Apparatus

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sensors Mode-S transponder

A5E509

ICAO 24-bit transponder address · allocated to United States

Currently assigned to N4791E · CESSNA 172 Skyhawk · operated by MELBOURNE FLIGHT TRAINING LLC

Hex
A5E509
Octal
51362411
Decimal
10,872,073
Country
US
Tail
N4791E
Type
C172
No current signal · last broadcast 1d ago
Flights observed
8
Distinct callsigns
1
Country
US
Last broadcast
1d ago

Last known position

Most recent position reported by Mode-S A5E509.

Country allocation

The ICAO 24-bit address A5E509 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
N4791E - 8 2026-04-13

Recent flights last 8

DateFlightRouteTakeoffLandingDuration
2026-04-13 N4791E MLB → MLB Apr 13, 20:55 UTCApr 13, 22:05 UTC1h 10m
2026-04-13 N4791E - Apr 13, 19:10 UTCApr 13, 19:25 UTC15m
2026-04-13 N4791E - Apr 13, 18:10 UTCApr 13, 18:25 UTC15m
2026-04-13 N4791E - Apr 13, 15:05 UTCApr 13, 15:50 UTC45m
2026-04-13 N4791E - Apr 13, 12:20 UTCApr 13, 12:35 UTC15m
2026-04-13 N4791E - Apr 13, 11:55 UTCApr 13, 12:35 UTC40m
2026-04-13 N4791E - Apr 13, 11:40 UTCApr 13, 12:15 UTC35m
2026-04-12 N4791E - Apr 12, 17:30 UTCApr 12, 18:50 UTC1h 20m

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 N4791E page for operator, model, and routing details .

Mode-S A5E509 frequently asked

What is Mode-S code A5E509?
A5E509 is an ICAO 24-bit transponder address. Allocated to United States. Assigned to N4791E.
Where is Mode-S A5E509 registered?
Mode-S code A5E509 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 A5E509 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 A5E509, octal 51362411, decimal 10,872,073.
What flights does A5E509 operate?
Mode-S A5E509 has broadcast 1 distinct callsign, including N4791E.