sensors Mode-S transponder

A1954B

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N20067 · CESSNA 172 Skyhawk · operated by MCCLEAN MATTHEW J

Hex
A1954B
Octal
50312513
Decimal
10,589,515
Country
US
Tail
N20067
Type
C172
No current signal · last broadcast 1d ago
Flights observed
8
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A1954B.

Country allocation

The ICAO 24-bit address A1954B 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
N20065 - 8 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 N20065 - Apr 13, 17:25 UTCApr 13, 18:35 UTC1h 10m
2026-04-13 N20065 - Apr 13, 16:15 UTCApr 13, 16:35 UTC20m
2026-04-13 N20065 - Apr 13, 15:50 UTCApr 13, 16:35 UTC45m
2026-04-13 N20065 - Apr 13, 15:40 UTCApr 13, 16:15 UTC35m
2026-04-13 N20065 - Apr 13, 13:45 UTCApr 13, 14:55 UTC1h 10m
2026-04-13 N20065 - Apr 13, 12:20 UTCApr 13, 12:45 UTC25m
2026-04-13 N20065 - Apr 13, 11:55 UTCApr 13, 12:45 UTC50m
2026-04-13 N20065 - Apr 13, 11:40 UTCApr 13, 12:15 UTC35m

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 N20067 page for operator, model, and routing details .

Mode-S A1954B frequently asked

What is Mode-S code A1954B?
A1954B is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N20067.
Where is Mode-S A1954B registered?
Mode-S code A1954B 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 A1954B 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 A1954B, octal 50312513, decimal 10,589,515.
What flights does A1954B operate?
Mode-S A1954B has broadcast 1 distinct callsign, including N20065.