Apparatus

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sensors Mode-S transponder

A309B4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N295SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A309B4
Octal
50604664
Decimal
10,684,852
Country
US
Tail
N295SY
Type
E75L
No current signal · last broadcast Jul 26, 23:00 UTC
Flights observed
701
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 23:00 UTC

Last known position

Most recent position reported by Mode-S A309B4.

Country allocation

The ICAO 24-bit address A309B4 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
SKW4032 - 11 2026-06-19
SKW3989 - 10 2026-07-10
SKW4462 - 9 2026-07-19
SKW4177 SkyWest Airlines 9 2026-07-22
SKW4063 - 9 2026-07-14
SKW3899 - 9 2026-07-12
SKW3526 - 9 2026-07-17
SKW4099 SkyWest Airlines 8 2026-07-25
SKW3935 SkyWest Airlines 8 2026-07-21
SKW3907 SkyWest Airlines 7 2026-07-22
SKW3561 - 7 2026-07-21
SKW197F - 7 2026-07-20
SKW4153 SkyWest Airlines 6 2026-06-03
SKW4068 SkyWest Airlines 6 2026-06-03
SKW4035 - 6 2026-07-12
SKW4015 - 6 2026-07-17
SKW4012 - 6 2026-07-19
SKW3945 SkyWest Airlines 6 2026-07-05
SKW3902 - 6 2026-07-03
SKW3876 - 6 2026-07-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW3707 SJC → SEA Jul 26, 22:00 UTCJul 26, 23:00 UTC1h 0m
2026-07-26 SKW3802 SJC → SEA Jul 26, 19:40 UTCJul 26, 20:10 UTC30m
2026-07-26 SKW3802 SJC → SEA Jul 26, 18:10 UTCJul 26, 18:40 UTC30m
2026-07-26 SKW3740 ORD → JFK Jul 26, 15:15 UTCJul 26, 16:25 UTC1h 10m
2026-07-26 SKW4148 LAX → BOI Jul 26, 03:05 UTCJul 26, 04:25 UTC1h 20m
2026-07-25 SKW3799 MDW → MSP Jul 25, 23:35 UTCJul 26, 02:10 UTC2h 35m
2026-07-25 SKW3794 SJC → SEA Jul 25, 20:40 UTCJul 25, 22:35 UTC1h 55m
2026-07-25 SKW4099 SJC → LAX Jul 25, 18:00 UTCJul 25, 19:05 UTC1h 5m
2026-07-25 SKW4099 SJC → LAX Jul 25, 15:30 UTCJul 25, 16:30 UTC1h 0m
2026-07-25 SKW3743 SEA → SFO Jul 25, 13:40 UTCJul 25, 14:05 UTC25m
2026-07-25 SKW3746 LAX → SAN Jul 25, 06:00 UTCJul 25, 06:35 UTC35m
2026-07-25 SKW3883 MSP → MDW Jul 25, 03:55 UTCJul 25, 04:55 UTC1h 0m
2026-07-25 SKW3883 MSP → MDW Jul 25, 01:25 UTCJul 25, 02:10 UTC45m
2026-07-24 SKW3812 SLC → OAK Jul 24, 21:25 UTCJul 24, 22:35 UTC1h 10m
2026-07-24 SKW134F LAX → SMF Jul 24, 19:25 UTCJul 24, 20:20 UTC55m
2026-07-24 SKW134F LAX → SMF Jul 24, 19:18 UTCJul 24, 20:19 UTC1h 1m
2026-07-24 SKW4451 SEA → SFO Jul 24, 17:00 UTCJul 24, 17:55 UTC55m
2026-07-24 SKW4026 MSP → ATW Jul 24, 14:10 UTCJul 24, 15:45 UTC1h 35m
2026-07-24 SKW3856 SJC → SEA Jul 24, 02:20 UTCJul 24, 03:50 UTC1h 30m
2026-07-23 SKW3856 SJC → SEA Jul 23, 23:50 UTCJul 24, 01:15 UTC1h 25m
2026-07-23 SKW3908 ATL → CRW Jul 23, 20:00 UTCJul 23, 22:30 UTC2h 30m
