Apparatus

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sensors Mode-S transponder

A22B91

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N239ST · PIPER PA-32R-300/301/301T · operated by OUTER BANKS BOIL CO AVIATION LLC

Hex
A22B91
Octal
50425621
Decimal
10,627,985
Country
US
Tail
N239ST
Type
P32R
No current signal · last broadcast 15h ago
Flights observed
10
Distinct callsigns
1
Country
US
Last broadcast
15h ago

Last known position

Most recent position reported by Mode-S A22B91.

Country allocation

The ICAO 24-bit address A22B91 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
N239ST - 10 2026-04-14

Recent flights last 10

DateFlightRouteTakeoffLandingDuration
2026-04-14 N239ST - Apr 14, 09:30 UTCApr 14, 11:05 UTC1h 35m
2026-04-13 N239ST - Apr 13, 16:15 UTCApr 13, 16:40 UTC25m
2026-04-13 N239ST - Apr 13, 15:50 UTCApr 13, 16:40 UTC50m
2026-04-13 N239ST - Apr 13, 15:25 UTCApr 13, 16:15 UTC50m
2026-04-13 N239ST - Apr 13, 13:20 UTCApr 13, 13:45 UTC25m
2026-04-13 N239ST TPA → PIE Apr 13, 11:55 UTCApr 13, 12:05 UTC10m
2026-04-13 N239ST - Apr 13, 11:40 UTCApr 13, 12:05 UTC25m
2026-04-13 N239ST - Apr 13, 00:55 UTCApr 13, 01:45 UTC50m
2026-04-12 N239ST - Apr 12, 23:55 UTCApr 13, 00:05 UTC10m
2026-04-12 N239ST - Apr 12, 17:15 UTCApr 12, 17:40 UTC25m

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 N239ST page for operator, model, and routing details .

Mode-S A22B91 frequently asked

What is Mode-S code A22B91?
A22B91 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N239ST.
Where is Mode-S A22B91 registered?
Mode-S code A22B91 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 A22B91 broadcasting right now?
No active broadcast right now. Last signal was 15h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A22B91, octal 50425621, decimal 10,627,985.
What flights does A22B91 operate?
Mode-S A22B91 has broadcast 1 distinct callsign, including N239ST.