Apparatus

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sensors Mode-S transponder

A851C3

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N635QX · EMBRAER ERJ-170-200 (long wing) · operated by HORIZON AIR INDUSTRIES INC

Hex
A851C3
Octal
52050703
Decimal
11,030,979
Country
US
Tail
N635QX
Type
E75L
No current signal · last broadcast Jul 26, 22:45 UTC
Flights observed
564
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 22:45 UTC

Last known position

Most recent position reported by Mode-S A851C3.

Country allocation

The ICAO 24-bit address A851C3 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
QXE2184 Horizon Air 7 2026-06-07
QXE2320 - 6 2026-06-23
QXE2307 Horizon Air 6 2026-05-21
QXE2057 - 6 2026-07-01
QXE2399 Horizon Air 5 2026-06-03
QXE2267 Horizon Air 5 2026-06-15
QXE2262 Horizon Air 5 2026-07-22
QXE2190 - 5 2026-06-19
QXE2178 - 5 2026-07-08
QXE2125 Horizon Air 5 2026-07-26
QXE2107 Horizon Air 5 2026-07-03
QXE2099 Horizon Air 5 2026-07-20
QXE2090 Horizon Air 5 2026-07-19
QXE2085 Horizon Air 5 2026-07-20
QXE2014 Horizon Air 5 2026-07-24
QXE2416 - 4 2026-06-24
QXE2400 - 4 2026-06-28
QXE2364 Horizon Air 4 2026-05-21
QXE2352 Horizon Air 4 2026-07-24
QXE2350 - 4 2026-07-22

