sensors Mode-S transponder

505903

ICAO 24-bit transponder address

Hex
505903
Octal
24054403
Decimal
5,265,667
No current signal · last broadcast 3h ago
Flights observed
5
Distinct callsigns
1
Country
-
Last broadcast
3h ago

Last known position

Most recent position reported by Mode-S 505903.

Callsign history 1 distinct

Callsign Airline Flights Last seen
OMM769 - 5 2026-07-25

Recent flights last 5

DateFlightRouteTakeoffLandingDuration
2026-07-25 OMM769 - Jul 25, 15:40 UTCJul 25, 16:00 UTC20m
2026-07-25 OMM769 - Jul 25, 12:25 UTCJul 25, 12:45 UTC20m
2026-07-22 OMM769 - Jul 22, 16:40 UTCJul 22, 17:20 UTC40m
2026-07-17 OMM769 - Jul 17, 09:30 UTCJul 17, 10:10 UTC40m
2026-07-16 OMM769 - Jul 16, 11:50 UTCJul 16, 12:49 UTC1h 0m

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.

Mode-S 505903 frequently asked

What is Mode-S code 505903?
505903 is an ICAO 24-bit transponder address.
Is 505903 broadcasting right now?
No active broadcast right now. Last signal was 3h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 505903, octal 24054403, decimal 5,265,667.
What flights does 505903 operate?
Mode-S 505903 has broadcast 1 distinct callsign, including OMM769.