Apparatus

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sensors Mode-S transponder

A871D4

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N643QX · EMBRAER ERJ-170-200 (long wing) · operated by HORIZON AIR INDUSTRIES INC

Hex
A871D4
Octal
52070724
Decimal
11,039,188
Country
US
Tail
N643QX
Type
E75L
No current signal · last broadcast Jul 26, 23:00 UTC
Flights observed
779
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 23:00 UTC

Last known position

Most recent position reported by Mode-S A871D4.

Country allocation

The ICAO 24-bit address A871D4 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
QXE2307 - 11 2026-07-07
QXE2164 - 8 2026-06-28
QXE2152 Horizon Air 8 2026-06-05
QXE2443 Horizon Air 7 2026-06-08
QXE2268 - 7 2026-07-16
QXE2148 - 7 2026-07-08
QXE2117 - 7 2026-06-28
QXE2094 - 7 2026-07-01
QXE2003 Horizon Air 7 2026-06-02
QXE2293 Horizon Air 6 2026-07-01
QXE2288 - 6 2026-07-17
QXE2277 - 6 2026-07-21
QXE2166 - 6 2026-07-06
QXE2165 - 6 2026-06-28
QXE2093 - 6 2026-07-05
QXE2440 Horizon Air 5 2026-05-19
QXE2421 Horizon Air 5 2026-07-23
QXE2309 Horizon Air 5 2026-07-01
QXE2306 Horizon Air 5 2026-07-06
QXE2270 Horizon Air 5 2026-07-26

