Apparatus

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sensors Mode-S transponder

A85931

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N637QX · EMBRAER ERJ-170-200 (long wing) · operated by HORIZON AIR INDUSTRIES INC

Hex
A85931
Octal
52054461
Decimal
11,032,881
Country
US
Tail
N637QX
Type
E75L
No current signal · last broadcast Jul 26, 20:10 UTC
Flights observed
791
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 20:10 UTC

Last known position

Most recent position reported by Mode-S A85931.

Country allocation

The ICAO 24-bit address A85931 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
QXE2403 Horizon Air 10 2026-06-02
QXE2133 Horizon Air 8 2026-07-21
QXE2389 Horizon Air 7 2026-06-03
QXE2364 Horizon Air 7 2026-07-26
QXE2123 - 7 2026-07-17
QXE2117 - 7 2026-07-09
QXE2102 Horizon Air 7 2026-06-13
QXE2038 Horizon Air 7 2026-06-12
QXE2456 - 6 2026-07-15
QXE2400 Horizon Air 6 2026-07-25
QXE2371 - 6 2026-07-13
QXE2249 - 6 2026-07-15
QXE2166 - 6 2026-07-07
QXE2125 - 6 2026-07-09
QXE2115 - 6 2026-06-26
QXE2097 - 6 2026-06-26
QXE2081 - 6 2026-07-13
QXE2068 Horizon Air 6 2026-07-21
QXE2053 - 6 2026-07-10
QXE2025 - 6 2026-07-01

