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sensors Mode-S transponder

A8431A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N631SY · operated by SKYWEST AIRLINES INC

Hex
A8431A
Octal
52041432
Decimal
11,027,226
Country
US
Tail
N631SY
Type
E75L
No current signal · last broadcast Jul 26, 21:35 UTC
Flights observed
694
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:35 UTC

Last known position

Most recent position reported by Mode-S A8431A.

Country allocation

The ICAO 24-bit address A8431A 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 20 distinct

Callsign Airline Flights Last seen
SKW5782 SkyWest Airlines 11 2026-07-23
SKW5772 SkyWest Airlines 10 2026-07-23
SKW5766 SkyWest Airlines 10 2026-07-23
SKW5749 - 10 2026-07-09
SKW5956 SkyWest Airlines 9 2026-07-24
SKW5779 - 9 2026-07-13
SKW4669 SkyWest Airlines 9 2026-07-25
SKW4646 SkyWest Airlines 8 2026-06-15
SKW6008 - 7 2026-07-06
SKW5917 SkyWest Airlines 7 2026-07-22
SKW5780 SkyWest Airlines 7 2026-06-06
SKW5775 - 7 2026-06-30
SKW5493 - 7 2026-07-22
SKW5254 SkyWest Airlines 7 2026-07-25
SKW5802 SkyWest Airlines 6 2026-04-28
SKW5778 - 6 2026-07-08
SKW5776 SkyWest Airlines 6 2026-07-23
SKW5774 - 6 2026-07-08
SKW5771 SkyWest Airlines 6 2026-07-23
SKW5667 - 6 2026-07-02