2026-07-22 SKW3734 LGA → OKC Jul 22, 23:55 UTCJul 23, 02:00 UTC2h 5m
2026-07-22 SKW3734 LGA → OKC Jul 22, 20:05 UTCJul 22, 22:30 UTC2h 25m
2026-07-22 SKW4121 MDW → DTW Jul 22, 17:45 UTCJul 22, 18:35 UTC50m
2026-07-22 SKW4177 AUS → MFE Jul 22, 16:00 UTCJul 22, 16:55 UTC55m
2026-07-22 SKW3950 JFK → IAD Jul 22, 12:20 UTCJul 22, 14:35 UTC2h 15m
2026-07-22 SKW3907 MDW → MSP Jul 22, 03:16 UTCJul 22, 03:39 UTC23m
2026-07-22 SKW3907 MDW → MSP Jul 22, 03:10 UTCJul 22, 03:35 UTC25m
2026-07-21 SKW3935 LAX → SJC Jul 21, 23:15 UTCJul 22, 00:05 UTC50m
2026-07-21 SKW3935 LAX → SJC Jul 21, 20:55 UTCJul 21, 21:45 UTC50m
2026-07-21 SKW3771 MSP → FWA Jul 21, 19:17 UTCJul 21, 19:49 UTC32m
2026-07-21 SKW3771 MSP → FWA Jul 21, 17:45 UTCJul 21, 18:20 UTC35m
2026-07-21 SKW3561 FSD → MSP Jul 21, 16:05 UTCJul 21, 16:45 UTC40m
2026-07-21 SKW3561 MSP → FSD Jul 21, 14:30 UTCJul 21, 15:10 UTC40m
2026-07-21 SKW3996 IAD → MSP Jul 21, 10:10 UTCJul 21, 12:40 UTC2h 30m
2026-07-21 SKW3996 IAD → MSP Jul 21, 10:14 UTCJul 21, 12:29 UTC2h 15m
2026-07-21 SKW4129 HPN → ATL Jul 21, 01:15 UTCJul 21, 03:05 UTC1h 50m
2026-07-20 SKW3686 MSN → MSP Jul 20, 23:55 UTCJul 21, 00:25 UTC30m
2026-07-20 SKW3686 MSN → MSP Jul 20, 22:25 UTCJul 20, 22:45 UTC20m
2026-07-20 SKW157E YWG → MSP Jul 20, 18:15 UTCJul 20, 19:15 UTC1h 0m
2026-07-20 SKW157E YWG → MSP Jul 20, 18:20 UTCJul 20, 19:15 UTC55m
2026-07-20 SKW197F MSP → YWG Jul 20, 15:49 UTCJul 20, 16:40 UTC51m
2026-07-20 SKW197F MSP → YWG Jul 20, 15:35 UTCJul 20, 16:45 UTC1h 10m
2026-07-20 SKW4458 - Jul 20, 13:10 UTCJul 20, 14:15 UTC1h 5m
2026-07-20 SKW4468 MSP → MKE Jul 20, 01:45 UTCJul 20, 02:35 UTC50m
2026-07-19 SKW4012 - Jul 19, 22:25 UTCJul 19, 23:55 UTC1h 30m
2026-07-19 SKW4012 MSP → XNA Jul 19, 19:50 UTCJul 19, 21:15 UTC1h 25m
2026-07-19 SKW3699 IAD → MSP Jul 19, 15:55 UTCJul 19, 18:15 UTC2h 20m
2026-07-19 SKW3699 MSP → IAD Jul 19, 12:35 UTCJul 19, 14:30 UTC1h 55m
2026-07-19 SKW3914 - Jul 19, 10:25 UTCJul 19, 11:10 UTC45m

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 N295SY page for operator, model, and routing details .

Mode-S A309B4 frequently asked

What is Mode-S code A309B4?
A309B4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N295SY.
Where is Mode-S A309B4 registered?
Mode-S code A309B4 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 A309B4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 23:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A309B4, octal 50604664, decimal 10,684,852.
What flights does A309B4 operate?
Mode-S A309B4 has broadcast 20 distinct callsigns, including SKW4032, SKW3989, SKW4462, SKW4177, SKW4063.