Apparatus

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sensors Mode-S transponder

A1A9F4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N206SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A1A9F4
Octal
50324764
Decimal
10,594,804
Country
US
Tail
N206SY
Type
E75L
No current signal · last broadcast Jul 26, 21:00 UTC
Flights observed
637
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:00 UTC

Last known position

Most recent position reported by Mode-S A1A9F4.

Country allocation

The ICAO 24-bit address A1A9F4 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
SKW5586 SkyWest Airlines 7 2026-06-25
SKW5453 SkyWest Airlines 7 2026-07-24
SKW5278 SkyWest Airlines 7 2026-07-24
SKW5222 - 7 2026-07-19
SKW5938 - 6 2026-07-13
SKW5672 SkyWest Airlines 6 2026-07-24
SKW5429 - 6 2026-07-19
SKW5414 SkyWest Airlines 6 2026-07-23
SKW5247 SkyWest Airlines 6 2026-07-22
SKW5223 - 6 2026-07-19
SKW4732 SkyWest Airlines 6 2026-07-24
SKW5798 SkyWest Airlines 5 2026-07-23
SKW5545 - 5 2026-07-04
SKW5505 SkyWest Airlines 5 2026-05-11
SKW5483 - 5 2026-07-17
SKW5368 SkyWest Airlines 5 2026-04-29
SKW4809 SkyWest Airlines 5 2026-06-19
SKW4749 - 5 2026-07-02
SKW4707 SkyWest Airlines 5 2026-05-29
SKW4667 - 5 2026-07-16

