sensors Mode-S transponder

A6594F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N508SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A6594F
Octal
51454517
Decimal
10,901,839
Country
US
Tail
N508SY
Type
E75L
Transponder active on ground
Flights observed
6
Distinct callsigns
3
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A6594F.

Country allocation

The ICAO 24-bit address A6594F 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
SKW4985 SkyWest Airlines 4 2026-04-13
SKW6392 SkyWest Airlines 1 2026-04-12
SKW6386 - 1 2026-04-12

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-13 SKW4985 SJC → PHX Apr 13, 19:50 UTCApr 13, 23:05 UTC3h 15m
2026-04-13 SKW4985 SJC → PHX Apr 13, 19:47 UTCApr 13, 22:52 UTC3h 5m
2026-04-13 SKW4985 SJC → PHX Apr 13, 16:24 UTCApr 13, 18:50 UTC2h 26m
2026-04-13 SKW4985 SJC → PHX Apr 13, 16:00 UTCApr 13, 16:15 UTC15m
2026-04-12 SKW6386 - Apr 12, 19:10 UTCApr 12, 20:15 UTC1h 5m
2026-04-12 SKW6392 OKC → PHX Apr 12, 17:15 UTCApr 12, 18:15 UTC1h 0m

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 N508SY page for operator, model, and routing details .

Mode-S A6594F frequently asked

What is Mode-S code A6594F?
A6594F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N508SY.
Where is Mode-S A6594F registered?
Mode-S code A6594F 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 A6594F broadcasting right now?
Mode-S A6594F is currently broadcasting from the ground.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A6594F, octal 51454517, decimal 10,901,839.
What flights does A6594F operate?
Mode-S A6594F has broadcast 3 distinct callsigns, including SKW4985, SKW6392, SKW6386.