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sensors Mode-S transponder

A1099F

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N166SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A1099F
Octal
50204637
Decimal
10,553,759
Country
US
Tail
N166SY
Type
E75L
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
637
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A1099F.

Country allocation

The ICAO 24-bit address A1099F 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
SKW5623 - 9 2026-07-05
SKW6014 - 6 2026-07-04
SKW5429 - 6 2026-07-20
SKW6001 SkyWest Airlines 5 2026-05-24
SKW5938 SkyWest Airlines 5 2026-05-30
SKW5932 - 5 2026-07-07
SKW5795 - 5 2026-06-30
SKW5756 SkyWest Airlines 5 2026-05-21
SKW5672 SkyWest Airlines 5 2026-05-16
SKW5593 - 5 2026-07-17
SKW5473 SkyWest Airlines 5 2026-07-26
SKW5451 SkyWest Airlines 5 2026-07-25
SKW5340 SkyWest Airlines 5 2026-07-20
SKW5875 - 4 2026-07-14
SKW5760 SkyWest Airlines 4 2026-05-15
SKW5683 - 4 2026-07-22
SKW5654 SkyWest Airlines 4 2026-07-26
SKW5645 SkyWest Airlines 4 2026-06-14
SKW5586 SkyWest Airlines 4 2026-06-20
SKW5567 SkyWest Airlines 4 2026-06-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW5654 SUN → ORD Jul 26, 19:15 UTCJul 26, 21:35 UTC2h 20m
2026-07-26 SKW5473 SNA → SFO Jul 26, 16:25 UTCJul 26, 18:15 UTC1h 50m
2026-07-26 SKW4673 FCA → DEN Jul 26, 12:25 UTCJul 26, 14:15 UTC1h 50m
2026-07-25 SKW5451 SFO → BFL Jul 25, 19:55 UTCJul 25, 21:25 UTC1h 30m
2026-07-25 SKW5434 FWA → ORD Jul 25, 15:50 UTCJul 25, 17:55 UTC2h 5m
2026-07-25 SKW4672 - Jul 25, 12:40 UTCJul 25, 14:30 UTC1h 50m
2026-07-25 SKW4672 ORD → JAX Jul 25, 12:34 UTCJul 25, 14:28 UTC1h 54m
2026-07-25 SKW6050 ORD → GEG Jul 25, 00:10 UTCJul 25, 01:15 UTC1h 5m
2026-07-24 SKW5230 SFO → PSC Jul 24, 22:59 UTCJul 24, 23:22 UTC23m
2026-07-24 SKW5230 SFO → PSC Jul 24, 22:35 UTCJul 24, 23:25 UTC50m
2026-07-24 SKW4795 BUR → SFO Jul 24, 19:30 UTCJul 24, 21:00 UTC1h 30m
2026-07-24 SKW5413 DEN → MRY Jul 24, 17:15 UTCJul 24, 18:20 UTC1h 5m
2026-07-24 SKW5284 SFO → ONT Jul 24, 13:35 UTCJul 24, 14:55 UTC1h 20m
2026-07-24 SKW5284 SFO → ONT Jul 24, 13:25 UTCJul 24, 14:51 UTC1h 26m
2026-07-24 SKW5283 IAH → SLP Jul 24, 00:00 UTCJul 24, 01:29 UTC1h 29m
2026-07-23 SKW5837 SHV → IAH Jul 23, 20:50 UTCJul 23, 21:35 UTC45m
2026-07-23 SKW5253 LAX → SFO Jul 23, 17:20 UTCJul 23, 19:05 UTC1h 45m
2026-07-23 SKW5544 TUL → ORD Jul 23, 00:00 UTCJul 23, 02:55 UTC2h 55m
2026-07-22 SKW4802 DEN → MKE Jul 22, 19:50 UTCJul 22, 21:50 UTC2h 0m
2026-07-22 SKW716R DEN → DEN Jul 22, 14:05 UTCJul 22, 18:45 UTC4h 40m
