Apparatus

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sensors Mode-S transponder

A3539D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N313SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A3539D
Octal
50651635
Decimal
10,703,773
Country
US
Tail
N313SY
Type
E75L
Broadcasting now · callsign SKW197F · 6,800 ft
Flights observed
698
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:10 UTC

Current position

A3539D is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A3539D 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
SKW4101 - 10 2026-07-10
SKW3876 - 10 2026-07-11
SKW3620 - 9 2026-06-23
SKW3577 SkyWest Airlines 9 2026-06-27
SKW4091 SkyWest Airlines 8 2026-06-10
SKW3660 SkyWest Airlines 8 2026-07-25
SKW3945 SkyWest Airlines 7 2026-06-28
SKW3935 SkyWest Airlines 7 2026-07-24
SKW3822 SkyWest Airlines 7 2026-06-12
SKW3798 - 7 2026-07-19
SKW135K SkyWest Airlines 7 2026-07-25
SKW4099 SkyWest Airlines 6 2026-06-07
SKW4043 SkyWest Airlines 6 2026-06-13
SKW4028 - 6 2026-07-09
SKW3974 SkyWest Airlines 6 2026-05-16
SKW3966 SkyWest Airlines 6 2026-06-13
SKW3952 - 6 2026-07-09
SKW3951 SkyWest Airlines 6 2026-06-11
SKW3841 - 6 2026-07-22
SKW3828 SkyWest Airlines 6 2026-07-23

