sensors Mode-S transponder

AD4F81

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N957JS · CESSNA 750 Citation 10 · operated by CITATION X PARTS LLC

Hex
AD4F81
Octal
53247601
Decimal
11,358,081
Country
US
Tail
N957JS
Type
C750
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 AD4F81.

Country allocation

The ICAO 24-bit address AD4F81 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
KOW957 - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 KOW957 - Apr 13, 16:15 UTCApr 13, 17:15 UTC1h 0m
2026-04-13 KOW957 - Apr 13, 15:50 UTCApr 13, 17:15 UTC1h 25m
2026-04-13 KOW957 - Apr 13, 14:40 UTCApr 13, 16:15 UTC1h 35m
2026-04-13 KOW957 - Apr 13, 00:20 UTCApr 13, 01:00 UTC40m
2026-04-12 KOW957 - Apr 12, 23:55 UTCApr 13, 01:00 UTC1h 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 N957JS page for operator, model, and routing details .

Mode-S AD4F81 frequently asked

What is Mode-S code AD4F81?
AD4F81 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N957JS.
Where is Mode-S AD4F81 registered?
Mode-S code AD4F81 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 AD4F81 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 AD4F81, octal 53247601, decimal 11,358,081.
What flights does AD4F81 operate?
Mode-S AD4F81 has broadcast 1 distinct callsign, including KOW957.