sensors Mode-S transponder

504E81

ICAO 24-bit transponder address · allocated to Moldova

Currently assigned to ER-00011 · AIRBUS A-320

Hex
504E81
Octal
24047201
Decimal
5,262,977
Country
MD
Tail
ER-00011
Type
A320
No current signal · last broadcast 12h ago
Flights observed
6
Distinct callsigns
4
Country
MD
Last broadcast
12h ago

Last known position

Most recent position reported by Mode-S 504E81.

Country allocation

The ICAO 24-bit address 504E81 falls within the block assigned to Moldova (MD) by ICAO Annex 10, Volume III. Every aircraft registered in Moldova 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 4 distinct

Callsign Airline Flights Last seen
FIE533 - 2 2026-04-14
FIA6343 - 2 2026-04-13
FIA6344 - 1 2026-04-13
FIA5511 - 1 2026-04-14

Recent flights last 6

DateFlightRouteTakeoffLandingDuration
2026-04-14 FIA5511 - Apr 14, 09:20 UTCApr 14, 11:05 UTC1h 45m
2026-04-14 FIE533 - Apr 14, 05:15 UTCApr 14, 05:25 UTC10m
2026-04-13 FIA6344 - Apr 13, 12:30 UTCApr 13, 15:15 UTC2h 45m
2026-04-13 FIA6343 - Apr 13, 08:20 UTCApr 13, 10:30 UTC2h 10m
2026-04-13 FIA6343 - Apr 13, 08:10 UTCApr 13, 10:30 UTC2h 20m
2026-04-13 FIE533 - Apr 13, 04:35 UTCApr 13, 05:20 UTC45m

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 ER-00011 page for operator, model, and routing details .

Mode-S 504E81 frequently asked

What is Mode-S code 504E81?
504E81 is an ICAO 24-bit transponder address. Allocated to Moldova. Assigned to ER-00011.
Where is Mode-S 504E81 registered?
Mode-S code 504E81 is allocated to Moldova (MD). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 504E81 broadcasting right now?
No active broadcast right now. Last signal was 12h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 504E81, octal 24047201, decimal 5,262,977.
What flights does 504E81 operate?
Mode-S 504E81 has broadcast 4 distinct callsigns, including FIE533, FIA6343, FIA6344, FIA5511.