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW4699 BZN → SFO Jul 26, 20:10 UTCJul 26, 21:00 UTC50m
2026-07-26 SKW5932 SFO → PSC Jul 26, 17:35 UTCJul 26, 19:00 UTC1h 25m
2026-07-26 SKW5932 SFO → PSC Jul 26, 17:41 UTCJul 26, 19:02 UTC1h 21m
2026-07-26 SKW4664 SFO → ABQ Jul 26, 12:55 UTCJul 26, 15:05 UTC2h 10m
2026-07-26 SKW4664 SFO → ABQ Jul 26, 13:04 UTCJul 26, 14:49 UTC1h 45m
2026-07-25 SKW4791 SFO → RDD Jul 25, 20:35 UTCJul 25, 22:20 UTC1h 45m
2026-07-25 SKW5659 LAS → SFO Jul 25, 14:30 UTCJul 25, 17:10 UTC2h 40m
2026-07-25 SKW5533 SFO → RDD Jul 25, 01:25 UTCJul 25, 04:00 UTC2h 35m
2026-07-24 SKW4732 ASE → IAH Jul 24, 21:20 UTCJul 24, 23:50 UTC2h 30m
2026-07-24 SKW4732 ASE → IAH Jul 24, 21:23 UTCJul 24, 23:31 UTC2h 8m
2026-07-24 SKW5424 DEN → TUS Jul 24, 17:40 UTCJul 24, 19:45 UTC2h 5m
2026-07-24 SKW5672 SFO → ONT Jul 24, 15:05 UTCJul 24, 16:35 UTC1h 30m
2026-07-24 SKW5672 SFO → ONT Jul 24, 15:06 UTCJul 24, 16:21 UTC1h 15m
2026-07-24 SKW5360 LGA → IAH Jul 24, 12:35 UTCJul 24, 13:45 UTC1h 10m
2026-07-24 SKW5453 SFO → SAT Jul 24, 10:20 UTCJul 24, 11:25 UTC1h 5m
2026-07-24 SKW5278 HPN → ORD Jul 24, 00:35 UTCJul 24, 01:40 UTC1h 5m
2026-07-23 SKW5798 SBA → SFO Jul 23, 20:50 UTCJul 23, 22:05 UTC1h 15m
2026-07-23 SKW5414 FAR → DEN Jul 23, 18:25 UTCJul 23, 19:35 UTC1h 10m
2026-07-23 SKW5414 FAR → DEN Jul 23, 18:11 UTCJul 23, 19:37 UTC1h 26m
2026-07-23 SKW5717 ABE → ORD Jul 23, 15:00 UTCJul 23, 16:30 UTC1h 30m
2026-07-23 SKW5717 ABE → ORD Jul 23, 15:06 UTCJul 23, 16:11 UTC1h 5m
2026-07-23 SKW5325 SNA → SFO Jul 23, 12:50 UTCJul 23, 13:55 UTC1h 5m
2026-07-22 SKW5478 ORD → GSP Jul 22, 22:30 UTCJul 22, 23:30 UTC1h 0m
2026-07-22 SKW5760 DEN → LIT Jul 22, 19:40 UTCJul 22, 21:00 UTC1h 20m
2026-07-22 SKW5760 DEN → LIT Jul 22, 19:40 UTCJul 22, 21:13 UTC1h 33m
2026-07-22 SKW5358 BOI → SFO Jul 22, 16:40 UTCJul 22, 18:00 UTC1h 20m
2026-07-22 SKW5247 ORD → AVP Jul 22, 14:20 UTCJul 22, 15:44 UTC1h 24m
2026-07-22 SKW5247 ORD → AVP Jul 22, 14:20 UTCJul 22, 15:45 UTC1h 25m
2026-07-22 SKW5667 ORD → MSN Jul 22, 11:20 UTCJul 22, 12:40 UTC1h 20m
2026-07-22 SKW5667 ORD → MSN Jul 22, 11:16 UTCJul 22, 12:34 UTC1h 18m
2026-07-22 SKW4712 ORD → CHA Jul 22, 03:05 UTCJul 22, 04:20 UTC1h 15m
2026-07-22 SKW4758 SFO → SNA Jul 22, 00:15 UTCJul 22, 01:35 UTC1h 20m
2026-07-21 SKW5498 LEX → ORD Jul 21, 21:50 UTCJul 21, 23:00 UTC1h 10m
2026-07-21 SKW5498 LEX → ORD Jul 21, 21:57 UTCJul 21, 22:55 UTC58m
2026-07-21 SKW5812 - Jul 21, 18:40 UTCJul 21, 20:05 UTC1h 25m
2026-07-21 SKW5267 DEN → XNA Jul 21, 16:05 UTCJul 21, 17:30 UTC1h 25m
2026-07-21 SKW4705 DEN → HLN Jul 21, 01:55 UTCJul 21, 13:55 UTC12h 0m
2026-07-20 SKW4768 LGA → ORD Jul 20, 22:45 UTCJul 21, 00:00 UTC1h 14m
2026-07-20 SKW5808 DEN → OKC Jul 20, 20:00 UTCJul 20, 21:00 UTC1h 0m
2026-07-20 SKW5808 DEN → OKC Jul 20, 19:52 UTCJul 20, 21:15 UTC1h 23m
2026-07-20 SKW5490 BHM → ORD Jul 20, 16:45 UTCJul 20, 18:00 UTC1h 15m
2026-07-20 SKW6029 DEN → OKC Jul 20, 14:30 UTCJul 20, 15:45 UTC1h 15m
2026-07-20 SKW5969 SFO → SEA Jul 20, 10:55 UTCJul 20, 12:25 UTC1h 30m
2026-07-20 SKW5969 SFO → SEA Jul 20, 11:08 UTCJul 20, 12:21 UTC1h 13m
2026-07-20 SKW5269 DEN → SJC Jul 20, 03:02 UTCJul 20, 04:28 UTC1h 26m
2026-07-20 SKW5269 DEN → SJC Jul 20, 02:55 UTCJul 20, 04:30 UTC1h 35m
2026-07-19 SKW5429 - Jul 19, 22:00 UTCJul 19, 23:35 UTC1h 35m
2026-07-19 SKW5340 ORD → LGA Jul 19, 19:35 UTCJul 19, 20:15 UTC40m
2026-07-19 SKW5223 - Jul 19, 16:15 UTCJul 19, 17:20 UTC1h 5m
2026-07-19 SKW5223 MTY → IAH Jul 19, 16:12 UTCJul 19, 17:19 UTC1h 7m

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 N206SY page for operator, model, and routing details .

Mode-S A1A9F4 frequently asked

What is Mode-S code A1A9F4?
A1A9F4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N206SY.
Where is Mode-S A1A9F4 registered?
Mode-S code A1A9F4 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 A1A9F4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1A9F4, octal 50324764, decimal 10,594,804.
What flights does A1A9F4 operate?
Mode-S A1A9F4 has broadcast 20 distinct callsigns, including SKW5586, SKW5453, SKW5278, SKW5222, SKW5938.