sensors Mode-S transponder

A7D751

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N604NK · AIRBUS A-320 · operated by BANK OF UTAH TRUSTEE

Hex
A7D751
Octal
51753521
Decimal
10,999,633
Country
US
Tail
N604NK
Type
A320
Photo of N604NK
No current signal · last broadcast 1d ago
Flights observed
3
Distinct callsigns
3
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A7D751.

Country allocation

The ICAO 24-bit address A7D751 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 3 distinct

Callsign Airline Flights Last seen
NKS2191 - 1 2026-04-12
NKS1980 - 1 2026-04-14
NKS1701 - 1 2026-04-13

Recent flights last 3

DateFlightRouteTakeoffLandingDuration
2026-04-14 NKS1980 - Apr 14, 05:15 UTCApr 14, 06:00 UTC45m
2026-04-13 NKS1701 - Apr 13, 00:35 UTCApr 13, 01:50 UTC1h 15m
2026-04-12 NKS2191 - Apr 12, 17:34 UTCApr 12, 19:00 UTC1h 26m

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 N604NK page for operator, model, and routing details .

Mode-S A7D751 frequently asked

What is Mode-S code A7D751?
A7D751 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N604NK.
Where is Mode-S A7D751 registered?
Mode-S code A7D751 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 A7D751 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 A7D751, octal 51753521, decimal 10,999,633.
What flights does A7D751 operate?
Mode-S A7D751 has broadcast 3 distinct callsigns, including NKS2191, NKS1980, NKS1701.