Apparatus

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sensors Mode-S transponder

A1ECFF

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N223JS · BOMBARDIER Regional Jet CRJ-200 · operated by SKYWEST AIRLINES INC

Hex
A1ECFF
Octal
50366377
Decimal
10,611,967
Country
US
Tail
N223JS
Type
CRJ2
No current signal · last broadcast 7d ago
Flights observed
492
Distinct callsigns
20
Country
US
Last broadcast
7d ago

Last known position

Most recent position reported by Mode-S A1ECFF.

Country allocation

The ICAO 24-bit address A1ECFF 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
SKW5087 - 6 2026-06-23
SKW5064 SkyWest Airlines 6 2026-07-03
SKW5057 SkyWest Airlines 6 2026-06-13
SKW5029 - 6 2026-07-05
SKW4631 SkyWest Airlines 6 2026-06-09
SKW5952 - 5 2026-06-17
SKW5224 - 5 2026-06-17
SKW5085 - 5 2026-06-16
SKW5024 SkyWest Airlines 5 2026-05-29
SKW5023 - 5 2026-06-23
SKW4752 - 5 2026-06-29
SKW4736 SkyWest Airlines 5 2026-06-08
SKW6073 - 4 2026-06-28
SKW6067 SkyWest Airlines 4 2026-05-17
SKW6056 - 4 2026-06-22
SKW5585 SkyWest Airlines 4 2026-06-08
SKW5127 SkyWest Airlines 4 2026-05-26
SKW5120 - 4 2026-06-16
SKW5117 - 4 2026-06-11
SKW5077 - 4 2026-06-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-07 SKW5143 - Jul 7, 17:40 UTCJul 7, 17:55 UTC15m
2026-07-06 SKW4645 - Jul 6, 17:50 UTCJul 6, 18:15 UTC25m
2026-07-06 SKW5910 LNK → ORD Jul 6, 15:35 UTCJul 6, 16:21 UTC46m
2026-07-06 SKW5910 - Jul 6, 15:05 UTCJul 6, 15:15 UTC10m
2026-07-06 SKW5314 - Jul 6, 02:10 UTCJul 6, 03:20 UTC1h 10m
2026-07-05 SKW5029 - Jul 5, 22:20 UTCJul 5, 22:25 UTC5m
2026-07-05 SKW5029 - Jul 5, 20:50 UTCJul 5, 22:25 UTC1h 35m
2026-07-05 SKW5029 JST → ORD Jul 5, 20:35 UTCJul 5, 22:02 UTC1h 27m
2026-07-05 SKW576U - Jul 5, 19:15 UTCJul 5, 19:50 UTC35m
2026-07-05 SKW576U IAD → JST Jul 5, 19:08 UTCJul 5, 19:50 UTC42m
2026-07-05 SKW5025 MGW → IAD Jul 5, 17:30 UTCJul 5, 18:00 UTC30m
2026-07-05 SKW470P IAD → MGW Jul 5, 16:02 UTCJul 5, 16:27 UTC25m
2026-07-05 SKW5041 LYH → IAD Jul 5, 03:55 UTCJul 5, 04:00 UTC5m
2026-07-05 SKW5041 - Jul 5, 03:35 UTCJul 5, 04:10 UTC35m
2026-07-04 SKW5067 - Jul 4, 21:55 UTCJul 4, 23:15 UTC1h 20m
2026-07-04 SKW5029 - Jul 4, 18:35 UTCJul 4, 19:55 UTC1h 20m
2026-07-04 SKW5199 - Jul 4, 04:30 UTCJul 4, 07:10 UTC2h 40m
2026-07-03 SKW5930 ORD → FAR Jul 3, 20:10 UTCJul 3, 21:40 UTC1h 30m
2026-07-03 SKW5448 - Jul 3, 15:40 UTCJul 3, 17:15 UTC1h 35m
2026-07-03 SKW4789 ORD → FAR Jul 3, 05:50 UTCJul 3, 07:15 UTC1h 25m
