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sensors Mode-S transponder

A851F6

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N635SY · operated by SKYWEST AIRLINES INC

Hex
A851F6
Octal
52050766
Decimal
11,031,030
Country
US
Tail
N635SY
Broadcasting now · callsign SKW4676 · 2,950 ft
Flights observed
589
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 15:40 UTC

Current position

A851F6 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A851F6 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
SKW5769 - 11 2026-07-18
SKW5774 SkyWest Airlines 10 2026-07-18
SKW5493 SkyWest Airlines 9 2026-07-25
SKW5917 SkyWest Airlines 8 2026-07-25
SKW5771 - 8 2026-06-20
SKW769W - 7 2026-07-14
SKW5780 - 7 2026-07-14
SKW5520 SkyWest Airlines 7 2026-07-20
SKW5814 SkyWest Airlines 6 2026-07-21
SKW5776 SkyWest Airlines 6 2026-06-21
SKW5775 SkyWest Airlines 6 2026-06-21
SKW5766 SkyWest Airlines 6 2026-06-06
SKW5632 SkyWest Airlines 6 2026-04-29
SKW5560 - 6 2026-06-18
SKW5418 - 6 2026-06-18
SKW5300 SkyWest Airlines 6 2026-07-26
SKW4761 - 6 2026-07-18
SKW5772 - 5 2026-06-20
SKW5749 SkyWest Airlines 5 2026-07-20
SKW5529 SkyWest Airlines 5 2026-07-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW5300 LCH → IAH Jul 26, 13:30 UTCJul 26, 15:40 UTC2h 10m
2026-07-25 SKW5917 SFO → SEA Jul 25, 22:05 UTCJul 25, 23:55 UTC1h 50m
2026-07-25 SKW5493 SMF → SFO Jul 25, 18:35 UTCJul 25, 20:40 UTC2h 5m
2026-07-25 SKW5493 SMF → SFO Jul 25, 18:29 UTCJul 25, 20:40 UTC2h 11m
2026-07-25 SKW5279 DEN → FSD Jul 25, 14:50 UTCJul 25, 17:00 UTC2h 10m
2026-07-25 SKW5611 SFO → ONT Jul 25, 11:20 UTCJul 25, 12:35 UTC1h 15m
2026-07-24 SKW5777 SBP → SFO Jul 24, 23:35 UTCJul 25, 00:40 UTC1h 5m
2026-07-24 SKW4669 ACV → SFO Jul 24, 15:20 UTCJul 24, 17:30 UTC2h 10m
2026-07-24 SKW4669 ACV → SFO Jul 24, 15:25 UTCJul 24, 17:31 UTC2h 6m
2026-07-24 SKW5254 EUG → SFO Jul 24, 01:40 UTCJul 24, 03:50 UTC2h 10m
2026-07-23 SKW5264 TUS → SFO Jul 23, 22:30 UTCJul 23, 23:15 UTC45m
2026-07-23 SKW5264 TUS → SFO Jul 23, 22:41 UTCJul 23, 23:26 UTC45m
2026-07-23 SKW5867 OKC → ORD Jul 23, 20:40 UTCJul 23, 21:25 UTC45m
2026-07-23 SKW5867 OKC → ORD Jul 23, 20:37 UTCJul 23, 21:25 UTC48m
2026-07-23 SKW5447 MFR → SFO Jul 23, 17:50 UTCJul 23, 18:15 UTC25m
2026-07-23 SKW5447 MFR → SFO Jul 23, 17:40 UTCJul 23, 18:17 UTC37m
2026-07-23 SKW318J - Jul 23, 16:10 UTCJul 23, 16:35 UTC25m
2026-07-22 SKW6000 HPN → ORD Jul 22, 23:35 UTCJul 22, 23:40 UTC5m
2026-07-22 SKW6000 HPN → ORD Jul 22, 22:05 UTCJul 22, 23:40 UTC1h 35m
2026-07-22 SKW6000 HPN → ORD Jul 22, 22:07 UTCJul 22, 23:16 UTC1h 9m
2026-07-22 SKW725M ORD → TYS Jul 22, 19:40 UTCJul 22, 20:50 UTC1h 10m
