sensors Mode-S transponder

A54D1D

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N4401E · PIPER PA-28-140/150/160/180 · operated by CAE OXFORD AVIATION ACADEMY PHOENIX INC

Hex
A54D1D
Octal
51246435
Decimal
10,833,181
Country
US
Tail
N4401E
Type
P28A
No current signal · last broadcast 1d ago
Flights observed
6
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A54D1D.

Country allocation

The ICAO 24-bit address A54D1D 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
OXF2880 - 6 2026-04-13

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-13 OXF2880 - Apr 13, 22:10 UTCApr 13, 23:40 UTC1h 30m
2026-04-13 OXF2880 - Apr 13, 17:40 UTCApr 13, 18:40 UTC1h 0m
2026-04-13 OXF2880 - Apr 13, 16:35 UTCApr 13, 16:55 UTC20m
2026-04-13 OXF2880 - Apr 13, 13:55 UTCApr 13, 15:35 UTC1h 40m
2026-04-13 OXF2880 - Apr 13, 03:55 UTCApr 13, 04:10 UTC15m
2026-04-13 OXF2880 MSC → MSC Apr 13, 02:35 UTCApr 13, 04:10 UTC1h 35m

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 N4401E page for operator, model, and routing details .

Mode-S A54D1D frequently asked

What is Mode-S code A54D1D?
A54D1D is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N4401E.
Where is Mode-S A54D1D registered?
Mode-S code A54D1D 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 A54D1D 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 A54D1D, octal 51246435, decimal 10,833,181.
What flights does A54D1D operate?
Mode-S A54D1D has broadcast 1 distinct callsign, including OXF2880.