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW5311 ORD → DCA Jul 26, 20:20 UTCJul 26, 21:35 UTC1h 15m
2026-07-26 SKW5276 DCA → ORD Jul 26, 17:10 UTCJul 26, 18:35 UTC1h 25m
2026-07-26 SKW5795 ORD → TUL Jul 26, 14:35 UTCJul 26, 15:55 UTC1h 20m
2026-07-26 SKW5795 ORD → TUL Jul 26, 14:16 UTCJul 26, 15:51 UTC1h 35m
2026-07-26 SKW5611 SFO → ONT Jul 26, 11:15 UTCJul 26, 12:25 UTC1h 10m
2026-07-26 SKW5611 SFO → ONT Jul 26, 11:23 UTCJul 26, 12:19 UTC56m
2026-07-26 SKW5777 SBP → SFO Jul 26, 01:25 UTCJul 26, 02:30 UTC1h 5m
2026-07-26 SKW5777 SBP → SFO Jul 26, 01:28 UTCJul 26, 02:29 UTC1h 1m
2026-07-25 SKW5524 SFO → ONT Jul 25, 22:05 UTCJul 25, 23:50 UTC1h 45m
2026-07-25 SKW5403 LGA → ORD Jul 25, 19:30 UTCJul 25, 20:50 UTC1h 20m
2026-07-25 SKW4669 ACV → SFO Jul 25, 15:15 UTCJul 25, 17:30 UTC2h 15m
2026-07-25 SKW5254 EUG → SFO Jul 25, 01:20 UTCJul 25, 03:30 UTC2h 10m
2026-07-25 SKW5254 EUG → SFO Jul 25, 01:24 UTCJul 25, 03:40 UTC2h 16m
2026-07-24 SKW5956 ASE → ORD Jul 24, 19:00 UTCJul 24, 21:00 UTC2h 0m
2026-07-24 SKW5814 RNO → SFO Jul 24, 15:15 UTCJul 24, 17:45 UTC2h 30m
2026-07-24 SKW5259 ICT → ORD Jul 24, 12:35 UTCJul 24, 13:15 UTC40m
2026-07-24 SKW376Z DEN → SHV Jul 24, 01:00 UTCJul 24, 02:55 UTC1h 55m
2026-07-24 SKW376Z DEN → SHV Jul 24, 01:07 UTCJul 24, 02:43 UTC1h 36m
2026-07-23 SKW5776 JAC → SFO Jul 23, 23:20 UTCJul 23, 23:45 UTC25m
2026-07-23 SKW5771 RDM → DEN Jul 23, 21:45 UTCJul 23, 21:55 UTC10m
2026-07-23 SKW5772 ASE → DEN Jul 23, 19:45 UTCJul 23, 20:05 UTC20m
2026-07-23 SKW5782 DEN → ASE Jul 23, 17:45 UTCJul 23, 18:15 UTC30m
2026-07-23 SKW5766 ASE → DEN Jul 23, 13:55 UTCJul 23, 14:20 UTC25m
2026-07-23 SKW5766 ASE → DEN Jul 23, 14:00 UTCJul 23, 14:17 UTC17m
2026-07-22 SKW5917 SFO → SEA Jul 22, 22:30 UTCJul 23, 00:30 UTC2h 0m
2026-07-22 SKW5493 - Jul 22, 18:15 UTCJul 22, 20:25 UTC2h 10m
2026-07-22 SKW5279 DEN → FSD Jul 22, 14:15 UTCJul 22, 16:25 UTC2h 10m
2026-07-22 SKW5902 SFO → GEG Jul 22, 11:55 UTCJul 22, 12:30 UTC35m
2026-07-22 SKW5768 - Jul 22, 01:30 UTCJul 22, 02:00 UTC30m
2026-07-21 SKW5435 - Jul 21, 23:30 UTCJul 22, 00:15 UTC45m
2026-07-21 SKW5985 DEN → BHM Jul 21, 22:15 UTCJul 21, 22:45 UTC30m
2026-07-21 SKW5985 DEN → BHM Jul 21, 22:06 UTCJul 21, 22:44 UTC38m
2026-07-21 SKW4653 DEN → DAY Jul 21, 19:00 UTCJul 21, 20:30 UTC1h 30m
2026-07-21 SKW4653 DEN → DAY Jul 21, 18:52 UTCJul 21, 20:13 UTC1h 21m
2026-07-21 SKW5197 BNA → ORD Jul 21, 16:55 UTCJul 21, 17:55 UTC1h 0m
2026-07-21 SKW5197 BNA → ORD Jul 21, 16:35 UTCJul 21, 17:53 UTC1h 18m
2026-07-20 SKW5450 SMF → SFO Jul 20, 00:15 UTCJul 20, 01:50 UTC1h 35m
2026-07-19 SKW5552 BUR → SFO Jul 19, 21:25 UTCJul 19, 23:05 UTC1h 40m
2026-07-19 SKW5570 - Jul 19, 18:30 UTCJul 19, 19:25 UTC55m
2026-07-19 SKW5570 MSP → ORD Jul 19, 18:25 UTCJul 19, 19:11 UTC46m
2026-07-19 SKW5684 ORD → MSP Jul 19, 16:05 UTCJul 19, 16:48 UTC43m
2026-07-19 SKW5684 ORD → MSP Jul 19, 15:50 UTCJul 19, 17:00 UTC1h 10m
2026-07-19 SKW4803 BUR → SFO Jul 19, 13:05 UTCJul 19, 13:45 UTC40m
2026-07-19 SKW4803 BUR → SFO Jul 19, 13:09 UTCJul 19, 13:26 UTC17m
2026-07-19 SKW5362 ORD → PIA Jul 19, 02:50 UTCJul 19, 03:10 UTC20m
2026-07-18 SKW5450 SMF → SFO Jul 18, 21:30 UTCJul 19, 00:30 UTC3h 0m
2026-07-18 SKW6013 MKE → ORD Jul 18, 15:10 UTCJul 18, 17:55 UTC2h 45m
2026-07-18 SKW5265 - Jul 18, 10:15 UTCJul 18, 10:30 UTC15m
2026-07-18 SKW5265 CLE → ORD Jul 18, 10:23 UTCJul 18, 11:19 UTC56m
2026-07-17 SKW5638 - Jul 17, 21:44 UTCJul 17, 22:40 UTC55m

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 N631SY page for operator, model, and routing details .

Mode-S A8431A frequently asked

What is Mode-S code A8431A?
A8431A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N631SY.
Where is Mode-S A8431A registered?
Mode-S code A8431A 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 A8431A broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:35 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A8431A, octal 52041432, decimal 11,027,226.
What flights does A8431A operate?
Mode-S A8431A has broadcast 20 distinct callsigns, including SKW5782, SKW5772, SKW5766, SKW5749, SKW5956.