Apparatus

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sensors Mode-S transponder

AB8173

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N840SK · BOMBARDIER Regional Jet CRJ-900 · operated by DELTA AIR LINES INC

Hex
AB8173
Octal
52700563
Decimal
11,239,795
Country
US
Tail
N840SK
Type
CRJ9
No current signal · last broadcast Jul 26, 21:40 UTC
Flights observed
838
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:40 UTC

Last known position

Most recent position reported by Mode-S AB8173.

Country allocation

The ICAO 24-bit address AB8173 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
SKW4034 - 37 2026-07-19
SKW3500 - 20 2026-07-23
SKW3752 SkyWest Airlines 19 2026-07-21
SKW4059 SkyWest Airlines 17 2026-07-25
SKW4021 - 17 2026-06-29
SKW3949 SkyWest Airlines 14 2026-07-23
SKW3919 SkyWest Airlines 14 2026-07-25
SKW3889 - 14 2026-07-14
SKW3565 SkyWest Airlines 14 2026-07-24
SKW4173 SkyWest Airlines 13 2026-07-21
SKW3898 - 13 2026-07-07
SKW3878 SkyWest Airlines 13 2026-05-29
SKW3559 - 13 2026-07-20
SKW3533 SkyWest Airlines 13 2026-07-22
SKW4166 - 12 2026-07-12
SKW3962 - 12 2026-07-21
SKW3784 SkyWest Airlines 12 2026-05-20
SKW3782 SkyWest Airlines 12 2026-07-19
SKW3993 SkyWest Airlines 11 2026-06-03
SKW3961 - 11 2026-07-15