2026-07-22 SKW5823 OKC → ORD Jul 22, 15:35 UTCJul 22, 17:10 UTC1h 35m
2026-07-22 SKW5193 CRW → ORD Jul 22, 12:45 UTCJul 22, 14:25 UTC1h 40m
2026-07-22 SKW5956 ASE → ORD Jul 22, 01:50 UTCJul 22, 03:50 UTC2h 0m
2026-07-22 SKW5956 ASE → ORD Jul 22, 01:46 UTCJul 22, 03:34 UTC1h 48m
2026-07-21 SKW5814 RNO → SFO Jul 21, 15:05 UTCJul 21, 16:55 UTC1h 50m
2026-07-21 SKW5814 RNO → SFO Jul 21, 15:10 UTCJul 21, 17:11 UTC2h 1m
2026-07-21 SKW5259 - Jul 21, 13:15 UTCJul 21, 13:55 UTC40m
2026-07-21 SKW376Z - Jul 21, 00:20 UTCJul 21, 02:10 UTC1h 50m
2026-07-20 SKW5749 PIT → ORD Jul 20, 22:25 UTCJul 20, 22:55 UTC30m
2026-07-20 SKW342F - Jul 20, 20:45 UTCJul 20, 21:05 UTC20m
2026-07-20 SKW5520 OKC → IAH Jul 20, 16:10 UTCJul 20, 18:05 UTC1h 55m
2026-07-20 SKW5529 LAX → RDD Jul 20, 02:15 UTCJul 20, 04:10 UTC1h 55m
2026-07-19 SKW5694 GRB → ORD Jul 19, 22:50 UTCJul 20, 00:15 UTC1h 25m
2026-07-19 SKW5641 DEN → XNA Jul 19, 20:28 UTCJul 19, 21:58 UTC1h 30m
2026-07-19 SKW5641 DEN → XNA Jul 19, 20:25 UTCJul 19, 21:45 UTC1h 20m
2026-07-19 SKW5520 CLD → DEN Jul 19, 15:55 UTCJul 19, 18:00 UTC2h 5m
2026-07-19 SKW5529 DEN → CLD Jul 19, 01:45 UTCJul 19, 04:15 UTC2h 30m
2026-07-18 SKW5778 - Jul 18, 23:35 UTCJul 18, 23:55 UTC20m
2026-07-18 SKW5773 - Jul 18, 22:15 UTCJul 18, 22:30 UTC15m
2026-07-18 SKW5774 ASE → DEN Jul 18, 19:45 UTCJul 18, 20:10 UTC25m
2026-07-18 SKW5769 - Jul 18, 17:55 UTCJul 18, 18:10 UTC15m
2026-07-18 SKW4659 ABQ → DEN Jul 18, 15:10 UTCJul 18, 16:15 UTC1h 5m
2026-07-18 SKW4659 ABQ → DEN Jul 18, 15:11 UTCJul 18, 16:10 UTC59m
2026-07-18 SKW4761 DEN → ABQ Jul 18, 03:30 UTCJul 18, 04:25 UTC55m
2026-07-18 SKW4761 DEN → ABQ Jul 18, 03:29 UTCJul 18, 04:22 UTC53m
2026-07-18 SKW5736 SLC → SFO Jul 18, 00:06 UTCJul 18, 01:41 UTC1h 35m
2026-07-17 SKW6030 ORD → CHO Jul 17, 21:30 UTCJul 18, 02:00 UTC4h 30m
2026-07-17 SKW5774 ASE → DEN Jul 17, 19:20 UTCJul 17, 19:45 UTC25m
2026-07-17 SKW5774 ASE → DEN Jul 17, 19:23 UTCJul 17, 19:44 UTC21m

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 N635SY page for operator, model, and routing details .

Mode-S A851F6 frequently asked

What is Mode-S code A851F6?
A851F6 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N635SY.
Where is Mode-S A851F6 registered?
Mode-S code A851F6 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 A851F6 broadcasting right now?
Yes. Mode-S A851F6 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A851F6, octal 52050766, decimal 11,031,030.
What flights does A851F6 operate?
Mode-S A851F6 has broadcast 20 distinct callsigns, including SKW5769, SKW5774, SKW5493, SKW5917, SKW5771.