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 1h ago
Flights observed
461
Distinct callsigns
20
Country
US
Last broadcast
1h ago

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
QXE2090 Horizon Air 7 2026-05-26
QXE2340 Horizon Air 6 2026-05-21
QXE2007 - 6 2026-07-05
QXE2509 Horizon Air 5 2026-05-12
QXE2365 Horizon Air 5 2026-05-11
QXE2303 Horizon Air 5 2026-05-23
QXE2301 Horizon Air 5 2026-05-23
QXE2297 Horizon Air 5 2026-05-22
QXE2276 Horizon Air 5 2026-05-10
QXE2186 Horizon Air 5 2026-05-17
QXE2103 - 5 2026-07-11
QXE2057 Horizon Air 5 2026-05-25
QXE2056 Horizon Air 5 2026-07-09
QXE2499 Horizon Air 4 2026-05-26
QXE2445 Horizon Air 4 2026-05-26
QXE2444 Horizon Air 4 2026-04-25
QXE2403 Horizon Air 4 2026-05-12
QXE2385 Horizon Air 4 2026-05-26
QXE2277 - 4 2026-07-11

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-14 QXE2304 OAK → PDX Jul 14, 00:45 UTCJul 14, 01:55 UTC1h 10m
2026-07-13 QXE2035 - Jul 13, 22:15 UTCJul 13, 23:50 UTC1h 35m
2026-07-13 QXE2035 PDX → OAK Jul 13, 22:12 UTCJul 13, 23:48 UTC1h 36m
2026-07-13 QXE2216 - Jul 13, 17:45 UTCJul 13, 20:10 UTC2h 25m
2026-07-13 QXE2215 - Jul 13, 14:10 UTCJul 13, 16:45 UTC2h 35m
2026-07-13 QXE2053 EUG → PDX Jul 13, 12:25 UTCJul 13, 12:45 UTC20m
2026-07-13 QXE2088 - Jul 13, 05:20 UTCJul 13, 05:50 UTC30m
2026-07-13 QXE2304 OAK → PDX Jul 13, 00:45 UTCJul 13, 01:55 UTC1h 10m
2026-07-12 QXE2035 - Jul 12, 22:15 UTCJul 12, 23:50 UTC1h 35m
2026-07-12 QXE2209 - Jul 12, 19:40 UTCJul 12, 20:45 UTC1h 5m
2026-07-12 QXE2089 - Jul 12, 17:35 UTCJul 12, 18:30 UTC55m
2026-07-12 QXE2398 ANC → PDX Jul 12, 13:05 UTCJul 12, 16:40 UTC3h 35m
2026-07-12 QXE2099 FAI → ANC Jul 12, 04:54 UTCJul 12, 05:19 UTC25m
2026-07-12 QXE2099 FAI → ANC Jul 12, 04:45 UTCJul 12, 05:30 UTC45m
2026-07-12 QXE2085 ANC → FAI Jul 12, 03:20 UTCJul 12, 04:01 UTC40m
2026-07-12 QXE2085 ANC → FAI Jul 12, 03:17 UTCJul 12, 04:02 UTC45m
2026-07-12 QXE2102 - Jul 12, 01:25 UTCJul 12, 02:10 UTC45m
2026-07-11 QXE2103 - Jul 11, 23:40 UTCJul 12, 00:25 UTC45m
2026-07-11 QXE2103 ANC → FAI Jul 11, 23:39 UTCJul 12, 00:27 UTC48m
2026-07-11 QXE2160 AKN → ANC Jul 11, 21:35 UTCJul 11, 22:20 UTC45m
2026-07-11 QXE2158 ANC → AKN Jul 11, 19:30 UTCJul 11, 20:25 UTC55m
2026-07-11 QXE2158 ANC → AKN Jul 11, 19:30 UTCJul 11, 20:22 UTC52m
2026-07-11 QXE2033 - Jul 11, 17:35 UTCJul 11, 18:30 UTC55m
2026-07-11 QXE2032 SEA → SJC Jul 11, 15:35 UTCJul 11, 16:15 UTC40m
2026-07-11 QXE2060 FAI → ANC Jul 11, 13:00 UTCJul 11, 13:50 UTC50m
2026-07-11 QXE2277 ANC → FAI Jul 11, 07:00 UTCJul 11, 07:40 UTC40m
2026-07-11 QXE2130 OTZ → ANC Jul 11, 02:25 UTCJul 11, 03:45 UTC1h 20m
2026-07-11 QXE2226 ANC → OTZ Jul 11, 00:05 UTCJul 11, 01:25 UTC1h 20m
2026-07-10 QXE2160 AKN → ANC Jul 10, 22:20 UTCJul 10, 23:05 UTC45m
2026-07-10 QXE2158 ANC → AKN Jul 10, 20:35 UTCJul 10, 21:25 UTC50m
2026-07-10 QXE2074 - Jul 10, 18:00 UTCJul 10, 19:05 UTC1h 5m
2026-07-10 QXE2073 SFO → LAX Jul 10, 15:35 UTCJul 10, 16:30 UTC55m
2026-07-10 QXE2060 FAI → ANC Jul 10, 12:55 UTCJul 10, 13:40 UTC45m
2026-07-10 QXE2277 ANC → FAI Jul 10, 07:10 UTCJul 10, 07:56 UTC46m
2026-07-10 QXE2277 ANC → FAI Jul 10, 07:10 UTCJul 10, 08:00 UTC50m
2026-07-10 QXE2130 LAX → SEA Jul 10, 02:35 UTCJul 10, 03:55 UTC1h 20m
2026-07-10 QXE2226 ANC → OTZ Jul 10, 00:10 UTCJul 10, 01:25 UTC1h 15m
2026-07-09 QXE2160 AKN → ANC Jul 9, 22:15 UTCJul 9, 22:51 UTC36m
2026-07-09 QXE2160 AKN → ANC Jul 9, 22:00 UTCJul 9, 22:50 UTC50m
2026-07-09 QXE2158 ANC → AKN Jul 9, 20:10 UTCJul 9, 21:00 UTC50m
2026-07-09 QXE2158 ANC → AKN Jul 9, 20:07 UTCJul 9, 20:51 UTC44m
2026-07-09 QXE2074 - Jul 9, 18:00 UTCJul 9, 19:15 UTC1h 15m
2026-07-09 QXE2073 SFO → LAX Jul 9, 15:35 UTCJul 9, 16:30 UTC55m
2026-07-09 QXE2073 SFO → LAX Jul 9, 15:35 UTCJul 9, 16:51 UTC1h 16m
2026-07-09 QXE2192 PDX → ANC Jul 9, 04:55 UTCJul 9, 08:25 UTC3h 30m
2026-07-09 QXE2056 SEA → SJC Jul 9, 00:50 UTCJul 9, 02:30 UTC1h 40m
2026-07-09 QXE2056 SEA → SJC Jul 9, 00:47 UTCJul 9, 02:30 UTC1h 43m
2026-07-08 QXE2056 SEA → SJC Jul 8, 21:45 UTCJul 8, 23:30 UTC1h 45m
2026-07-08 QXE2269 - Jul 8, 17:40 UTCJul 8, 20:15 UTC2h 35m
2026-07-08 QXE2268 - Jul 8, 14:15 UTCJul 8, 16:40 UTC2h 25m

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 1h ago.
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, QXE2090, QXE2340, QXE2007, QXE2509.