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW3686 MSN → MSP Jul 26, 19:50 UTCJul 26, 20:10 UTC20m
2026-07-26 SKW3699 OMA → LGA Jul 26, 15:45 UTCJul 26, 18:05 UTC2h 20m
2026-07-26 SKW3699 OMA → LGA Jul 26, 12:35 UTCJul 26, 14:30 UTC1h 55m
2026-07-26 SKW3914 SEA → SMF Jul 26, 10:15 UTCJul 26, 11:05 UTC50m
2026-07-26 SKW3834 GTF → MSP Jul 26, 02:45 UTCJul 26, 03:45 UTC1h 0m
2026-07-25 SKW3851 LAX → SJC Jul 25, 23:25 UTCJul 26, 00:35 UTC1h 10m
2026-07-25 SKW3851 LAX → SJC Jul 25, 19:55 UTCJul 25, 20:55 UTC1h 0m
2026-07-25 SKW157E DTW → OMA Jul 25, 18:00 UTCJul 25, 19:00 UTC1h 0m
2026-07-25 SKW197F MSP → YWG Jul 25, 15:24 UTCJul 25, 16:12 UTC48m
2026-07-25 SKW197F MSP → YWG Jul 25, 15:05 UTCJul 25, 16:20 UTC1h 15m
2026-07-25 SKW3660 MSP → YYZ Jul 25, 11:55 UTCJul 25, 12:55 UTC1h 0m
2026-07-25 SKW3660 MSP → YYZ Jul 25, 11:59 UTCJul 25, 12:49 UTC50m
2026-07-25 SKW135K LAX → SJC Jul 25, 03:10 UTCJul 25, 04:20 UTC1h 10m
2026-07-24 SKW3935 LAX → SJC Jul 24, 23:05 UTCJul 24, 23:50 UTC45m
2026-07-24 SKW3935 LAX → SJC Jul 24, 20:40 UTCJul 24, 21:35 UTC55m
2026-07-24 SKW3989 PHX → LAX Jul 24, 17:15 UTCJul 24, 19:05 UTC1h 50m
2026-07-24 SKW3989 PHX → LAX Jul 24, 14:40 UTCJul 24, 16:10 UTC1h 30m
2026-07-24 SKW3660 MSP → YYZ Jul 24, 12:00 UTCJul 24, 13:00 UTC1h 0m
2026-07-24 SKW135K LAX → SJC Jul 24, 03:15 UTCJul 24, 04:25 UTC1h 10m
2026-07-23 SKW3935 LAX → SJC Jul 23, 23:45 UTCJul 24, 00:35 UTC50m
2026-07-23 SKW3935 LAX → SJC Jul 23, 23:36 UTCJul 24, 00:28 UTC52m
2026-07-23 SKW3935 LAX → SJC Jul 23, 21:25 UTCJul 23, 22:15 UTC50m
2026-07-23 SKW3848 SLC → MFR Jul 23, 18:50 UTCJul 23, 19:40 UTC50m
2026-07-23 SKW4114 ALB → DTW Jul 23, 16:00 UTCJul 23, 17:50 UTC1h 50m
2026-07-23 SKW3708 SEA → SFO Jul 23, 13:10 UTCJul 23, 14:35 UTC1h 25m
2026-07-23 SKW137C MDT → DTW Jul 23, 05:05 UTCJul 23, 06:40 UTC1h 35m
2026-07-23 SKW3828 SLC → BIL Jul 23, 01:30 UTCJul 23, 02:25 UTC55m
2026-07-23 SKW3828 SLC → BIL Jul 23, 00:10 UTCJul 23, 00:25 UTC15m
2026-07-22 SKW3828 SLC → BIL Jul 22, 23:20 UTCJul 22, 23:35 UTC15m
2026-07-22 SKW3841 SBA → SLC Jul 22, 19:55 UTCJul 22, 21:45 UTC1h 50m
2026-07-22 SKW3841 - Jul 22, 17:00 UTCJul 22, 18:40 UTC1h 40m
2026-07-22 SKW3745 TUS → SLC Jul 22, 14:10 UTCJul 22, 15:40 UTC1h 30m
2026-07-22 SKW4054 SLC → OAK Jul 22, 03:35 UTCJul 22, 05:05 UTC1h 30m
2026-07-21 SKW3896 OMA → SLC Jul 21, 23:00 UTCJul 22, 01:15 UTC2h 15m
2026-07-21 SKW3896 OMA → SLC Jul 21, 19:45 UTCJul 21, 21:40 UTC1h 55m
2026-07-21 SKW4444 GEG → SLC Jul 21, 17:00 UTCJul 21, 18:25 UTC1h 25m
2026-07-21 SKW4444 SLC → GEG Jul 21, 14:35 UTCJul 21, 15:55 UTC1h 20m
2026-07-21 SKW4009 - Jul 21, 01:55 UTCJul 21, 03:45 UTC1h 50m
2026-07-20 SKW3585 JFK → ORD Jul 20, 22:25 UTCJul 21, 00:25 UTC2h 0m
2026-07-20 SKW3804 ROC → DTW Jul 20, 19:50 UTCJul 20, 21:20 UTC1h 30m
2026-07-20 SKW3804 ROC → DTW Jul 20, 17:05 UTCJul 20, 18:10 UTC1h 5m
2026-07-20 SKW4610 EUG → SLC Jul 20, 13:45 UTCJul 20, 15:10 UTC1h 25m
2026-07-19 SKW137C - Jul 19, 03:00 UTCJul 19, 03:15 UTC15m
2026-07-19 SKW137C SLC → EUG Jul 19, 02:59 UTCJul 19, 04:25 UTC1h 26m
2026-07-19 SKW3798 - Jul 19, 00:25 UTCJul 19, 01:40 UTC1h 15m
2026-07-18 SKW3798 - Jul 18, 21:45 UTCJul 18, 22:55 UTC1h 10m
2026-07-18 SKW4112 SLC → SLC Jul 18, 17:10 UTCJul 18, 20:40 UTC3h 30m
2026-07-18 SKW3874 OMA → SLC Jul 18, 13:20 UTCJul 18, 15:20 UTC2h 0m
2026-07-18 SKW3874 OMA → SLC Jul 18, 13:25 UTCJul 18, 15:15 UTC1h 50m
2026-07-18 SKW3706 - Jul 18, 03:25 UTCJul 18, 05:20 UTC1h 55m

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 N313SY page for operator, model, and routing details .

Mode-S A3539D frequently asked

What is Mode-S code A3539D?
A3539D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N313SY.
Where is Mode-S A3539D registered?
Mode-S code A3539D 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 A3539D broadcasting right now?
Yes. Mode-S A3539D is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A3539D, octal 50651635, decimal 10,703,773.
What flights does A3539D operate?
Mode-S A3539D has broadcast 20 distinct callsigns, including SKW4101, SKW3876, SKW3620, SKW3577, SKW4091.