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 QXE2145 FAI → ANC Jul 26, 18:00 UTCJul 26, 19:25 UTC1h 25m
2026-07-26 QXE2144 SJC → PDX Jul 26, 15:40 UTCJul 26, 16:45 UTC1h 5m
2026-07-26 QXE2067 PUW → SEA Jul 26, 12:55 UTCJul 26, 13:40 UTC45m
2026-07-26 QXE2364 SEA → PUW Jul 26, 06:07 UTCJul 26, 06:37 UTC30m
2026-07-26 QXE2364 SEA → PUW Jul 26, 05:55 UTCJul 26, 06:35 UTC41m
2026-07-26 QXE2084 PAE → SFO Jul 26, 02:45 UTCJul 26, 03:55 UTC1h 10m
2026-07-25 QXE2353 PSP → SFO Jul 25, 23:15 UTCJul 26, 00:05 UTC50m
2026-07-25 QXE2400 SEA → GEG Jul 25, 21:05 UTCJul 25, 21:55 UTC50m
2026-07-25 QXE2400 SEA → GEG Jul 25, 21:00 UTCJul 25, 21:43 UTC43m
2026-07-25 QXE2400 SEA → GEG Jul 25, 19:15 UTCJul 25, 19:55 UTC40m
2026-07-25 QXE2108 RDM → SEA Jul 25, 15:40 UTCJul 25, 16:10 UTC30m
2026-07-25 QXE2432 OAK → SEA Jul 25, 13:50 UTCJul 25, 14:20 UTC30m
2026-07-25 QXE2431 RDD → SEA Jul 25, 12:10 UTCJul 25, 12:40 UTC30m
2026-07-25 QXE2377 BZN → BOI Jul 25, 06:45 UTCJul 25, 07:20 UTC35m
2026-07-25 QXE2421 LAX → PAE Jul 25, 04:40 UTCJul 25, 05:15 UTC35m
2026-07-25 QXE2421 LAX → PAE Jul 25, 04:39 UTCJul 25, 04:59 UTC20m
2026-07-25 QXE2056 SEA → SJC Jul 25, 01:05 UTCJul 25, 02:40 UTC1h 35m
2026-07-24 QXE2056 SEA → SJC Jul 24, 22:00 UTCJul 24, 23:50 UTC1h 50m
2026-07-24 QXE2209 LAX → SJC Jul 24, 19:35 UTCJul 24, 20:30 UTC55m
2026-07-24 QXE2089 GEG → PDX Jul 24, 17:40 UTCJul 24, 18:30 UTC50m
2026-07-24 QXE2178 PDX → ONT Jul 24, 14:40 UTCJul 24, 16:25 UTC1h 45m
2026-07-24 QXE2029 LAX → SFO Jul 24, 01:10 UTCJul 24, 03:05 UTC1h 55m
2026-07-23 QXE2297 PHX → PAE Jul 23, 22:40 UTCJul 24, 00:20 UTC1h 40m
2026-07-23 QXE2054 OAK → PDX Jul 23, 20:30 UTCJul 23, 22:00 UTC1h 30m
2026-07-23 QXE9985 GEG → SFO Jul 23, 16:25 UTCJul 23, 17:55 UTC1h 30m
2026-07-21 QXE2307 GEG → SFO Jul 21, 23:25 UTCJul 22, 00:30 UTC1h 5m
2026-07-21 QXE2133 PDX → SFO Jul 21, 18:00 UTCJul 21, 18:15 UTC15m
2026-07-21 QXE2133 PDX → SFO Jul 21, 17:59 UTCJul 21, 19:43 UTC1h 44m
2026-07-21 QXE2068 SFO → PAE Jul 21, 15:05 UTCJul 21, 17:10 UTC2h 5m
2026-07-21 QXE2148 LAX → SFO Jul 21, 12:15 UTCJul 21, 13:35 UTC1h 20m
2026-07-21 QXE2147 SFO → LAX Jul 21, 04:10 UTCJul 21, 05:15 UTC1h 5m
2026-07-21 QXE2308 SJC → PDX Jul 21, 01:10 UTCJul 21, 02:40 UTC1h 30m
2026-07-21 QXE2308 SJC → PDX Jul 21, 01:10 UTCJul 21, 02:36 UTC1h 26m
2026-07-20 QXE2307 GEG → SFO Jul 20, 22:55 UTCJul 20, 23:55 UTC59m
2026-07-20 QXE2205 RNO → LAX Jul 20, 21:00 UTCJul 20, 21:25 UTC25m
2026-07-20 QXE2205 RNO → LAX Jul 20, 21:04 UTCJul 20, 21:21 UTC17m
2026-07-20 QXE2333 SFO → SAN Jul 20, 17:35 UTCJul 20, 19:10 UTC1h 35m
2026-07-20 QXE2333 SFO → SAN Jul 20, 15:05 UTCJul 20, 16:35 UTC1h 30m
2026-07-20 QXE2218 MSO → SEA Jul 20, 02:55 UTCJul 20, 03:25 UTC30m
2026-07-20 QXE2172 SEA → YKM Jul 20, 01:40 UTCJul 20, 02:05 UTC25m
2026-07-20 QXE2172 SEA → YKM Jul 20, 01:46 UTCJul 20, 02:05 UTC19m
2026-07-19 QXE2387 SJC → SAN Jul 19, 04:00 UTCJul 19, 04:35 UTC35m
2026-07-19 QXE2016 - Jul 19, 00:55 UTCJul 19, 01:30 UTC35m
2026-07-18 QXE2007 KEH → YVR Jul 18, 22:55 UTCJul 18, 23:20 UTC25m
2026-07-18 QXE2007 SEA → YVR Jul 18, 22:55 UTCJul 18, 23:19 UTC24m
2026-07-18 QXE2000 - Jul 18, 21:10 UTCJul 18, 21:35 UTC25m
2026-07-18 QXE2001 - Jul 18, 19:50 UTCJul 18, 20:05 UTC15m
2026-07-18 QXE2153 - Jul 18, 13:25 UTCJul 18, 14:25 UTC1h 0m
2026-07-18 QXE2154 - Jul 18, 04:00 UTCJul 18, 04:50 UTC50m
2026-07-18 QXE2132 - Jul 18, 00:55 UTCJul 18, 02:14 UTC1h 20m

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 N637QX page for operator, model, and routing details .

Mode-S A85931 frequently asked

What is Mode-S code A85931?
A85931 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N637QX.
Where is Mode-S A85931 registered?
Mode-S code A85931 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 A85931 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 20:10 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A85931, octal 52054461, decimal 11,032,881.
What flights does A85931 operate?
Mode-S A85931 has broadcast 20 distinct callsigns, including QXE2403, QXE2133, QXE2389, QXE2364, QXE2123.