sensors Mode-S transponder

A860D2

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N639SY · operated by SKYWEST AIRLINES INC

Hex
A860D2
Octal
52060322
Decimal
11,034,834
Country
US
Tail
N639SY
No current signal · last broadcast 6h ago
Flights observed
15
Distinct callsigns
10
Country
US
Last broadcast
6h ago

Last known position

Most recent position reported by Mode-S A860D2.

Country allocation

The ICAO 24-bit address A860D2 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 10 distinct

Callsign Airline Flights Last seen
N639SY - 3 2026-06-28
SKW6080 - 2 2026-07-12
SKW5273 - 2 2026-07-12
SKW4773 - 2 2026-07-13
SKW6020 - 1 2026-07-13
SKW5810 - 1 2026-07-13
SKW5777 - 1 2026-07-14
SKW5677 - 1 2026-07-12
SKW4716 - 1 2026-07-13
SKW0639 - 1 2026-06-28

Recent flights last 15

DateFlightRouteTakeoffLandingDuration
2026-07-14 SKW5777 - Jul 14, 00:00 UTCJul 14, 01:00 UTC1h 0m
2026-07-13 SKW5810 - Jul 13, 16:15 UTCJul 13, 17:50 UTC1h 35m
2026-07-13 SKW6020 DEN → ICT Jul 13, 14:15 UTCJul 13, 15:20 UTC1h 5m
2026-07-13 SKW4716 - Jul 13, 10:40 UTCJul 13, 12:15 UTC1h 35m
2026-07-13 SKW4773 DEN → CID Jul 13, 02:55 UTCJul 13, 04:30 UTC1h 35m
2026-07-13 SKW4773 DEN → CID Jul 13, 02:53 UTCJul 13, 04:26 UTC1h 33m
2026-07-12 SKW5273 CID → DEN Jul 12, 23:45 UTCJul 13, 01:20 UTC1h 35m
2026-07-12 SKW5273 CID → DEN Jul 12, 23:26 UTCJul 13, 01:14 UTC1h 48m
2026-07-12 SKW5677 DEN → CID Jul 12, 20:30 UTCJul 12, 22:00 UTC1h 30m
2026-07-12 SKW6080 - Jul 12, 13:40 UTCJul 12, 15:10 UTC1h 30m
2026-07-12 SKW6080 BOI → DEN Jul 12, 13:19 UTCJul 12, 15:08 UTC1h 49m
2026-06-28 SKW0639 - Jun 28, 17:19 UTCJun 28, 19:59 UTC2h 40m
2026-06-28 N639SY - Jun 28, 12:09 UTCJun 28, 16:29 UTC4h 20m
2026-06-27 N639SY - Jun 27, 19:34 UTCJun 27, 19:55 UTC20m
2026-06-27 N639SY - Jun 27, 11:30 UTCJun 27, 18:35 UTC7h 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 N639SY page for operator, model, and routing details .

Mode-S A860D2 frequently asked

What is Mode-S code A860D2?
A860D2 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N639SY.
Where is Mode-S A860D2 registered?
Mode-S code A860D2 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 A860D2 broadcasting right now?
No active broadcast right now. Last signal was 6h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A860D2, octal 52060322, decimal 11,034,834.
What flights does A860D2 operate?
Mode-S A860D2 has broadcast 10 distinct callsigns, including N639SY, SKW6080, SKW5273, SKW4773, SKW6020.