sensors Mode-S transponder

A709A9

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N5523Q · CESSNA 172 Skyhawk · operated by DOLPHIN LEASING LLC

Hex
A709A9
Octal
51604651
Decimal
10,946,985
Country
US
Tail
N5523Q
Type
C172
Broadcasting now · callsign BPX250 · 1,225 ft
Flights observed
5
Distinct callsigns
1
Country
US
Last broadcast
23h ago

Current position

A709A9 is currently broadcasting. Map zoomed to live position.

Country allocation

The ICAO 24-bit address A709A9 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
BPX250 - 5 2026-04-13

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-04-13 BPX250 - Apr 13, 23:30 UTCApr 13, 23:40 UTC10m
2026-04-13 BPX250 - Apr 13, 22:40 UTCApr 13, 23:00 UTC20m
2026-04-13 BPX250 - Apr 13, 20:10 UTCApr 13, 20:25 UTC15m
2026-04-13 BPX250 - Apr 13, 11:55 UTCApr 13, 12:40 UTC45m
2026-04-13 BPX250 - Apr 13, 11:35 UTCApr 13, 12:05 UTC30m

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 N5523Q page for operator, model, and routing details .

Mode-S A709A9 frequently asked

What is Mode-S code A709A9?
A709A9 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N5523Q.
Where is Mode-S A709A9 registered?
Mode-S code A709A9 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 A709A9 broadcasting right now?
Yes. Mode-S A709A9 is currently airborne.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex A709A9, octal 51604651, decimal 10,946,985.
What flights does A709A9 operate?
Mode-S A709A9 has broadcast 1 distinct callsign, including BPX250.