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW3642 DTW → CMH Jul 26, 20:50 UTCJul 26, 21:40 UTC50m
2026-07-26 SKW3642 DTW → CMH Jul 26, 19:05 UTCJul 26, 19:45 UTC40m
2026-07-26 SKW4065 SEA → PDX Jul 26, 16:45 UTCJul 26, 17:50 UTC1h 5m
2026-07-26 SKW4065 SEA → PDX Jul 26, 14:45 UTCJul 26, 15:35 UTC50m
2026-07-26 SKW3639 FWA → MSP Jul 26, 13:05 UTCJul 26, 13:50 UTC45m
2026-07-26 SKW3639 FWA → MSP Jul 26, 11:15 UTCJul 26, 11:55 UTC40m
2026-07-25 SKW3558 MSP → MSN Jul 25, 21:05 UTCJul 25, 22:25 UTC1h 20m
2026-07-25 SKW3558 MSP → MSN Jul 25, 18:40 UTCJul 25, 19:50 UTC1h 10m
2026-07-25 SKW4059 DTW → HPN Jul 25, 16:50 UTCJul 25, 17:30 UTC40m
2026-07-25 SKW4059 DTW → HPN Jul 25, 14:55 UTCJul 25, 15:45 UTC50m
2026-07-25 SKW3639 FWA → MSP Jul 25, 13:00 UTCJul 25, 13:40 UTC40m
2026-07-25 SKW3639 FWA → MSP Jul 25, 11:10 UTCJul 25, 11:55 UTC45m
2026-07-25 SKW3919 MDW → MSP Jul 25, 00:50 UTCJul 25, 01:15 UTC25m
2026-07-25 SKW3919 MDW → MSP Jul 25, 00:51 UTCJul 25, 01:07 UTC16m
2026-07-24 SKW3919 MDW → MSP Jul 24, 23:40 UTCJul 25, 00:05 UTC25m
2026-07-24 SKW3565 DTW → ORF Jul 24, 21:20 UTCJul 24, 22:20 UTC1h 0m
2026-07-24 SKW3565 DTW → ORF Jul 24, 19:15 UTCJul 24, 20:05 UTC50m
2026-07-24 SKW3869 DTW → MDW Jul 24, 17:15 UTCJul 24, 18:20 UTC1h 5m
2026-07-24 SKW3869 DTW → MDW Jul 24, 15:10 UTCJul 24, 15:55 UTC45m
2026-07-24 SKW3639 FWA → MSP Jul 24, 13:10 UTCJul 24, 13:50 UTC40m
2026-07-24 SKW3639 FWA → MSP Jul 24, 11:25 UTCJul 24, 12:05 UTC40m
2026-07-24 SKW4060 MSP → GFK Jul 24, 09:35 UTCJul 24, 09:55 UTC20m
2026-07-24 SKW3684 SLC → PSC Jul 24, 03:25 UTCJul 24, 03:40 UTC15m
2026-07-24 SKW3598 LAX → SJC Jul 24, 00:05 UTCJul 24, 00:45 UTC40m
2026-07-23 SKW3598 LAX → SJC Jul 23, 22:00 UTCJul 23, 22:40 UTC40m
2026-07-23 SKW3762 - Jul 23, 19:20 UTCJul 23, 20:50 UTC1h 30m
2026-07-23 SKW3762 OMA → DTW Jul 23, 19:20 UTCJul 23, 20:45 UTC1h 25m
2026-07-23 SKW3762 - Jul 23, 16:45 UTCJul 23, 18:20 UTC1h 35m
2026-07-23 SKW3500 - Jul 23, 14:40 UTCJul 23, 15:10 UTC30m
2026-07-23 SKW3500 DTW → GRR Jul 23, 13:00 UTCJul 23, 13:25 UTC25m
2026-07-23 SKW3858 DTW → OMA Jul 23, 10:15 UTCJul 23, 11:10 UTC55m
2026-07-23 SKW3949 LGA → BNA Jul 23, 02:05 UTCJul 23, 02:50 UTC45m
2026-07-22 SKW4007 PIT → JFK Jul 22, 23:30 UTCJul 23, 00:50 UTC1h 20m
2026-07-22 SKW4007 PIT → JFK Jul 22, 21:05 UTCJul 22, 22:25 UTC1h 20m
2026-07-22 SKW3533 SLC → SJC Jul 22, 18:10 UTCJul 22, 19:10 UTC1h 0m
2026-07-22 SKW3533 SLC → SJC Jul 22, 16:20 UTCJul 22, 17:05 UTC45m
2026-07-22 SKW3500 - Jul 22, 14:45 UTCJul 22, 15:10 UTC25m
2026-07-22 SKW3500 - Jul 22, 13:15 UTCJul 22, 13:40 UTC25m
2026-07-21 SKW4007 PIT → JFK Jul 21, 22:45 UTCJul 22, 00:10 UTC1h 25m
2026-07-21 SKW4007 PIT → JFK Jul 21, 20:10 UTCJul 21, 21:45 UTC1h 35m
2026-07-21 SKW3752 AUS → CVG Jul 21, 18:25 UTCJul 21, 18:55 UTC30m
2026-07-21 SKW3752 AUS → CVG Jul 21, 16:55 UTCJul 21, 17:15 UTC20m
2026-07-21 SKW3500 - Jul 21, 14:50 UTCJul 21, 15:20 UTC30m
2026-07-21 SKW3500 GRR → DTW Jul 21, 14:53 UTCJul 21, 15:12 UTC19m
2026-07-21 SKW3500 - Jul 21, 13:35 UTCJul 21, 14:00 UTC25m
2026-07-21 SKW3962 - Jul 21, 11:05 UTCJul 21, 11:25 UTC20m
2026-07-21 SKW4173 MSN → MSP Jul 21, 01:55 UTCJul 21, 02:20 UTC25m
2026-07-20 SKW4007 PIT → JFK Jul 20, 22:50 UTCJul 21, 00:25 UTC1h 35m
2026-07-20 SKW4007 PIT → JFK Jul 20, 20:15 UTCJul 20, 21:40 UTC1h 25m
2026-07-20 SKW3559 - Jul 20, 18:25 UTCJul 20, 18:50 UTC25m

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 N840SK page for operator, model, and routing details .

Mode-S AB8173 frequently asked

What is Mode-S code AB8173?
AB8173 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N840SK.
Where is Mode-S AB8173 registered?
Mode-S code AB8173 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 AB8173 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:40 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AB8173, octal 52700563, decimal 11,239,795.
What flights does AB8173 operate?
Mode-S AB8173 has broadcast 20 distinct callsigns, including SKW4034, SKW3500, SKW3752, SKW4059, SKW4021.