sensors Mode-S transponder

ADF45A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N999CX · CESSNA 560XL Citation XLS · operated by BIG SKY AVIATION LLC

Hex
ADF45A
Octal
53372132
Decimal
11,400,282
Country
US
Tail
N999CX
Type
C56X
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 ADF45A.

Country allocation

The ICAO 24-bit address ADF45A 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
EJM999 - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 EJM999 - Apr 13, 21:30 UTCApr 13, 22:55 UTC1h 25m
2026-04-13 EJM999 - Apr 13, 19:50 UTCApr 13, 20:00 UTC10m
2026-04-13 EJM999 - Apr 13, 16:15 UTCApr 13, 20:00 UTC3h 45m
2026-04-12 EJM999 - Apr 12, 20:05 UTCApr 12, 20:15 UTC10m
2026-04-12 EJM999 - Apr 12, 17:15 UTCApr 12, 19:20 UTC2h 5m

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 N999CX page for operator, model, and routing details .

Mode-S ADF45A frequently asked

What is Mode-S code ADF45A?
ADF45A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N999CX.
Where is Mode-S ADF45A registered?
Mode-S code ADF45A 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 ADF45A 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 ADF45A, octal 53372132, decimal 11,400,282.
What flights does ADF45A operate?
Mode-S ADF45A has broadcast 1 distinct callsign, including EJM999.