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 QXE2119 SAN → SFO Jul 26, 22:30 UTCJul 26, 23:00 UTC30m
2026-07-26 QXE2020 SFO → PHX Jul 26, 19:00 UTCJul 26, 21:00 UTC2h 0m
2026-07-26 QXE2270 SEA → FCA Jul 26, 15:00 UTCJul 26, 17:40 UTC2h 40m
2026-07-26 QXE2189 SAN → PAE Jul 26, 03:53 UTCJul 26, 06:11 UTC2h 18m
2026-07-26 QXE2189 SAN → PAE Jul 26, 03:55 UTCJul 26, 06:20 UTC2h 25m
2026-07-26 QXE2406 FAI → ANC Jul 26, 01:20 UTCJul 26, 02:45 UTC1h 25m
2026-07-25 QXE2405 SJC → PDX Jul 25, 22:50 UTCJul 26, 00:05 UTC1h 15m
2026-07-25 QXE9555 OKC → PDX Jul 25, 20:40 UTCJul 25, 21:35 UTC55m
2026-07-25 QXE9555 OKC → PDX Jul 25, 20:36 UTCJul 25, 21:24 UTC48m
2026-07-25 QXE2107 PAE → SFO Jul 25, 02:35 UTCJul 25, 03:15 UTC40m
2026-07-25 QXE2163 SJC → LAX Jul 25, 01:00 UTCJul 25, 01:55 UTC55m
2026-07-24 QXE2167 LAX → SJC Jul 24, 23:25 UTCJul 25, 00:05 UTC40m
2026-07-24 QXE2173 SFO → PDX Jul 24, 21:40 UTCJul 24, 22:10 UTC30m
2026-07-24 QXE2216 BOI → SFO Jul 24, 17:50 UTCJul 24, 20:20 UTC2h 30m
2026-07-24 QXE2216 BOI → SFO Jul 24, 17:50 UTCJul 24, 20:18 UTC2h 28m
2026-07-24 QXE2215 SAN → SFO Jul 24, 14:05 UTCJul 24, 16:40 UTC2h 35m
2026-07-24 QXE2387 SJC → SAN Jul 24, 03:40 UTCJul 24, 04:10 UTC30m
2026-07-24 QXE2366 SFO → LAX Jul 24, 01:45 UTCJul 24, 02:25 UTC40m
2026-07-24 QXE2367 SEA → PSC Jul 24, 00:10 UTCJul 24, 00:40 UTC30m
2026-07-23 QXE2359 PDX → MSO Jul 23, 22:20 UTCJul 23, 22:45 UTC25m
2026-07-23 QXE2359 PDX → MSO Jul 23, 22:16 UTCJul 23, 22:35 UTC19m
2026-07-23 QXE2149 SFO → LAX Jul 23, 20:40 UTCJul 23, 21:10 UTC30m
2026-07-23 QXE2159 - Jul 23, 18:20 UTCJul 23, 19:25 UTC1h 5m
2026-07-23 QXE2031 MFR → SEA Jul 23, 16:00 UTCJul 23, 16:45 UTC45m
2026-07-23 QXE2031 MFR → SEA Jul 23, 15:59 UTCJul 23, 16:45 UTC46m
2026-07-23 QXE2404 PDX → GEG Jul 23, 14:10 UTCJul 23, 14:55 UTC45m
2026-07-23 QXE2377 BZN → BOI Jul 23, 07:20 UTCJul 23, 07:45 UTC25m
2026-07-23 QXE2421 LAX → PAE Jul 23, 05:55 UTCJul 23, 06:30 UTC35m
2026-07-23 QXE2421 LAX → PAE Jul 23, 05:52 UTCJul 23, 06:21 UTC29m
2026-07-23 QXE2331 SEA → FCA Jul 23, 03:40 UTCJul 23, 04:50 UTC1h 10m
2026-07-23 QXE2258 SEA → PDX Jul 23, 00:25 UTCJul 23, 01:40 UTC1h 15m
2026-07-22 QXE2169 ANC → BET Jul 22, 20:35 UTCJul 22, 23:05 UTC2h 30m
2026-07-22 QXE2169 ANC → BET Jul 22, 20:18 UTCJul 22, 22:55 UTC2h 37m
2026-07-22 QXE2146 - Jul 22, 18:05 UTCJul 22, 19:00 UTC55m
2026-07-22 QXE2146 PDX → MSO Jul 22, 18:03 UTCJul 22, 19:11 UTC1h 8m
2026-07-22 QXE2398 SMF → SAN Jul 22, 13:15 UTCJul 22, 16:50 UTC3h 35m
2026-07-22 QXE2398 SMF → SAN Jul 22, 13:14 UTCJul 22, 16:36 UTC3h 22m
2026-07-22 QXE9987 PDX → SFO Jul 22, 04:35 UTCJul 22, 05:25 UTC50m
2026-07-22 QXE9987 PDX → SFO Jul 22, 04:40 UTCJul 22, 05:32 UTC52m
2026-07-21 QXE2073 - Jul 21, 15:15 UTCJul 21, 16:10 UTC55m
2026-07-21 QXE2060 FAI → ANC Jul 21, 13:00 UTCJul 21, 13:50 UTC50m
2026-07-21 QXE2060 FAI → ANC Jul 21, 12:59 UTCJul 21, 13:42 UTC43m
2026-07-21 QXE2277 ANC → FAI Jul 21, 07:15 UTCJul 21, 07:38 UTC23m
2026-07-21 QXE2277 ANC → FAI Jul 21, 07:00 UTCJul 21, 07:55 UTC55m
2026-07-21 QXE2130 LAX → SEA Jul 21, 03:30 UTCJul 21, 05:00 UTC1h 30m
2026-07-21 QXE2226 SMF → SEA Jul 21, 00:45 UTCJul 21, 01:55 UTC1h 10m
2026-07-20 QXE2039 PHX → SFO Jul 20, 21:55 UTCJul 20, 23:10 UTC1h 15m
2026-07-20 QXE2039 PHX → SFO Jul 20, 22:10 UTCJul 20, 22:56 UTC46m
2026-07-20 QXE2038 ANC → DLG Jul 20, 20:19 UTCJul 20, 20:55 UTC36m
2026-07-20 QXE2038 - Jul 20, 20:05 UTCJul 20, 20:55 UTC50m

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 N643QX page for operator, model, and routing details .

Mode-S A871D4 frequently asked

What is Mode-S code A871D4?
A871D4 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N643QX.
Where is Mode-S A871D4 registered?
Mode-S code A871D4 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 A871D4 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 23:00 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A871D4, octal 52070724, decimal 11,039,188.
What flights does A871D4 operate?
Mode-S A871D4 has broadcast 20 distinct callsigns, including QXE2307, QXE2164, QXE2152, QXE2443, QXE2268.