sensors Mode-S transponder

A87CF9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N646QX · EMBRAER ERJ-170-200 (long wing) · operated by HORIZON AIR INDUSTRIES INC

Hex
A87CF9
Octal
52076371
Decimal
11,042,041
Country
US
Tail
N646QX
Type
E75L
No current signal · last broadcast 16h ago
Flights observed
8
Distinct callsigns
6
Country
US
Last broadcast
16h ago

Last known position

Most recent position reported by Mode-S A87CF9.

Country allocation

The ICAO 24-bit address A87CF9 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 6 distinct

Callsign Airline Flights Last seen
QXE2271 - 3 2026-04-13
QXE2444 Horizon Air 1 2026-04-13
QXE2364 Horizon Air 1 2026-04-14
QXE2351 - 1 2026-04-13
QXE2350 - 1 2026-04-12
QXE2276 - 1 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-14 QXE2364 SEA → PUW Apr 14, 06:10 UTCApr 14, 06:33 UTC23m
2026-04-13 QXE2444 SFO → LAX Apr 13, 21:10 UTCApr 13, 23:45 UTC2h 35m
2026-04-13 QXE2276 - Apr 13, 18:18 UTCApr 13, 19:37 UTC1h 19m
2026-04-13 QXE2271 - Apr 13, 16:15 UTCApr 13, 17:20 UTC1h 5m
2026-04-13 QXE2271 - Apr 13, 15:55 UTCApr 13, 17:20 UTC1h 25m
2026-04-13 QXE2271 - Apr 13, 15:47 UTCApr 13, 17:10 UTC1h 23m
2026-04-13 QXE2351 - Apr 13, 00:20 UTCApr 13, 01:35 UTC1h 15m
2026-04-12 QXE2350 - Apr 12, 17:20 UTCApr 12, 20:15 UTC2h 55m

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 N646QX page for operator, model, and routing details .

Mode-S A87CF9 frequently asked

What is Mode-S code A87CF9?
A87CF9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N646QX.
Where is Mode-S A87CF9 registered?
Mode-S code A87CF9 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 A87CF9 broadcasting right now?
No active broadcast right now. Last signal was 16h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A87CF9, octal 52076371, decimal 11,042,041.
What flights does A87CF9 operate?
Mode-S A87CF9 has broadcast 6 distinct callsigns, including QXE2271, QXE2444, QXE2364, QXE2351, QXE2350.