sensors Mode-S transponder

A99221

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N7158S · ROBINSON R-22 Mariner · operated by HAWAII PACIFIC AVIATION INC

Hex
A99221
Octal
52311041
Decimal
11,112,993
Country
US
Tail
N7158S
Type
R22
Broadcasting now · callsign N7158S · 800 ft
Flights observed
5
Distinct callsigns
1
Country
US
Last broadcast
23h ago

Current position

A99221 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A99221 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
N7158S - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 N7158S - Apr 13, 23:25 UTCApr 13, 23:45 UTC20m
2026-04-13 N7158S - Apr 13, 21:20 UTCApr 13, 22:05 UTC45m
2026-04-13 N7158S - Apr 13, 19:50 UTCApr 13, 20:25 UTC35m
2026-04-13 N7158S - Apr 13, 19:35 UTCApr 13, 20:10 UTC35m
2026-04-13 N7158S - Apr 13, 17:45 UTCApr 13, 18:55 UTC1h 10m

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 N7158S page for operator, model, and routing details .

Mode-S A99221 frequently asked

What is Mode-S code A99221?
A99221 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N7158S.
Where is Mode-S A99221 registered?
Mode-S code A99221 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 A99221 broadcasting right now?
Yes. Mode-S A99221 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A99221, octal 52311041, decimal 11,112,993.
What flights does A99221 operate?
Mode-S A99221 has broadcast 1 distinct callsign, including N7158S.