Apparatus

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sensors Mode-S transponder

A8557A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N636QX · EMBRAER ERJ-170-200 (long wing) · operated by HORIZON AIR INDUSTRIES INC

Hex
A8557A
Octal
52052572
Decimal
11,031,930
Country
US
Tail
N636QX
Type
E75L
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
552
Distinct callsigns
20
Country
US
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S A8557A.

Country allocation

The ICAO 24-bit address A8557A 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
QXE2158 - 11 2026-07-11
QXE2347 - 7 2026-07-18
QXE2090 Horizon Air 7 2026-05-26
QXE2340 Horizon Air 6 2026-05-21
QXE2276 - 6 2026-07-15
QXE2007 - 6 2026-07-05
QXE2509 Horizon Air 5 2026-05-12
QXE2365 Horizon Air 5 2026-05-11
QXE2346 - 5 2026-07-17
QXE2303 Horizon Air 5 2026-05-23
QXE2301 Horizon Air 5 2026-05-23
QXE2297 Horizon Air 5 2026-05-22
QXE2271 - 5 2026-07-15
QXE2268 - 5 2026-07-14
QXE2191 Horizon Air 5 2026-07-24
QXE2186 Horizon Air 5 2026-05-17
QXE2179 Horizon Air 5 2026-07-18
QXE2103 - 5 2026-07-11
QXE2057 Horizon Air 5 2026-05-25
QXE2056 Horizon Air 5 2026-07-09