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 QXE2125 SAN → PDX Jul 26, 22:00 UTCJul 26, 22:45 UTC45m
2026-07-26 QXE2181 SEA → GEG Jul 26, 20:20 UTCJul 26, 20:50 UTC30m
2026-07-26 QXE2114 SJC → SEA Jul 26, 17:45 UTCJul 26, 18:45 UTC1h 0m
2026-07-26 QXE2111 SEA → PDX Jul 26, 16:00 UTCJul 26, 17:00 UTC1h 0m
2026-07-26 QXE2165 ANC → BET Jul 26, 13:25 UTCJul 26, 14:05 UTC40m
2026-07-26 QXE2165 ANC → BET Jul 26, 13:23 UTCJul 26, 13:56 UTC33m
2026-07-26 QXE2403 SJC → SEA Jul 26, 05:55 UTCJul 26, 06:25 UTC30m
2026-07-26 QXE2017 AUS → SJC Jul 26, 03:32 UTCJul 26, 03:36 UTC4m
2026-07-26 QXE2017 AUS → SJC Jul 26, 03:15 UTCJul 26, 03:50 UTC35m
2026-07-26 QXE2008 SFO → LAX Jul 26, 01:35 UTCJul 26, 02:10 UTC35m
2026-07-26 QXE2008 SFO → LAX Jul 26, 01:12 UTCJul 26, 02:04 UTC52m
2026-07-25 QXE2275 SJC → PDX Jul 25, 23:05 UTCJul 25, 23:25 UTC20m
2026-07-25 QXE2155 SAN → PAE Jul 25, 21:25 UTCJul 25, 21:45 UTC20m
2026-07-25 QXE2241 PAE → SFO Jul 25, 18:50 UTCJul 25, 19:20 UTC30m
2026-07-25 QXE2241 PAE → SFO Jul 25, 18:49 UTCJul 25, 19:07 UTC18m
2026-07-25 QXE2048 PDX → SFO Jul 25, 17:05 UTCJul 25, 17:30 UTC25m
2026-07-25 QXE2070 SAN → SFO Jul 25, 14:45 UTCJul 25, 15:50 UTC1h 5m
2026-07-25 QXE2034 SJC → PDX Jul 25, 03:20 UTCJul 25, 04:20 UTC1h 0m
2026-07-25 QXE2016 SEA → OAK Jul 25, 01:00 UTCJul 25, 01:35 UTC35m
2026-07-24 QXE2007 SJC → AUS Jul 24, 23:20 UTCJul 24, 23:55 UTC35m
2026-07-24 QXE2014 SBP → PDX Jul 24, 21:30 UTCJul 24, 21:55 UTC25m
2026-07-24 QXE2005 MRY → SEA Jul 24, 19:45 UTCJul 24, 20:20 UTC35m
2026-07-24 QXE2005 MRY → SEA Jul 24, 19:12 UTCJul 24, 20:13 UTC1h 1m
2026-07-24 QXE2012 RDM → SFO Jul 24, 16:15 UTCJul 24, 16:45 UTC30m
2026-07-24 QXE2010 IDA → SEA Jul 24, 06:30 UTCJul 24, 07:05 UTC35m
2026-07-24 QXE2352 PSP → SFO Jul 24, 04:30 UTCJul 24, 04:35 UTC5m
2026-07-24 QXE2352 PSP → SFO Jul 24, 03:20 UTCJul 24, 04:35 UTC1h 15m
2026-07-24 QXE2352 PSP → SFO Jul 24, 03:19 UTCJul 24, 04:14 UTC55m
2026-07-24 QXE2026 SMF → PDX Jul 24, 00:40 UTCJul 24, 02:10 UTC1h 30m
2026-07-23 QXE2025 PDX → SJC Jul 23, 21:50 UTCJul 23, 23:40 UTC1h 50m
2026-07-23 QXE2025 PDX → SJC Jul 23, 21:46 UTCJul 23, 23:36 UTC1h 50m
2026-07-23 QXE2230 LAX → SFO Jul 23, 19:50 UTCJul 23, 20:50 UTC1h 0m
2026-07-23 QXE2141 AUS → SJC Jul 23, 14:30 UTCJul 23, 18:10 UTC3h 40m
2026-07-23 QXE2227 PDX → SEA Jul 23, 12:40 UTCJul 23, 13:00 UTC20m
2026-07-23 QXE2299 RDD → SEA Jul 23, 06:50 UTCJul 23, 07:10 UTC20m
2026-07-23 QXE2352 PSP → SFO Jul 23, 04:10 UTCJul 23, 05:25 UTC1h 15m
2026-07-23 QXE2109 SJC → PDX Jul 23, 01:00 UTCJul 23, 02:05 UTC1h 5m
2026-07-22 QXE2350 GEG → SEA Jul 22, 23:00 UTCJul 22, 23:50 UTC50m
2026-07-22 QXE2349 YYC → SEA Jul 22, 21:30 UTCJul 22, 22:10 UTC40m
2026-07-22 QXE2262 RDM → SEA Jul 22, 19:50 UTCJul 22, 19:55 UTC5m
2026-07-22 QXE2262 RDM → SEA Jul 22, 19:00 UTCJul 22, 19:55 UTC55m
2026-07-22 QXE2262 RDM → SEA Jul 22, 19:00 UTCJul 22, 19:31 UTC31m
2026-07-22 QXE2200 RDM → SEA Jul 22, 17:20 UTCJul 22, 17:55 UTC35m
2026-07-22 QXE2108 RDM → SEA Jul 22, 15:30 UTCJul 22, 15:55 UTC25m
2026-07-22 QXE2432 OAK → SEA Jul 22, 13:55 UTCJul 22, 14:25 UTC30m
2026-07-22 QXE2431 RDD → SEA Jul 22, 12:10 UTCJul 22, 12:35 UTC25m
2026-07-21 QXE2331 SEA → FCA Jul 21, 02:20 UTCJul 21, 03:35 UTC1h 15m
2026-07-21 QXE2258 SEA → PDX Jul 21, 00:05 UTCJul 21, 01:20 UTC1h 15m
2026-07-20 QXE2169 ANC → BET Jul 20, 20:30 UTCJul 20, 23:05 UTC2h 35m
2026-07-20 QXE2146 - Jul 20, 18:10 UTCJul 20, 18:55 UTC45m

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 N635QX page for operator, model, and routing details .

Mode-S A851C3 frequently asked

What is Mode-S code A851C3?
A851C3 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N635QX.
Where is Mode-S A851C3 registered?
Mode-S code A851C3 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 A851C3 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 22:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A851C3, octal 52050703, decimal 11,030,979.
What flights does A851C3 operate?
Mode-S A851C3 has broadcast 20 distinct callsigns, including QXE2184, QXE2320, QXE2307, QXE2057, QXE2399.