sensors Mode-S transponder

A1EEF8

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N2233S · CESSNA 201 Centurion · operated by RICHARDSON ROBERT O, RICHARDSON GEORGE G

Hex
A1EEF8
Octal
50367370
Decimal
10,612,472
Country
US
Tail
N2233S
Type
C210
No current signal · last broadcast 1d ago
Flights observed
5
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A1EEF8.

Country allocation

The ICAO 24-bit address A1EEF8 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
N2233S - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 N2233S - Apr 13, 18:25 UTCApr 13, 18:55 UTC30m
2026-04-13 N2233S - Apr 13, 03:10 UTCApr 13, 03:30 UTC20m
2026-04-13 N2233S - Apr 13, 01:45 UTCApr 13, 01:55 UTC10m
2026-04-12 N2233S - Apr 12, 19:15 UTCApr 12, 20:15 UTC1h 0m
2026-04-12 N2233S - Apr 12, 17:15 UTCApr 12, 18:05 UTC50m

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 N2233S page for operator, model, and routing details .

Mode-S A1EEF8 frequently asked

What is Mode-S code A1EEF8?
A1EEF8 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N2233S.
Where is Mode-S A1EEF8 registered?
Mode-S code A1EEF8 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 A1EEF8 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 A1EEF8, octal 50367370, decimal 10,612,472.
What flights does A1EEF8 operate?
Mode-S A1EEF8 has broadcast 1 distinct callsign, including N2233S.