Apparatus

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sensors Mode-S transponder

A2355D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N241SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A2355D
Octal
50432535
Decimal
10,630,493
Country
US
Tail
N241SY
Type
E75L
No current signal · last broadcast 1h ago
Flights observed
582
Distinct callsigns
20
Country
US
Last broadcast
1h ago

Last known position

Most recent position reported by Mode-S A2355D.

Country allocation

The ICAO 24-bit address A2355D 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
SKW3923 - 11 2026-07-12
SKW3755 - 11 2026-07-11
SKW3999 - 10 2026-07-07
SKW3894 - 9 2026-07-05
SKW4155 SkyWest Airlines 8 2026-04-29
SKW3902 - 8 2026-06-26
SKW3883 - 8 2026-06-28
SKW3913 - 7 2026-07-09
SKW3818 SkyWest Airlines 7 2026-07-02
SKW3754 - 7 2026-07-01
SKW4471 - 6 2026-07-12
SKW4144 SkyWest Airlines 6 2026-04-29
SKW4119 - 6 2026-06-26
SKW4077 - 6 2026-06-27
SKW4057 - 6 2026-06-27
SKW3989 SkyWest Airlines 6 2026-06-03
SKW3842 - 6 2026-06-28
SKW3824 - 6 2026-06-20
SKW3707 - 6 2026-07-02
SKW3686 SkyWest Airlines 6 2026-04-28

