Apparatus

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sensors Mode-S transponder

A2644A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N253SY · EMBRAER ERJ-170-200 (long wing) · operated by SKYWEST AIRLINES INC

Hex
A2644A
Octal
50462112
Decimal
10,642,506
Country
US
Tail
N253SY
Type
E75L
No current signal · last broadcast Jul 26, 22:30 UTC
Flights observed
665
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:30 UTC

Last known position

Most recent position reported by Mode-S A2644A.

Country allocation

The ICAO 24-bit address A2644A 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
SKW3991 SkyWest Airlines 12 2026-07-19
SKW4119 - 10 2026-07-15
SKW4099 - 9 2026-06-29
SKW3833 SkyWest Airlines 9 2026-07-06
SKW3903 - 8 2026-06-25
SKW3902 - 8 2026-07-14
SKW3789 SkyWest Airlines 8 2026-07-19
SKW3779 SkyWest Airlines 8 2026-07-21
SKW3681 - 8 2026-06-23
SKW3828 - 7 2026-07-07
SKW3755 - 7 2026-07-13
SKW3669 SkyWest Airlines 7 2026-05-30
SKW3620 - 7 2026-07-04
SKW4444 SkyWest Airlines 6 2026-06-25
SKW4077 - 6 2026-07-15
SKW3932 SkyWest Airlines 6 2026-07-21
SKW3894 - 6 2026-07-13
SKW3855 SkyWest Airlines 6 2026-07-20
SKW3801 SkyWest Airlines 6 2026-07-21
SKW3777 - 6 2026-06-19

