Apparatus

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sensors Mode-S transponder

A646BC

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N503SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A646BC
Octal
51443274
Decimal
10,897,084
Country
US
Tail
N503SY
Type
E75L
No current signal · last broadcast Jul 26, 22:20 UTC
Flights observed
623
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:20 UTC

Last known position

Most recent position reported by Mode-S A646BC.

Country allocation

The ICAO 24-bit address A646BC 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
SKW6425 - 22 2026-07-17
SKW6307 SkyWest Airlines 22 2026-07-21
SKW6272 - 18 2026-07-20
SKW6409 - 16 2026-06-25
SKW6510 SkyWest Airlines 15 2026-07-20
SKW6346 SkyWest Airlines 15 2026-07-20
SKW6185 SkyWest Airlines 14 2026-07-21
SKW6381 SkyWest Airlines 13 2026-07-22
SKW6294 SkyWest Airlines 13 2026-07-20
SKW5005 SkyWest Airlines 13 2026-07-17
SKW6190 - 12 2026-07-07
SKW4979 SkyWest Airlines 12 2026-07-20
SKW6393 SkyWest Airlines 11 2026-07-18
SKW6213 SkyWest Airlines 11 2026-05-05
SKW4980 SkyWest Airlines 10 2026-05-11
SKW4975 SkyWest Airlines 10 2026-06-03
SKW4971 - 10 2026-07-13
SKW4951 - 10 2026-07-01
SKW6482 - 9 2026-07-22
SKW6336 - 9 2026-07-07