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 SKW3937 - Jul 14, 02:15 UTCJul 14, 03:15 UTC1h 0m
2026-07-13 SKW3937 SLC → SJC Jul 13, 23:40 UTCJul 14, 01:15 UTC1h 35m
2026-07-13 SKW3801 MFR → SLC Jul 13, 20:50 UTCJul 13, 22:15 UTC1h 25m
2026-07-13 SKW3779 - Jul 13, 18:30 UTCJul 13, 19:40 UTC1h 10m
2026-07-13 SKW3779 SEA → MFR Jul 13, 18:36 UTCJul 13, 19:36 UTC1h 0m
2026-07-13 SKW3695 - Jul 13, 14:50 UTCJul 13, 17:00 UTC2h 10m
2026-07-13 SKW185X - Jul 13, 13:45 UTCJul 13, 14:05 UTC20m
2026-07-13 SKW3932 - Jul 13, 03:40 UTCJul 13, 06:15 UTC2h 35m
2026-07-13 SKW4127 - Jul 13, 01:01 UTCJul 13, 02:20 UTC1h 20m
2026-07-12 SKW4127 - Jul 12, 22:10 UTCJul 12, 23:15 UTC1h 5m
2026-07-12 SKW183T - Jul 12, 18:55 UTCJul 12, 19:55 UTC1h 0m
2026-07-12 SKW3678 - Jul 12, 16:20 UTCJul 12, 17:25 UTC1h 5m
2026-07-12 SKW4471 PDX → SEA Jul 12, 14:10 UTCJul 12, 14:40 UTC30m
2026-07-12 SKW3923 SEA → PDX Jul 12, 02:10 UTCJul 12, 02:40 UTC30m
2026-07-12 SKW3923 SEA → PDX Jul 12, 02:14 UTCJul 12, 02:39 UTC25m
2026-07-12 SKW4165 GEG → SEA Jul 12, 00:05 UTCJul 12, 00:50 UTC45m
2026-07-11 SKW4145 SEA → GEG Jul 11, 21:55 UTCJul 11, 22:30 UTC35m
2026-07-11 SKW3881 - Jul 11, 18:45 UTCJul 11, 19:15 UTC30m
2026-07-11 SKW3881 SMF → SEA Jul 11, 18:50 UTCJul 11, 19:59 UTC1h 9m
2026-07-11 SKW3755 - Jul 11, 16:30 UTCJul 11, 17:30 UTC1h 0m
2026-07-11 SKW3725 - Jul 11, 13:20 UTCJul 11, 15:20 UTC2h 0m
2026-07-11 SKW4090 - Jul 11, 04:35 UTCJul 11, 05:35 UTC1h 0m
2026-07-11 SKW4031 - Jul 11, 01:15 UTCJul 11, 03:20 UTC2h 5m
2026-07-10 SKW4031 SEA → ONT Jul 10, 22:00 UTCJul 11, 00:15 UTC2h 15m
2026-07-10 SKW3881 SMF → SEA Jul 10, 18:50 UTCJul 10, 20:25 UTC1h 35m
2026-07-10 SKW164T SEA → SMF Jul 10, 16:10 UTCJul 10, 17:40 UTC1h 30m
2026-07-10 SKW164T SEA → SMF Jul 10, 15:58 UTCJul 10, 17:36 UTC1h 38m
2026-07-10 SKW4036 - Jul 10, 13:25 UTCJul 10, 14:15 UTC50m
2026-07-10 SKW4036 RDM → SEA Jul 10, 13:34 UTCJul 10, 14:14 UTC40m
2026-07-10 SKW4047 SEA → RDM Jul 10, 05:30 UTCJul 10, 06:20 UTC50m
2026-07-10 SKW4047 SEA → RDM Jul 10, 05:12 UTCJul 10, 06:16 UTC1h 4m
2026-07-10 SKW3832 GEG → SEA Jul 10, 03:15 UTCJul 10, 04:05 UTC50m
2026-07-10 SKW3832 SEA → GEG Jul 10, 01:25 UTCJul 10, 02:00 UTC35m
2026-07-09 SKW3789 SJC → SEA Jul 9, 22:20 UTCJul 10, 00:05 UTC1h 45m
2026-07-09 SKW168F SEA → SJC Jul 9, 19:05 UTCJul 9, 20:55 UTC1h 50m
2026-07-09 SKW168F SEA → SJC Jul 9, 18:55 UTCJul 9, 20:40 UTC1h 45m
2026-07-09 SKW156H GEG → SEA Jul 9, 16:55 UTCJul 9, 17:45 UTC50m
2026-07-09 SKW3830 SEA → GEG Jul 9, 14:50 UTCJul 9, 15:30 UTC40m
2026-07-09 SKW4008 - Jul 9, 12:50 UTCJul 9, 13:20 UTC30m
2026-07-09 SKW3913 SEA → PDX Jul 9, 05:35 UTCJul 9, 06:05 UTC30m
2026-07-09 SKW3913 SEA → PDX Jul 9, 05:31 UTCJul 9, 06:01 UTC30m
2026-07-09 SKW3688 - Jul 9, 03:35 UTCJul 9, 04:40 UTC1h 5m
2026-07-09 SKW3688 - Jul 9, 01:30 UTCJul 9, 02:30 UTC1h 0m
2026-07-08 SKW3679 TUS → SEA Jul 8, 21:25 UTCJul 9, 00:15 UTC2h 50m
2026-07-08 SKW138Y - Jul 8, 17:55 UTCJul 8, 19:25 UTC1h 30m
2026-07-08 SKW3696 - Jul 8, 14:20 UTCJul 8, 16:35 UTC2h 15m
2026-07-08 SKW3576 - Jul 8, 06:10 UTCJul 8, 08:10 UTC2h 0m
2026-07-08 SKW3759 - Jul 8, 03:55 UTCJul 8, 05:00 UTC1h 5m
2026-07-08 SKW3759 - Jul 8, 01:55 UTCJul 8, 02:55 UTC1h 0m
2026-07-07 SKW3822 SJC → LAX Jul 7, 23:35 UTCJul 8, 00:30 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 N241SY page for operator, model, and routing details .

Mode-S A2355D frequently asked

What is Mode-S code A2355D?
A2355D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N241SY.
Where is Mode-S A2355D registered?
Mode-S code A2355D 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 A2355D broadcasting right now?
No active broadcast right now. Last signal was 1h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2355D, octal 50432535, decimal 10,630,493.
What flights does A2355D operate?
Mode-S A2355D has broadcast 20 distinct callsigns, including SKW3923, SKW3755, SKW3999, SKW3894, SKW4155.