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 QXE2176 AKN → ANC Jul 26, 21:05 UTCJul 26, 21:45 UTC40m
2026-07-26 QXE2317 PAE → SFO Jul 26, 18:00 UTCJul 26, 20:05 UTC2h 5m
2026-07-26 QXE2002 PSP → SFO Jul 26, 15:50 UTCJul 26, 16:45 UTC55m
2026-07-26 QXE2009 PHX → SFO Jul 26, 03:20 UTCJul 26, 03:55 UTC35m
2026-07-25 QXE2310 SEA → YVR Jul 25, 23:50 UTCJul 26, 00:55 UTC1h 5m
2026-07-25 QXE2311 YVR → SEA Jul 25, 21:30 UTCJul 25, 22:15 UTC45m
2026-07-25 QXE2311 YVR → SEA Jul 25, 21:15 UTCJul 25, 22:33 UTC1h 18m
2026-07-25 QXE2013 PDX → BZN Jul 25, 19:15 UTCJul 25, 19:45 UTC30m
2026-07-25 QXE2004 PDX → BOI Jul 25, 17:17 UTCJul 25, 17:53 UTC36m
2026-07-25 QXE2004 PDX → BOI Jul 25, 17:20 UTCJul 25, 17:55 UTC35m
2026-07-25 QXE2027 PDX → SFO Jul 25, 14:25 UTCJul 25, 15:15 UTC50m
2026-07-25 QXE2162 SFO → SNA Jul 25, 04:10 UTCJul 25, 05:45 UTC1h 35m
2026-07-25 QXE2284 SEA → FCA Jul 25, 01:15 UTCJul 25, 03:10 UTC1h 55m
2026-07-24 QXE2061 SBP → SEA Jul 24, 23:00 UTCJul 25, 00:00 UTC1h 0m
2026-07-24 QXE2400 SEA → GEG Jul 24, 21:20 UTCJul 24, 22:05 UTC45m
2026-07-24 QXE2400 SEA → GEG Jul 24, 19:40 UTCJul 24, 20:25 UTC45m
2026-07-24 QXE2325 PDX → SFO Jul 24, 17:25 UTCJul 24, 18:30 UTC1h 5m
2026-07-24 QXE2202 ONT → PDX Jul 24, 14:05 UTCJul 24, 15:05 UTC1h 0m
2026-07-24 QXE2227 PDX → SEA Jul 24, 12:30 UTCJul 24, 12:55 UTC25m
2026-07-24 QXE2227 PDX → SEA Jul 24, 12:24 UTCJul 24, 12:47 UTC23m
2026-07-24 QXE2299 RDD → SEA Jul 24, 07:45 UTCJul 24, 08:00 UTC15m
2026-07-24 QXE2191 SAN → SFO Jul 24, 05:20 UTCJul 24, 06:45 UTC1h 25m
2026-07-24 QXE2191 SAN → SFO Jul 24, 02:40 UTCJul 24, 04:30 UTC1h 50m
2026-07-23 QXE2191 SAN → SFO Jul 23, 22:00 UTCJul 24, 00:55 UTC2h 55m
2026-07-23 QXE2069 SFO → PDX Jul 23, 20:05 UTCJul 23, 20:45 UTC40m
2026-07-23 QXE2135 PAE → LAX Jul 23, 14:42 UTCJul 23, 15:26 UTC44m
2026-07-23 QXE2135 PAE → LAX Jul 23, 14:40 UTCJul 23, 15:25 UTC45m
2026-07-23 QXE2065 PDX → SFO Jul 23, 12:25 UTCJul 23, 13:05 UTC40m
2026-07-23 QXE2295 RDM → PDX Jul 23, 03:45 UTCJul 23, 07:05 UTC3h 20m
2026-07-23 QXE2295 RDM → PDX Jul 23, 03:44 UTCJul 23, 07:04 UTC3h 20m
2026-07-22 QXE2294 RDM → SEA Jul 22, 22:55 UTCJul 23, 02:40 UTC3h 45m
2026-07-22 QXE2020 SFO → PHX Jul 22, 19:30 UTCJul 22, 21:45 UTC2h 15m
2026-07-22 QXE2020 SFO → PHX Jul 22, 19:25 UTCJul 22, 21:45 UTC2h 20m
2026-07-22 QXE2270 SEA → FCA Jul 22, 15:55 UTCJul 22, 18:30 UTC2h 35m
2026-07-22 QXE2270 SEA → FCA Jul 22, 16:00 UTCJul 22, 18:22 UTC2h 22m
2026-07-22 QXE2083 SEA → OAK Jul 22, 04:15 UTCJul 22, 05:25 UTC1h 10m
2026-07-21 QXE2062 OAK → PDX Jul 21, 22:25 UTCJul 22, 03:20 UTC4h 55m
2026-07-21 QXE2139 SNA → PDX Jul 21, 19:05 UTCJul 21, 21:00 UTC1h 55m
2026-07-21 QXE2139 SNA → PDX Jul 21, 19:00 UTCJul 21, 20:49 UTC1h 49m
2026-07-21 QXE2249 PDX → SEA Jul 21, 16:25 UTCJul 21, 17:55 UTC1h 30m
2026-07-21 QXE2112 - Jul 21, 05:55 UTCJul 21, 07:25 UTC1h 30m
2026-07-21 QXE2304 YVR → SEA Jul 21, 00:45 UTCJul 21, 02:00 UTC1h 15m
2026-07-21 QXE2304 YVR → SEA Jul 21, 00:42 UTCJul 21, 01:59 UTC1h 17m
2026-07-20 QXE2035 LAX → PDX Jul 20, 22:25 UTCJul 20, 23:55 UTC1h 30m
2026-07-20 QXE2042 - Jul 20, 19:10 UTCJul 20, 20:15 UTC1h 5m
2026-07-20 QXE2168 SFO → BUR Jul 20, 15:45 UTCJul 20, 17:35 UTC1h 50m
2026-07-20 QXE2267 - Jul 20, 13:15 UTCJul 20, 14:05 UTC50m
2026-07-20 QXE2312 SAN → SBP Jul 20, 06:18 UTCJul 20, 06:58 UTC40m
2026-07-20 QXE2312 - Jul 20, 06:20 UTCJul 20, 07:00 UTC40m
2026-07-20 QXE2213 SJC → SAN Jul 20, 04:10 UTCJul 20, 05:15 UTC1h 5m

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 N636QX page for operator, model, and routing details .

Mode-S A8557A frequently asked

What is Mode-S code A8557A?
A8557A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N636QX.
Where is Mode-S A8557A registered?
Mode-S code A8557A 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 A8557A 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 A8557A, octal 52052572, decimal 11,031,930.
What flights does A8557A operate?
Mode-S A8557A has broadcast 20 distinct callsigns, including QXE2158, QXE2347, QXE2090, QXE2340, QXE2276.