Apparatus

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sensors Mode-S transponder

AC685D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N899SK · BOMBARDIER Regional Jet CRJ-900 · operated by SKYWEST AIRLINES INC

Hex
AC685D
Octal
53064135
Decimal
11,298,909
Country
US
Tail
N899SK
Type
CRJ9
No current signal · last broadcast Jul 26, 19:00 UTC
Flights observed
374
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 19:00 UTC

Last known position

Most recent position reported by Mode-S AC685D.

Country allocation

The ICAO 24-bit address AC685D 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
SKW4065 SkyWest Airlines 14 2026-06-15
SKW3783 - 11 2026-07-13
SKW4130 SkyWest Airlines 10 2026-07-18
SKW4089 - 10 2026-07-09
SKW3967 SkyWest Airlines 10 2026-07-22
SKW4102 SkyWest Airlines 9 2026-07-20
SKW3642 SkyWest Airlines 9 2026-07-23
SKW4144 SkyWest Airlines 8 2026-07-19
SKW3888 - 8 2026-06-27
SKW3636 SkyWest Airlines 8 2026-07-23
SKW4080 SkyWest Airlines 7 2026-07-21
SKW4066 - 7 2026-06-26
SKW3861 - 7 2026-07-16
SKW3714 - 7 2026-07-14
SKW3538 - 7 2026-07-20
SKW3927 - 6 2026-07-14
SKW3829 SkyWest Airlines 6 2026-07-22
SKW3761 - 6 2026-06-14
SKW3646 SkyWest Airlines 6 2026-07-24
SKW3637 SkyWest Airlines 6 2026-07-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW4055 SJC → SEA Jul 26, 17:30 UTCJul 26, 19:00 UTC1h 30m
2026-07-26 SKW3962 BOS → PIT Jul 26, 15:10 UTCJul 26, 15:35 UTC25m
2026-07-26 SKW4173 MSN → MSP Jul 26, 01:55 UTCJul 26, 02:20 UTC25m
2026-07-25 SKW4166 ATW → DTW Jul 25, 22:50 UTCJul 25, 23:30 UTC40m
2026-07-25 SKW4166 ATW → DTW Jul 25, 22:56 UTCJul 25, 23:29 UTC33m
2026-07-25 SKW4166 ATW → DTW Jul 25, 20:40 UTCJul 25, 21:30 UTC50m
2026-07-25 SKW3976 SDF → MSP Jul 25, 18:55 UTCJul 25, 19:30 UTC35m
2026-07-25 SKW3976 SDF → MSP Jul 25, 17:15 UTCJul 25, 17:40 UTC25m
2026-07-25 SKW3843 HPN → DTW Jul 25, 14:45 UTCJul 25, 15:25 UTC40m
2026-07-25 SKW3843 HPN → DTW Jul 25, 12:45 UTCJul 25, 13:25 UTC40m
2026-07-25 SKW3858 DTW → OMA Jul 25, 10:25 UTCJul 25, 11:20 UTC55m
2026-07-25 SKW3949 LGA → BNA Jul 25, 01:55 UTCJul 25, 02:35 UTC40m
2026-07-24 SKW4007 PIT → JFK Jul 24, 23:00 UTCJul 25, 00:25 UTC1h 25m
2026-07-24 SKW4007 PIT → JFK Jul 24, 20:25 UTCJul 24, 21:45 UTC1h 20m
2026-07-24 SKW3559 PIT → MSP Jul 24, 18:45 UTCJul 24, 19:10 UTC25m
2026-07-24 SKW3559 PIT → MSP Jul 24, 17:20 UTCJul 24, 17:40 UTC20m
2026-07-24 SKW3500 LAX → SFO Jul 24, 15:40 UTCJul 24, 16:10 UTC30m
2026-07-24 SKW3500 LAX → SFO Jul 24, 14:10 UTCJul 24, 14:30 UTC20m
2026-07-24 SKW3817 MOT → MSP Jul 24, 12:20 UTCJul 24, 12:45 UTC25m
2026-07-24 SKW3646 RDM → SEA Jul 24, 03:15 UTCJul 24, 03:40 UTC25m
