sensors Mode-S transponder

A08FD1

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N135X · LEGEND · operated by RETRO THIS LLC

Hex
A08FD1
Octal
50107721
Decimal
10,522,577
Country
US
Tail
N135X
No current signal · last broadcast Jul 3, 15:45 UTC
Flights observed
5
Distinct callsigns
1
Country
US
Last broadcast
Jul 3, 15:45 UTC

Last known position

Most recent position reported by Mode-S A08FD1.

Country allocation

The ICAO 24-bit address A08FD1 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 1 distinct

Callsign Airline Flights Last seen
N135X - 5 2026-07-03

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-07-03 N135X - Jul 3, 15:00 UTCJul 3, 15:45 UTC45m
2026-07-02 N135X - Jul 2, 19:35 UTCJul 2, 19:45 UTC10m
2026-07-02 N135X - Jul 2, 17:40 UTCJul 2, 17:50 UTC10m
2026-07-02 N135X - Jul 2, 16:30 UTCJul 2, 16:45 UTC15m
2026-07-01 N135X - Jul 1, 22:05 UTCJul 1, 22:30 UTC25m

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 N135X page for operator, model, and routing details .

Mode-S A08FD1 frequently asked

What is Mode-S code A08FD1?
A08FD1 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N135X.
Where is Mode-S A08FD1 registered?
Mode-S code A08FD1 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 A08FD1 broadcasting right now?
No active broadcast right now. Last signal was Jul 3, 15:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A08FD1, octal 50107721, decimal 10,522,577.
What flights does A08FD1 operate?
Mode-S A08FD1 has broadcast 1 distinct callsign, including N135X.