sensors Mode-S transponder

AD8857

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N971LA · CESSNA 408 SkyCourier · operated by TVPX AIRCRAFT SOLUTIONS INC TRUSTEE

Hex
AD8857
Octal
53304127
Decimal
11,372,631
Country
US
Tail
N971LA
Type
C408
No current signal · last broadcast 1d ago
Flights observed
5
Distinct callsigns
5
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S AD8857.

Country allocation

The ICAO 24-bit address AD8857 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
STT817 - 1 2026-04-13
STT813 - 1 2026-04-13
STT422 - 1 2026-04-13
STT416 - 1 2026-04-13
STT412 Air St. Thomas 1 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 STT817 - Apr 13, 22:55 UTCApr 13, 23:15 UTC20m
2026-04-13 STT416 - Apr 13, 22:00 UTCApr 13, 22:25 UTC25m
2026-04-13 STT813 - Apr 13, 21:00 UTCApr 13, 21:25 UTC25m
2026-04-13 STT412 HNL → LNY Apr 13, 20:05 UTCApr 13, 20:25 UTC20m
2026-04-13 STT422 - Apr 13, 02:00 UTCApr 13, 03:00 UTC1h 0m

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 N971LA page for operator, model, and routing details .

Mode-S AD8857 frequently asked

What is Mode-S code AD8857?
AD8857 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N971LA.
Where is Mode-S AD8857 registered?
Mode-S code AD8857 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 AD8857 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 AD8857, octal 53304127, decimal 11,372,631.
What flights does AD8857 operate?
Mode-S AD8857 has broadcast 5 distinct callsigns, including STT817, STT813, STT422, STT416, STT412.