sensors Mode-S transponder

AA3B99

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N759BH · AIRBUS HELICOPTERS EC-145 · operated by AIR METHODS LLC

Hex
AA3B99
Octal
52435631
Decimal
11,156,377
Country
US
Tail
N759BH
Type
EC45
No current signal · last broadcast 2d ago
Flights observed
2
Distinct callsigns
1
Country
US
Last broadcast
2d ago

Last known position

Most recent position reported by Mode-S AA3B99.

Country allocation

The ICAO 24-bit address AA3B99 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
N759BH - 2 2026-04-12

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-12 N759BH - Apr 12, 19:30 UTCApr 12, 19:45 UTC15m
2026-04-12 N759BH - Apr 12, 18:25 UTCApr 12, 18:35 UTC10m

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 N759BH page for operator, model, and routing details .

Mode-S AA3B99 frequently asked

What is Mode-S code AA3B99?
AA3B99 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N759BH.
Where is Mode-S AA3B99 registered?
Mode-S code AA3B99 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 AA3B99 broadcasting right now?
No active broadcast right now. Last signal was 2d ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex AA3B99, octal 52435631, decimal 11,156,377.
What flights does AA3B99 operate?
Mode-S AA3B99 has broadcast 1 distinct callsign, including N759BH.