sensors Mode-S transponder

A5EC55

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N481AE · BELL 407 · operated by AIR EVAC EMS INC

Hex
A5EC55
Octal
51366125
Decimal
10,873,941
Country
US
Tail
N481AE
Type
B407
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 A5EC55.

Country allocation

The ICAO 24-bit address A5EC55 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
N481AE - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 N481AE - Apr 13, 22:55 UTCApr 13, 23:40 UTC45m
2026-04-13 N481AE - Apr 13, 18:55 UTCApr 13, 19:40 UTC45m
2026-04-13 N481AE - Apr 13, 16:35 UTCApr 13, 17:45 UTC1h 10m
2026-04-13 N481AE - Apr 13, 04:30 UTCApr 13, 05:00 UTC30m
2026-04-13 N481AE - Apr 13, 03:00 UTCApr 13, 03:40 UTC40m

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 N481AE page for operator, model, and routing details .

Mode-S A5EC55 frequently asked

What is Mode-S code A5EC55?
A5EC55 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N481AE.
Where is Mode-S A5EC55 registered?
Mode-S code A5EC55 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 A5EC55 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 A5EC55, octal 51366125, decimal 10,873,941.
What flights does A5EC55 operate?
Mode-S A5EC55 has broadcast 1 distinct callsign, including N481AE.