sensors Mode-S transponder

A4E1D2

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N4131T · PIPER PA-28-140/150/160/180 · operated by SKYWEST LEASING INC

Hex
A4E1D2
Octal
51160722
Decimal
10,805,714
Country
US
Tail
N4131T
Type
P28A
No current signal · last broadcast 1d ago
Flights observed
5
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A4E1D2.

Country allocation

The ICAO 24-bit address A4E1D2 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
ASI283 - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 ASI283 - Apr 13, 19:50 UTCApr 13, 20:20 UTC30m
2026-04-13 ASI283 - Apr 13, 18:45 UTCApr 13, 20:10 UTC1h 25m
2026-04-13 ASI283 - Apr 13, 17:35 UTCApr 13, 18:15 UTC40m
2026-04-13 ASI283 DVT → DVT Apr 13, 14:10 UTCApr 13, 15:40 UTC1h 30m
2026-04-13 ASI283 DVT → DVT Apr 13, 00:20 UTCApr 13, 02:00 UTC1h 40m

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 N4131T page for operator, model, and routing details .

Mode-S A4E1D2 frequently asked

What is Mode-S code A4E1D2?
A4E1D2 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N4131T.
Where is Mode-S A4E1D2 registered?
Mode-S code A4E1D2 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 A4E1D2 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 A4E1D2, octal 51160722, decimal 10,805,714.
What flights does A4E1D2 operate?
Mode-S A4E1D2 has broadcast 1 distinct callsign, including ASI283.