sensors Mode-S transponder

A0E5FE

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N157UM · AIRBUS HELICOPTERS EC-155 · operated by REGENTS OF THE UNIVERSITY OF MICHIGAN

Hex
A0E5FE
Octal
50162776
Decimal
10,544,638
Country
US
Tail
N157UM
Type
EC55
No current signal · last broadcast 1d ago
Flights observed
2
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A0E5FE.

Country allocation

The ICAO 24-bit address A0E5FE 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
N157UM - 2 2026-04-13

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-13 N157UM - Apr 13, 18:10 UTCApr 13, 19:00 UTC50m
2026-04-12 N157UM - Apr 12, 17:25 UTCApr 12, 17:45 UTC20m

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 N157UM page for operator, model, and routing details .

Mode-S A0E5FE frequently asked

What is Mode-S code A0E5FE?
A0E5FE is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N157UM.
Where is Mode-S A0E5FE registered?
Mode-S code A0E5FE 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 A0E5FE 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 A0E5FE, octal 50162776, decimal 10,544,638.
What flights does A0E5FE operate?
Mode-S A0E5FE has broadcast 1 distinct callsign, including N157UM.