00:15 UTCApr 18, 01:10 UTC55m
2026-04-17 N201SB - Apr 17, 21:25 UTCApr 17, 21:40 UTC15m
2026-04-14 N201SB - Apr 14, 20:55 UTCApr 14, 21:10 UTC15m
2026-04-14 N201SB - Apr 14, 20:20 UTCApr 14, 20:50 UTC30m
2026-04-14 N201SB - Apr 14, 15:45 UTCApr 14, 16:45 UTC1h 0m

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 N201SB page for operator, model, and routing details .

Mode-S A1974C frequently asked

What is Mode-S code A1974C?
A1974C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N201SB.
Where is Mode-S A1974C registered?
Mode-S code A1974C 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 A1974C broadcasting right now?
No active broadcast right now. Last signal was 4h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1974C, octal 50313514, decimal 10,590,028.
What flights does A1974C operate?
Mode-S A1974C has broadcast 1 distinct callsign, including N201SB.