sensors Mode-S transponder

4CAC36

ICAO 24-bit transponder address · allocated to Ireland

Currently assigned to EI-RZD · BOEING 737 MAX 8

Hex
4CAC36
Octal
23126066
Decimal
5,024,822
Country
IE
Tail
EI-RZD
Type
B38M
No current signal · last broadcast 14h ago
Flights observed
2
Distinct callsigns
2
Country
IE
Last broadcast
14h ago

Last known position

Most recent position reported by Mode-S 4CAC36.

Country allocation

The ICAO 24-bit address 4CAC36 falls within the block assigned to Ireland (IE) by ICAO Annex 10, Volume III. Every aircraft registered in Ireland 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 2 distinct

Callsign Airline Flights Last seen
NOS7903 - 1 2026-04-12
NOS69XA Neos 1 2026-04-14

Recent flights last 2

DateFlightRouteTakeoffLandingDuration
2026-04-14 NOS69XA KEF → ALC Apr 14, 09:10 UTCApr 14, 11:05 UTC1h 55m
2026-04-12 NOS7903 - Apr 12, 17:25 UTCApr 12, 20:05 UTC2h 40m

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 EI-RZD page for operator, model, and routing details .

Mode-S 4CAC36 frequently asked

What is Mode-S code 4CAC36?
4CAC36 is an ICAO 24-bit transponder address. Allocated to Ireland. Assigned to EI-RZD.
Where is Mode-S 4CAC36 registered?
Mode-S code 4CAC36 is allocated to Ireland (IE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4CAC36 broadcasting right now?
No active broadcast right now. Last signal was 14h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4CAC36, octal 23126066, decimal 5,024,822.
What flights does 4CAC36 operate?
Mode-S 4CAC36 has broadcast 2 distinct callsigns, including NOS7903, NOS69XA.