2026-07-24 SKW3637 LAX → SMF Jul 24, 00:00 UTCJul 24, 00:40 UTC40m
2026-07-23 SKW3637 LAX → SMF Jul 23, 22:10 UTCJul 23, 22:55 UTC45m
2026-07-23 SKW3642 DTW → CMH Jul 23, 20:10 UTCJul 23, 20:50 UTC40m
2026-07-23 SKW3642 DTW → CMH Jul 23, 20:11 UTCJul 23, 20:48 UTC37m
2026-07-23 SKW3642 DTW → CMH Jul 23, 18:15 UTCJul 23, 18:55 UTC40m
2026-07-23 SKW3636 CLE → BOS Jul 23, 16:10 UTCJul 23, 16:55 UTC45m
2026-07-23 SKW3636 CLE → BOS Jul 23, 14:30 UTCJul 23, 15:15 UTC45m
2026-07-23 SKW3757 SLC → ONT Jul 23, 12:35 UTCJul 23, 13:20 UTC45m
2026-07-22 SKW4464 MSP → MKE Jul 22, 23:30 UTCJul 23, 00:20 UTC50m
2026-07-22 SKW3967 SAN → LAS Jul 22, 21:00 UTCJul 22, 22:00 UTC1h 0m
2026-07-22 SKW3967 SAN → LAS Jul 22, 18:10 UTCJul 22, 19:15 UTC1h 5m
2026-07-22 SKW4466 - Jul 22, 14:55 UTCJul 22, 15:45 UTC50m
2026-07-22 SKW4466 MSP → MKE Jul 22, 12:50 UTCJul 22, 13:35 UTC45m
2026-07-22 SKW3829 DTW → CLE Jul 22, 01:00 UTCJul 22, 02:45 UTC1h 45m
2026-07-21 SKW4080 DTW → MDW Jul 21, 22:37 UTCJul 21, 23:49 UTC1h 12m
2026-07-21 SKW4080 DTW → MDW Jul 21, 22:25 UTCJul 21, 23:55 UTC1h 30m
2026-07-21 SKW3534 ORD → BOS Jul 21, 18:40 UTCJul 21, 19:15 UTC35m
2026-07-21 SKW3534 ORD → BOS Jul 21, 16:55 UTCJul 21, 17:30 UTC35m
2026-07-21 SKW4103 OAK → SLC Jul 21, 14:00 UTCJul 21, 14:40 UTC40m
2026-07-21 SKW4103 OAK → SLC Jul 21, 12:15 UTCJul 21, 12:55 UTC40m
2026-07-21 SKW3840 SEA → SJC Jul 21, 10:15 UTCJul 21, 10:50 UTC35m
2026-07-20 SKW3578 LWS → SLC Jul 20, 23:55 UTCJul 21, 00:30 UTC35m
2026-07-20 SKW3538 FSD → MSP Jul 20, 21:40 UTCJul 20, 22:20 UTC40m
2026-07-20 SKW3538 FSD → MSP Jul 20, 21:46 UTCJul 20, 22:15 UTC29m
2026-07-20 SKW3538 MSP → FSD Jul 20, 20:00 UTCJul 20, 20:40 UTC40m
2026-07-20 SKW4102 MKE → LGA Jul 20, 17:20 UTCJul 20, 18:10 UTC50m
2026-07-20 SKW4102 MKE → LGA Jul 20, 15:30 UTCJul 20, 16:10 UTC40m
2026-07-20 SKW3922 - Jul 20, 13:15 UTCJul 20, 13:45 UTC30m
2026-07-19 SKW3912 - Jul 19, 23:55 UTCJul 20, 00:15 UTC20m
2026-07-19 SKW3843 - Jul 19, 21:25 UTCJul 19, 22:10 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 N899SK page for operator, model, and routing details .

Mode-S AC685D frequently asked

What is Mode-S code AC685D?
AC685D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N899SK.
Where is Mode-S AC685D registered?
Mode-S code AC685D 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 AC685D broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 19:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AC685D, octal 53064135, decimal 11,298,909.
What flights does AC685D operate?
Mode-S AC685D has broadcast 20 distinct callsigns, including SKW4065, SKW3783, SKW4130, SKW4089, SKW3967.