Apparatus

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sensors Mode-S transponder

AAF253

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N804SK · BOMBARDIER Regional Jet CRJ-900 · operated by SKYWEST AIRLINES INC

Hex
AAF253
Octal
52571123
Decimal
11,203,155
Country
US
Tail
N804SK
Type
CRJ9
No current signal · last broadcast Jul 26, 22:10 UTC
Flights observed
589
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:10 UTC

Last known position

Most recent position reported by Mode-S AAF253.

Country allocation

The ICAO 24-bit address AAF253 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
SKW3538 - 12 2026-07-15
SKW4456 SkyWest Airlines 10 2026-06-16
SKW3868 SkyWest Airlines 10 2026-07-20
SKW3843 - 10 2026-07-20
SKW4140 SkyWest Airlines 9 2026-07-20
SKW4130 - 9 2026-07-12
SKW4089 SkyWest Airlines 9 2026-07-26
SKW3978 SkyWest Airlines 9 2026-06-09
SKW3941 SkyWest Airlines 9 2026-06-01
SKW3831 - 9 2026-07-19
SKW4144 SkyWest Airlines 8 2026-07-22
SKW4136 SkyWest Airlines 8 2026-06-24
SKW4080 SkyWest Airlines 8 2026-07-22
SKW4073 SkyWest Airlines 8 2026-07-21
SKW4032 - 8 2026-07-11
SKW3829 SkyWest Airlines 8 2026-07-22
SKW3719 SkyWest Airlines 8 2026-06-03
SKW125R SkyWest Airlines 8 2026-07-21
SKW4044 SkyWest Airlines 7 2026-05-26
SKW4003 - 7 2026-07-20