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 SKW4053 ATL → EVV Jul 26, 22:10 UTCJul 26, 22:30 UTC20m
2026-07-26 SKW4053 ATL → EVV Jul 26, 20:20 UTCJul 26, 21:10 UTC50m
2026-07-26 SKW3747 OAK → LAX Jul 26, 16:50 UTCJul 26, 18:55 UTC2h 5m
2026-07-26 SKW3747 OAK → LAX Jul 26, 13:40 UTCJul 26, 15:30 UTC1h 50m
2026-07-26 SKW3734 LGA → OKC Jul 26, 00:10 UTCJul 26, 02:15 UTC2h 5m
2026-07-25 SKW3734 LGA → OKC Jul 25, 21:05 UTCJul 25, 23:20 UTC2h 15m
2026-07-25 SKW3747 OAK → LAX Jul 25, 17:00 UTCJul 25, 19:05 UTC2h 5m
2026-07-25 SKW3747 OAK → LAX Jul 25, 13:50 UTCJul 25, 15:50 UTC2h 0m
2026-07-24 SKW4027 BOS → CLE Jul 24, 22:30 UTCJul 25, 00:35 UTC2h 5m
2026-07-24 SKW4027 BOS → CLE Jul 24, 19:10 UTCJul 24, 21:15 UTC2h 5m
2026-07-24 SKW4101 SJC → SLC Jul 24, 15:40 UTCJul 24, 17:50 UTC2h 10m
2026-07-24 SKW4101 SJC → SLC Jul 24, 12:40 UTCJul 24, 14:45 UTC2h 5m
2026-07-24 SKW3577 GSP → DTW Jul 24, 01:00 UTCJul 24, 02:30 UTC1h 30m
2026-07-23 SKW3577 GSP → DTW Jul 23, 22:35 UTCJul 24, 00:05 UTC1h 30m
2026-07-23 SKW3955 ATL → MGM Jul 23, 16:55 UTCJul 23, 19:25 UTC2h 30m
2026-07-23 SKW4538 SLC → GEG Jul 23, 00:10 UTCJul 23, 01:30 UTC1h 20m
2026-07-22 SKW4538 SLC → GEG Jul 22, 21:50 UTCJul 22, 23:10 UTC1h 20m
2026-07-22 SKW4538 SLC → GEG Jul 22, 21:59 UTCJul 22, 23:04 UTC1h 5m
2026-07-22 SKW4138 FAT → SLC Jul 22, 13:30 UTCJul 22, 14:40 UTC1h 10m
2026-07-22 SKW3774 SLC → FAT Jul 22, 04:40 UTCJul 22, 05:10 UTC30m
2026-07-21 SKW3801 JFK → IAD Jul 21, 20:55 UTCJul 21, 22:30 UTC1h 35m
2026-07-21 SKW3779 OAK → SLC Jul 21, 18:45 UTCJul 21, 20:00 UTC1h 15m
2026-07-21 SKW3695 ORD → BOS Jul 21, 14:20 UTCJul 21, 16:35 UTC2h 15m
2026-07-21 SKW3932 MSP → MOT Jul 21, 03:55 UTCJul 21, 05:25 UTC1h 30m
2026-07-21 SKW3932 MSP → MOT Jul 21, 03:00 UTCJul 21, 03:50 UTC50m
2026-07-21 SKW3857 SJC → SEA Jul 21, 00:55 UTCJul 21, 01:45 UTC50m
2026-07-20 SKW3857 SJC → SEA Jul 20, 23:00 UTCJul 20, 23:40 UTC40m
2026-07-20 SKW4070 - Jul 20, 19:10 UTCJul 20, 21:10 UTC2h 0m
2026-07-20 SKW4070 SEA → ONT Jul 20, 15:50 UTCJul 20, 18:10 UTC2h 20m
2026-07-20 SKW4128 EUG → SEA Jul 20, 13:30 UTCJul 20, 14:15 UTC45m
2026-07-20 SKW3855 MSP → CID Jul 20, 05:45 UTCJul 20, 06:30 UTC45m
2026-07-20 SKW3855 MSP → CID Jul 20, 05:49 UTCJul 20, 06:30 UTC41m
2026-07-20 SKW3832 GEG → SEA Jul 20, 03:10 UTCJul 20, 04:05 UTC55m
2026-07-20 SKW3832 GEG → SEA Jul 20, 01:25 UTCJul 20, 02:10 UTC45m
2026-07-19 SKW3789 SJC → SEA Jul 19, 22:10 UTCJul 19, 23:40 UTC1h 30m
2026-07-19 SKW3789 SJC → SEA Jul 19, 22:04 UTCJul 19, 23:40 UTC1h 36m
2026-07-19 SKW168F SEA → SJC Jul 19, 19:05 UTCJul 19, 21:10 UTC2h 5m
2026-07-19 SKW156H GEG → SEA Jul 19, 16:45 UTCJul 19, 17:21 UTC36m
2026-07-19 SKW156H GEG → SEA Jul 19, 16:40 UTCJul 19, 17:35 UTC55m
2026-07-19 SKW3830 OAK → LAX Jul 19, 15:00 UTCJul 19, 15:40 UTC40m
2026-07-19 SKW3991 ATL → HPN Jul 19, 05:15 UTCJul 19, 06:45 UTC1h 30m
2026-07-19 SKW3991 ATL → HPN Jul 19, 05:01 UTCJul 19, 06:35 UTC1h 34m
2026-07-19 SKW3991 ATL → HPN Jul 19, 01:50 UTCJul 19, 03:50 UTC2h 0m
2026-07-18 SKW3789 SJC → SEA Jul 18, 22:35 UTCJul 19, 00:05 UTC1h 30m
2026-07-18 SKW3789 SJC → SEA Jul 18, 22:40 UTCJul 19, 00:05 UTC1h 25m
2026-07-18 SKW168F SEA → SJC Jul 18, 20:00 UTCJul 18, 21:50 UTC1h 50m
2026-07-18 SKW3750 - Jul 18, 17:20 UTCJul 18, 18:25 UTC1h 5m
2026-07-18 SKW3750 SEA → BOI Jul 18, 14:30 UTCJul 18, 15:30 UTC1h 0m
2026-07-18 SKW4100 SJC → SEA Jul 18, 04:00 UTCJul 18, 05:35 UTC1h 35m
2026-07-18 SKW4100 SEA → SJC Jul 18, 01:10 UTCJul 18, 03:00 UTC1h 51m

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 N253SY page for operator, model, and routing details .

Mode-S A2644A frequently asked

What is Mode-S code A2644A?
A2644A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N253SY.
Where is Mode-S A2644A registered?
Mode-S code A2644A 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 A2644A broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:30 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A2644A, octal 50462112, decimal 10,642,506.
What flights does A2644A operate?
Mode-S A2644A has broadcast 20 distinct callsigns, including SKW3991, SKW4119, SKW4099, SKW3833, SKW3903.