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
Broadcasting now · callsign QXE2286 · 2,125 ft
Flights observed
11
Distinct callsigns
7
Country
US
Last broadcast
17h ago

Current position

A8557A is currently broadcasting. Map zoomed to live position.

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 7 distinct

Callsign Airline Flights Last seen
QXE2346 - 3 2026-04-13
QXE2272 - 2 2026-04-14
QXE2263 Horizon Air 2 2026-04-13
QXE2227 - 1 2026-04-13
QXE2209 Horizon Air 1 2026-04-12
QXE2199 - 1 2026-04-13
QXE2119 - 1 2026-04-12

Recent flights last 11

DateFlightRouteTakeoffLandingDuration
2026-04-14 QXE2272 - Apr 14, 05:15 UTCApr 14, 05:40 UTC25m
2026-04-13 QXE2227 - Apr 13, 22:10 UTCApr 13, 23:45 UTC1h 35m
2026-04-13 QXE2346 - Apr 13, 19:50 UTCApr 13, 20:30 UTC40m
2026-04-13 QXE2346 - Apr 13, 19:40 UTCApr 13, 20:10 UTC30m
2026-04-13 QXE2346 - Apr 13, 17:46 UTCApr 13, 18:32 UTC46m
2026-04-13 QXE2263 SJC → PDX Apr 13, 15:50 UTCApr 13, 16:10 UTC20m
2026-04-13 QXE2263 SJC → PDX Apr 13, 14:52 UTCApr 13, 16:05 UTC1h 13m
2026-04-13 QXE2272 - Apr 13, 04:24 UTCApr 13, 05:47 UTC1h 23m
2026-04-13 QXE2199 - Apr 13, 00:55 UTCApr 13, 02:50 UTC1h 55m
2026-04-12 QXE2209 LAX → SJC Apr 12, 19:50 UTCApr 12, 20:39 UTC49m
2026-04-12 QXE2119 - Apr 12, 16:41 UTCApr 12, 18:06 UTC1h 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?
Yes. Mode-S A8557A is currently airborne.
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 7 distinct callsigns, including QXE2346, QXE2272, QXE2263, QXE2227, QXE2209.