sensors Mode-S transponder

A9E91A

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N738DM · CESSNA 172 Skyhawk · operated by BUIQUI AEROSPACE CORP

Hex
A9E91A
Octal
52364432
Decimal
11,135,258
Country
US
Tail
N738DM
Type
C172
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 A9E91A.

Country allocation

The ICAO 24-bit address A9E91A 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
N738DM - 2 2026-04-13

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-13 N738DM - Apr 13, 21:30 UTCApr 13, 23:30 UTC2h 0m
2026-04-13 N738DM - Apr 13, 16:40 UTCApr 13, 17:35 UTC55m

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 N738DM page for operator, model, and routing details .

Mode-S A9E91A frequently asked

What is Mode-S code A9E91A?
A9E91A is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N738DM.
Where is Mode-S A9E91A registered?
Mode-S code A9E91A 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 A9E91A 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 A9E91A, octal 52364432, decimal 11,135,258.
What flights does A9E91A operate?
Mode-S A9E91A has broadcast 1 distinct callsign, including N738DM.