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW3935 LAX → SJC Jul 26, 21:20 UTCJul 26, 22:10 UTC50m
2026-07-26 SKW4089 SFO → SEA Jul 26, 18:25 UTCJul 26, 20:00 UTC1h 35m
2026-07-26 SKW4089 SFO → SEA Jul 26, 14:35 UTCJul 26, 16:20 UTC1h 45m
2026-07-26 SKW4460 MKE → MSP Jul 26, 12:05 UTCJul 26, 12:45 UTC40m
2026-07-26 SKW4460 MKE → MSP Jul 26, 11:59 UTCJul 26, 12:47 UTC48m
2026-07-26 SKW3724 STL → LGA Jul 26, 00:30 UTCJul 26, 01:10 UTC40m
2026-07-25 SKW3760 MSN → MSP Jul 25, 20:25 UTCJul 25, 20:50 UTC25m
2026-07-25 SKW3760 MSN → MSP Jul 25, 20:26 UTCJul 25, 20:43 UTC17m
2026-07-25 SKW3760 MSN → MSP Jul 25, 18:55 UTCJul 25, 19:25 UTC30m
2026-07-25 SKW3636 CLE → BOS Jul 25, 16:45 UTCJul 25, 17:25 UTC40m
2026-07-25 SKW3636 CLE → BOS Jul 25, 16:49 UTCJul 25, 17:22 UTC33m
2026-07-25 SKW3636 CLE → BOS Jul 25, 15:00 UTCJul 25, 15:40 UTC40m
2026-07-25 SKW3757 SLC → ONT Jul 25, 13:05 UTCJul 25, 13:40 UTC35m
2026-07-24 SKW4464 MSP → SDF Jul 24, 23:40 UTCJul 25, 00:25 UTC45m
2026-07-24 SKW4464 MSP → SDF Jul 24, 23:35 UTCJul 25, 00:25 UTC50m
2026-07-24 SKW4295 MQT → DTW Jul 24, 21:45 UTCJul 24, 22:35 UTC50m
2026-07-24 SKW4295 MQT → DTW Jul 24, 21:43 UTCJul 24, 22:31 UTC48m
2026-07-24 SKW4314 MSP → MQT Jul 24, 19:50 UTCJul 24, 20:15 UTC25m
2026-07-24 SKW3922 SJC → SLC Jul 24, 15:05 UTCJul 24, 15:35 UTC30m
2026-07-23 SKW3912 ATL → MDT Jul 23, 23:30 UTCJul 23, 23:50 UTC20m
2026-07-23 SKW3967 SAN → LAS Jul 23, 20:55 UTCJul 23, 21:50 UTC55m
2026-07-23 SKW3967 SAN → LAS Jul 23, 18:10 UTCJul 23, 19:20 UTC1h 10m
2026-07-23 SKW4466 - Jul 23, 14:50 UTCJul 23, 15:50 UTC1h 0m
2026-07-23 SKW4466 MSP → MKE Jul 23, 13:10 UTCJul 23, 13:55 UTC45m
2026-07-23 SKW4158 - Jul 23, 10:25 UTCJul 23, 11:20 UTC55m
2026-07-23 SKW4158 MOT → MSP Jul 23, 10:19 UTCJul 23, 11:15 UTC56m
2026-07-23 SKW4154 MSP → CMH Jul 23, 03:05 UTCJul 23, 04:05 UTC1h 0m
2026-07-22 SKW3829 DTW → CLE Jul 22, 23:50 UTCJul 23, 01:35 UTC1h 45m
2026-07-22 SKW4080 DTW → MDW Jul 22, 20:40 UTCJul 22, 22:05 UTC1h 25m
2026-07-22 SKW4144 BOS → JFK Jul 22, 18:05 UTCJul 22, 19:00 UTC55m
2026-07-22 SKW4144 BOS → JFK Jul 22, 15:20 UTCJul 22, 16:20 UTC1h 0m
2026-07-22 SKW3512 BOS → MKE Jul 22, 13:35 UTCJul 22, 14:20 UTC45m
2026-07-22 SKW3512 BOS → MKE Jul 22, 13:24 UTCJul 22, 14:18 UTC54m
2026-07-22 SKW4014 MSP → OMA Jul 22, 03:25 UTCJul 22, 04:10 UTC45m
2026-07-21 SKW3709 JFK → BNA Jul 21, 23:50 UTCJul 22, 02:00 UTC2h 10m
2026-07-21 SKW3709 JFK → BNA Jul 21, 21:05 UTCJul 21, 22:30 UTC1h 25m
2026-07-21 SKW4089 SFO → SEA Jul 21, 17:20 UTCJul 21, 19:05 UTC1h 45m
2026-07-21 SKW4089 SFO → SEA Jul 21, 14:35 UTCJul 21, 16:15 UTC1h 40m
2026-07-21 SKW4073 DTW → HPN Jul 21, 11:19 UTCJul 21, 13:03 UTC1h 44m
2026-07-21 SKW4073 DTW → HPN Jul 21, 11:25 UTCJul 21, 13:05 UTC1h 40m
2026-07-21 SKW125R SLC → YVR Jul 21, 01:33 UTCJul 21, 02:44 UTC1h 11m
2026-07-21 SKW125R SLC → YVR Jul 21, 01:20 UTCJul 21, 02:45 UTC1h 25m
2026-07-20 SKW3843 GRB → MSP Jul 20, 21:35 UTCJul 20, 22:25 UTC50m
2026-07-20 SKW3843 MSP → GRB Jul 20, 19:50 UTCJul 20, 20:30 UTC40m
2026-07-20 SKW149R YYZ → MSP Jul 20, 16:45 UTCJul 20, 18:30 UTC1h 45m
2026-07-20 SKW3868 MSP → IAD Jul 20, 13:50 UTCJul 20, 15:20 UTC1h 30m
2026-07-20 SKW4140 DTW → YYZ Jul 20, 11:10 UTCJul 20, 12:10 UTC1h 0m
2026-07-20 SKW4003 - Jul 20, 01:50 UTCJul 20, 02:30 UTC40m
2026-07-19 SKW3865 - Jul 19, 20:20 UTCJul 19, 21:30 UTC1h 10m
2026-07-19 SKW3865 MSP → GRR Jul 19, 18:20 UTCJul 19, 19:15 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 N804SK page for operator, model, and routing details .

Mode-S AAF253 frequently asked

What is Mode-S code AAF253?
AAF253 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N804SK.
Where is Mode-S AAF253 registered?
Mode-S code AAF253 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 AAF253 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:10 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AAF253, octal 52571123, decimal 11,203,155.
What flights does AAF253 operate?
Mode-S AAF253 has broadcast 20 distinct callsigns, including SKW3538, SKW4456, SKW3868, SKW3843, SKW4140.