sensors Mode-S transponder

A8D71C

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N669QX · operated by HORIZON AIR INDUSTRIES INC

Hex
A8D71C
Octal
52153434
Decimal
11,065,116
Country
US
Tail
N669QX
Type
E75L
No current signal · last broadcast 1d ago
Flights observed
7
Distinct callsigns
5
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A8D71C.

Country allocation

The ICAO 24-bit address A8D71C 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 5 distinct

Callsign Airline Flights Last seen
QXE2044 - 2 2026-04-12
QXE2008 - 2 2026-04-13
QXE9987 - 1 2026-04-13
QXE2222 - 1 2026-04-13
QXE2072 - 1 2026-04-12

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 QXE9987 - Apr 13, 19:52 UTCApr 13, 21:39 UTC1h 47m
2026-04-13 QXE2008 - Apr 13, 03:55 UTCApr 13, 04:15 UTC20m
2026-04-13 QXE2008 - Apr 13, 03:35 UTCApr 13, 04:15 UTC40m
2026-04-13 QXE2222 - Apr 13, 00:32 UTCApr 13, 01:42 UTC1h 10m
2026-04-12 QXE2072 - Apr 12, 20:10 UTCApr 12, 21:12 UTC1h 2m
2026-04-12 QXE2044 - Apr 12, 18:01 UTCApr 12, 19:05 UTC1h 4m
2026-04-12 QXE2044 - Apr 12, 17:50 UTCApr 12, 18:56 UTC1h 6m

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 N669QX page for operator, model, and routing details .

Mode-S A8D71C frequently asked

What is Mode-S code A8D71C?
A8D71C is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N669QX.
Where is Mode-S A8D71C registered?
Mode-S code A8D71C 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 A8D71C broadcasting right now?
No active broadcast right now. Last signal was 1d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A8D71C, octal 52153434, decimal 11,065,116.
What flights does A8D71C operate?
Mode-S A8D71C has broadcast 5 distinct callsigns, including QXE2044, QXE2008, QXE9987, QXE2222, QXE2072.