Apparatus

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sensors Mode-S transponder

A9A7FA

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N721HH · ROBINSON R-22 Mariner · operated by HAWAII PACIFIC AVIATION INC

Hex
A9A7FA
Octal
52323772
Decimal
11,118,586
Country
US
Tail
N721HH
Type
R22
No current signal · last broadcast 1d ago
Flights observed
7
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A9A7FA.

Country allocation

The ICAO 24-bit address A9A7FA 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
N721HH - 7 2026-04-13

Recent flights last 7

DateFlightRouteTakeoffLandingDuration
2026-04-13 N721HH - Apr 13, 23:25 UTCApr 13, 23:40 UTC15m
2026-04-13 N721HH KOA → KOA Apr 13, 21:30 UTCApr 13, 22:10 UTC40m
2026-04-13 N721HH - Apr 13, 19:50 UTCApr 13, 20:10 UTC20m
2026-04-13 N721HH KOA → KOA Apr 13, 19:40 UTCApr 13, 20:10 UTC30m
2026-04-13 N721HH KOA → KOA Apr 13, 17:45 UTCApr 13, 18:25 UTC40m
2026-04-12 N721HH KOA → KOA Apr 12, 19:35 UTCApr 12, 20:10 UTC35m
2026-04-12 N721HH KOA → KOA Apr 12, 17:45 UTCApr 12, 18:30 UTC45m

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 N721HH page for operator, model, and routing details .

Mode-S A9A7FA frequently asked

What is Mode-S code A9A7FA?
A9A7FA is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N721HH.
Where is Mode-S A9A7FA registered?
Mode-S code A9A7FA 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 A9A7FA 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 A9A7FA, octal 52323772, decimal 11,118,586.
What flights does A9A7FA operate?
Mode-S A9A7FA has broadcast 1 distinct callsign, including N721HH.