2026-07-03 SKW5064 DEC → ORD Jul 3, 00:00 UTCJul 3, 00:50 UTC50m
2026-07-02 SKW5064 DEC → ORD Jul 2, 23:57 UTCJul 3, 00:28 UTC31m
2026-07-02 SKW5064 DEC → ORD Jul 2, 22:20 UTCJul 2, 22:50 UTC30m
2026-07-02 SKW6077 - Jul 2, 19:40 UTCJul 2, 20:30 UTC50m
2026-07-02 SKW546J - Jul 2, 17:50 UTCJul 2, 18:30 UTC40m
2026-07-02 SKW546J ORD → CIU Jul 2, 17:43 UTCJul 2, 18:38 UTC55m
2026-07-02 SKW4676 - Jul 2, 14:20 UTCJul 2, 15:05 UTC45m
2026-07-02 SKW5317 - Jul 2, 02:55 UTCJul 2, 03:35 UTC40m
2026-07-02 SKW4681 DEN → LEX Jul 2, 00:00 UTCJul 2, 00:40 UTC40m
2026-07-02 SKW4681 DEN → LEX Jul 2, 00:04 UTCJul 2, 00:43 UTC39m
2026-07-01 SKW5907 - Jul 1, 22:05 UTCJul 1, 22:40 UTC35m
2026-07-01 SKW4747 - Jul 1, 19:30 UTCJul 1, 19:45 UTC15m
2026-07-01 SKW4747 - Jul 1, 18:45 UTCJul 1, 19:45 UTC1h 0m
2026-07-01 SKW4747 DAY → ORD Jul 1, 18:54 UTCJul 1, 19:14 UTC20m
2026-07-01 SKW727R - Jul 1, 16:50 UTCJul 1, 17:35 UTC45m
2026-07-01 SKW727R ORD → DAY Jul 1, 17:00 UTCJul 1, 17:33 UTC33m
2026-07-01 SKW5016 CMX → ORD Jul 1, 13:32 UTCJul 1, 14:36 UTC1h 4m
2026-07-01 SKW404X - Jul 1, 03:40 UTCJul 1, 04:25 UTC45m
2026-07-01 SKW404X ORD → CMX Jul 1, 03:40 UTCJul 1, 04:34 UTC54m
2026-07-01 SKW5653 - Jul 1, 01:25 UTCJul 1, 01:45 UTC20m
2026-07-01 SKW5653 - Jul 1, 01:00 UTCJul 1, 01:45 UTC45m
2026-07-01 SKW5653 MKE → ORD Jul 1, 01:05 UTCJul 1, 01:10 UTC5m
2026-06-30 SKW5555 - Jun 30, 23:50 UTCJul 1, 00:05 UTC15m
2026-06-30 SKW4726 - Jun 30, 20:25 UTCJun 30, 20:50 UTC25m
2026-06-30 SKW4726 MKE → ORD Jun 30, 20:23 UTCJun 30, 20:41 UTC18m
2026-06-30 SKW5933 - Jun 30, 18:45 UTCJun 30, 19:05 UTC20m
2026-06-30 SKW5448 - Jun 30, 15:05 UTCJun 30, 16:35 UTC1h 30m
2026-06-30 SKW4789 ORD → FAR Jun 30, 03:00 UTCJun 30, 04:40 UTC1h 40m
2026-06-30 SKW5064 DEC → ORD Jun 30, 00:01 UTCJun 30, 00:16 UTC15m
2026-06-29 SKW5064 DEC → ORD Jun 29, 23:49 UTCJun 30, 00:30 UTC40m

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 N223JS page for operator, model, and routing details .

Mode-S A1ECFF frequently asked

What is Mode-S code A1ECFF?
A1ECFF is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N223JS.
Where is Mode-S A1ECFF registered?
Mode-S code A1ECFF 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 A1ECFF broadcasting right now?
No active broadcast right now. Last signal was 7d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1ECFF, octal 50366377, decimal 10,611,967.
What flights does A1ECFF operate?
Mode-S A1ECFF has broadcast 20 distinct callsigns, including SKW5087, SKW5064, SKW5057, SKW5029, SKW4631.