2026-07-22 SKW5683 - Jul 22, 11:30 UTCJul 22, 12:25 UTC55m
2026-07-21 SKW5261 ORD → SDF Jul 21, 22:47 UTCJul 21, 23:46 UTC59m
2026-07-21 SKW5261 ORD → SDF Jul 21, 22:45 UTCJul 21, 23:50 UTC1h 5m
2026-07-21 SKW5492 FSD → DEN Jul 21, 18:40 UTCJul 21, 19:55 UTC1h 15m
2026-07-21 SKW4759 DEN → FSD Jul 21, 16:34 UTCJul 21, 17:35 UTC1h 1m
2026-07-21 SKW4706 IDA → DEN Jul 21, 14:15 UTCJul 21, 15:15 UTC1h 0m
2026-07-21 SKW519M DEN → IDA Jul 21, 01:45 UTCJul 21, 02:40 UTC55m
2026-07-20 SKW5429 - Jul 20, 22:10 UTCJul 21, 00:00 UTC1h 49m
2026-07-20 SKW5340 ORD → LGA Jul 20, 20:05 UTCJul 20, 21:00 UTC55m
2026-07-20 SKW5223 MTY → IAH Jul 20, 16:12 UTCJul 20, 16:58 UTC46m
2026-07-20 SKW5223 - Jul 20, 16:00 UTCJul 20, 17:00 UTC1h 0m
2026-07-20 SKW5222 IAH → MTY Jul 20, 13:20 UTCJul 20, 14:30 UTC1h 10m
2026-07-20 SKW5453 OKC → IAH Jul 20, 10:15 UTCJul 20, 11:15 UTC1h 0m
2026-07-20 SKW5281 - Jul 20, 02:50 UTCJul 20, 03:55 UTC1h 5m
2026-07-20 SKW5658 - Jul 20, 00:40 UTCJul 20, 01:20 UTC40m
2026-07-19 SKW5379 - Jul 19, 22:00 UTCJul 19, 22:35 UTC35m
2026-07-19 SKW5531 - Jul 19, 19:40 UTCJul 19, 20:45 UTC1h 5m
2026-07-19 SKW5324 DEN → OKC Jul 19, 16:45 UTCJul 19, 18:05 UTC1h 20m
2026-07-19 SKW4716 CID → DEN Jul 19, 10:40 UTCJul 19, 12:15 UTC1h 35m
2026-07-19 SKW4716 CID → DEN Jul 19, 10:47 UTCJul 19, 12:09 UTC1h 22m
2026-07-18 SKW5677 DEN → CID Jul 18, 20:05 UTCJul 18, 21:40 UTC1h 35m
2026-07-18 SKW5991 - Jul 18, 18:10 UTCJul 18, 18:50 UTC40m
2026-07-18 SKW5476 - Jul 18, 14:30 UTCJul 18, 15:10 UTC40m
2026-07-18 SKW5667 - Jul 18, 12:15 UTCJul 18, 13:30 UTC1h 15m
2026-07-18 SKW4712 ORD → CHA Jul 18, 03:20 UTCJul 18, 04:35 UTC1h 15m
2026-07-18 SKW4712 ORD → CHA Jul 18, 03:13 UTCJul 18, 04:31 UTC1h 18m
2026-07-17 SKW5429 MPJ → DEN Jul 17, 22:25 UTCJul 18, 00:04 UTC1h 40m
2026-07-17 SKW5429 LIT → DEN Jul 17, 22:08 UTCJul 17, 23:59 UTC1h 51m
2026-07-17 SKW5340 - Jul 17, 19:40 UTCJul 17, 20:29 UTC50m
2026-07-17 SKW5525 - Jul 17, 17:15 UTCJul 17, 18:25 UTC1h 10m

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 N166SY page for operator, model, and routing details .

Mode-S A1099F frequently asked

What is Mode-S code A1099F?
A1099F is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N166SY.
Where is Mode-S A1099F registered?
Mode-S code A1099F 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 A1099F broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A1099F, octal 50204637, decimal 10,553,759.
What flights does A1099F operate?
Mode-S A1099F has broadcast 20 distinct callsigns, including SKW5623, SKW6014, SKW5429, SKW6001, SKW5938.