sensors Mode-S transponder

A1A9F4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N206SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A1A9F4
Octal
50324764
Decimal
10,594,804
Country
US
Tail
N206SY
Type
E75L
No current signal · last broadcast 19h ago
Flights observed
13
Distinct callsigns
9
Country
US
Last broadcast
19h ago

Last known position

Most recent position reported by Mode-S A1A9F4.

Country allocation

The ICAO 24-bit address A1A9F4 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 9 distinct

Callsign Airline Flights Last seen
SKW5662 - 3 2026-04-14
SKW5369 - 2 2026-04-13
SKW4686 - 2 2026-04-13
SKW6041 - 1 2026-04-12
SKW6006 - 1 2026-04-14
SKW5651 - 1 2026-04-13
SKW5311 - 1 2026-04-12
SKW4754 - 1 2026-04-13
SKW4660 - 1 2026-04-13

Recent flights last 13

DateFlightRouteTakeoffLandingDuration
2026-04-14 SKW5662 - Apr 14, 09:10 UTCApr 14, 10:00 UTC50m
2026-04-14 SKW5662 - Apr 14, 07:10 UTCApr 14, 09:05 UTC1h 55m
2026-04-14 SKW5662 - Apr 14, 06:34 UTCApr 14, 09:53 UTC3h 19m
2026-04-14 SKW6006 - Apr 14, 05:15 UTCApr 14, 05:55 UTC40m
2026-04-13 SKW5651 - Apr 13, 22:10 UTCApr 13, 23:45 UTC1h 35m
2026-04-13 SKW4686 - Apr 13, 19:50 UTCApr 13, 20:30 UTC40m
2026-04-13 SKW4686 - Apr 13, 18:45 UTCApr 13, 20:10 UTC1h 25m
2026-04-13 SKW5369 - Apr 13, 16:15 UTCApr 13, 17:15 UTC1h 0m
2026-04-13 SKW5369 - Apr 13, 15:45 UTCApr 13, 16:15 UTC30m
2026-04-13 SKW4660 - Apr 13, 13:25 UTCApr 13, 14:05 UTC40m
2026-04-13 SKW4754 - Apr 13, 01:55 UTCApr 13, 02:35 UTC40m
2026-04-12 SKW5311 - Apr 12, 19:53 UTCApr 12, 21:20 UTC1h 27m
2026-04-12 SKW6041 - Apr 12, 16:46 UTCApr 12, 18:17 UTC1h 31m

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 N206SY page for operator, model, and routing details .

Mode-S A1A9F4 frequently asked

What is Mode-S code A1A9F4?
A1A9F4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N206SY.
Where is Mode-S A1A9F4 registered?
Mode-S code A1A9F4 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 A1A9F4 broadcasting right now?
No active broadcast right now. Last signal was 19h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1A9F4, octal 50324764, decimal 10,594,804.
What flights does A1A9F4 operate?
Mode-S A1A9F4 has broadcast 9 distinct callsigns, including SKW5662, SKW5369, SKW4686, SKW6041, SKW6006.