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW6416 LAX → SFO Jul 26, 16:30 UTCJul 26, 22:15 UTC5h 45m
2026-07-26 SKW4900 LAX → PDX Jul 26, 14:25 UTCJul 26, 14:50 UTC25m
2026-07-26 SKW6370 FAR → ORD Jul 26, 02:29 UTCJul 26, 02:47 UTC18m
2026-07-26 SKW6370 FAR → ORD Jul 26, 02:30 UTCJul 26, 03:00 UTC30m
2026-07-25 SKW4968 LEX → ORD Jul 25, 23:30 UTCJul 26, 00:50 UTC1h 20m
2026-07-25 SKW4968 LEX → ORD Jul 25, 21:10 UTCJul 25, 22:20 UTC1h 10m
2026-07-25 SKW4995 DFW → LAW Jul 25, 18:15 UTCJul 25, 19:20 UTC1h 5m
2026-07-25 SKW4995 DFW → LAW Jul 25, 16:10 UTCJul 25, 17:05 UTC55m
2026-07-25 SKW6360 ORD → LEX Jul 25, 12:30 UTCJul 25, 14:45 UTC2h 15m
2026-07-25 SKW6292 ORD → ICT Jul 25, 03:55 UTCJul 25, 06:00 UTC2h 5m
2026-07-24 SKW4934 PHX → MFR Jul 24, 23:30 UTCJul 25, 01:20 UTC1h 50m
2026-07-24 SKW4934 PHX → MFR Jul 24, 20:50 UTCJul 24, 22:30 UTC1h 40m
2026-07-24 SKW4995 DFW → LAW Jul 24, 18:25 UTCJul 24, 19:25 UTC1h 0m
2026-07-24 SKW4995 DFW → LAW Jul 24, 18:13 UTCJul 24, 19:22 UTC1h 9m
2026-07-24 SKW4995 DFW → LAW Jul 24, 16:15 UTCJul 24, 17:10 UTC55m
2026-07-24 SKW4900 LAX → PDX Jul 24, 14:10 UTCJul 24, 14:40 UTC30m
2026-07-24 SKW4900 LAX → PDX Jul 24, 14:16 UTCJul 24, 14:34 UTC18m
2026-07-24 SKW6370 FAR → ORD Jul 24, 02:15 UTCJul 24, 02:50 UTC35m
2026-07-24 SKW6370 FAR → ORD Jul 24, 02:15 UTCJul 24, 02:44 UTC29m
2026-07-24 SKW6368 PHX → ELP Jul 24, 00:30 UTCJul 24, 00:50 UTC20m
2026-07-24 SKW6368 PHX → ELP Jul 24, 00:30 UTCJul 24, 00:48 UTC18m
2026-07-23 SKW6368 PHX → ELP Jul 23, 23:10 UTCJul 23, 23:40 UTC30m
2026-07-23 SKW4948 YUM → PHX Jul 23, 20:10 UTCJul 23, 22:05 UTC1h 55m
2026-07-23 SKW4948 YUM → PHX Jul 23, 20:09 UTCJul 23, 22:04 UTC1h 55m
2026-07-23 SKW4948 YUM → PHX Jul 23, 17:25 UTCJul 23, 19:05 UTC1h 40m
2026-07-23 SKW4893 YUM → PHX Jul 23, 13:20 UTCJul 23, 15:40 UTC2h 20m
2026-07-23 SKW6224 ABQ → LAX Jul 23, 02:35 UTCJul 23, 05:35 UTC3h 0m
2026-07-22 SKW6381 PHX → SEA Jul 22, 21:00 UTCJul 23, 00:20 UTC3h 20m
2026-07-22 SKW6381 PHX → SEA Jul 22, 16:50 UTCJul 22, 19:50 UTC3h 0m
2026-07-22 SKW6482 - Jul 22, 12:15 UTCJul 22, 15:15 UTC3h 0m
2026-07-22 SKW6187 - Jul 22, 01:05 UTCJul 22, 04:10 UTC3h 5m
2026-07-22 SKW6187 LAX → XNA Jul 22, 01:08 UTCJul 22, 04:09 UTC3h 1m
2026-07-21 SKW6307 DFW → SHV Jul 21, 20:25 UTCJul 21, 23:05 UTC2h 40m
2026-07-21 SKW6307 DFW → SHV Jul 21, 20:23 UTCJul 21, 22:57 UTC2h 34m
2026-07-21 SKW6307 DFW → SHV Jul 21, 16:40 UTCJul 21, 19:10 UTC2h 30m
2026-07-21 SKW6185 SFO → LAX Jul 21, 12:20 UTCJul 21, 14:55 UTC2h 35m
2026-07-20 SKW4979 DFW → MLU Jul 20, 23:45 UTCJul 21, 02:35 UTC2h 50m
2026-07-20 SKW6272 - Jul 20, 19:35 UTCJul 20, 22:00 UTC2h 25m
2026-07-20 SKW6272 LAX → OKC Jul 20, 15:50 UTCJul 20, 18:40 UTC2h 50m
2026-07-20 SKW6294 SFO → LAX Jul 20, 13:20 UTCJul 20, 14:20 UTC1h 0m
2026-07-20 SKW6510 LAX → SFO Jul 20, 05:50 UTCJul 20, 06:50 UTC1h 0m
2026-07-20 SKW6510 LAX → SFO Jul 20, 05:47 UTCJul 20, 06:45 UTC58m
2026-07-20 SKW6346 ORD → BNA Jul 20, 02:30 UTCJul 20, 03:35 UTC1h 5m
2026-07-20 SKW6346 ORD → BNA Jul 20, 00:40 UTCJul 20, 01:40 UTC1h 0m
2026-07-19 SKW6307 DFW → SHV Jul 19, 20:15 UTCJul 19, 22:50 UTC2h 35m
2026-07-19 SKW6307 DFW → SHV Jul 19, 16:35 UTCJul 19, 19:10 UTC2h 35m
2026-07-19 SKW6293 - Jul 19, 11:50 UTCJul 19, 15:05 UTC3h 15m
2026-07-19 SKW5000 - Jul 19, 02:45 UTCJul 19, 06:30 UTC3h 45m
2026-07-19 SKW6221 SFO → LAX Jul 19, 00:03 UTCJul 19, 00:55 UTC52m
2026-07-18 SKW6221 - Jul 18, 23:55 UTCJul 19, 01:05 UTC1h 10m

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 N503SY page for operator, model, and routing details .

Mode-S A646BC frequently asked

What is Mode-S code A646BC?
A646BC is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N503SY.
Where is Mode-S A646BC registered?
Mode-S code A646BC 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 A646BC broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:20 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A646BC, octal 51443274, decimal 10,897,084.
What flights does A646BC operate?
Mode-S A646BC has broadcast 20 distinct callsigns, including SKW6425, SKW6307, SKW6272, SKW6409, SKW6510.