sensors Mode-S transponder

4CA9A1

ICAO 24-bit transponder address · allocated to Ireland

Currently assigned to EI-RZB · BOEING 737 MAX 8

Hex
4CA9A1
Octal
23124641
Decimal
5,024,161
Country
IE
Tail
EI-RZB
Type
B38M
No current signal · last broadcast 11h ago
Flights observed
83
Distinct callsigns
20
Country
IE
Last broadcast
11h ago

Last known position

Most recent position reported by Mode-S 4CA9A1.

Country allocation

The ICAO 24-bit address 4CA9A1 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 20 distinct

Callsign Airline Flights Last seen
NOS1521 Neos 11 2026-05-25
NOS1520 Neos 7 2026-05-25
NOS4723 Neos 6 2026-04-30
NOS7929 Neos 5 2026-05-03
NOS3865 Neos 5 2026-05-27
NOS29HP Neos 5 2026-05-08
NOS7420 Neos 4 2026-05-25
NOS69SQ Neos 4 2026-05-04
NOS6023 - 3 2026-05-09
NOS89RJ Neos 2 2026-04-17
NOS8071 - 2 2026-05-29
NOS7421 Neos 2 2026-05-25
NOS7027 Neos 2 2026-05-24
NOS5091 Neos 2 2026-05-29
NOS5090 Neos 2 2026-05-29
NOS47YJ - 2 2026-05-23
NOS26AR - 2 2026-05-29
NOS1765 Neos 2 2026-04-27
NOS9154 Neos 1 2026-05-17
NOS9153 Neos 1 2026-05-14

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 NOS8071 - May 29, 16:20 UTCMay 29, 17:35 UTC1h 15m
2026-05-29 NOS5091 HAM → CTA May 29, 12:45 UTCMay 29, 14:55 UTC2h 10m
2026-05-29 NOS5090 AOI → HAM May 29, 09:35 UTCMay 29, 11:20 UTC1h 45m
2026-05-29 NOS26AR - May 29, 07:40 UTCMay 29, 08:15 UTC35m
2026-05-28 NOS7630 - May 28, 05:25 UTCMay 28, 13:50 UTC8h 25m
2026-05-27 NOS3865 BGY → BVC May 27, 19:15 UTCMay 27, 22:45 UTC3h 30m
2026-05-27 NOS3865 BGY → BVC May 27, 09:25 UTCMay 27, 13:00 UTC3h 35m
2026-05-25 NOS7421 IBZ → MXP May 25, 21:09 UTCMay 26, 02:24 UTC5h 15m
2026-05-25 NOS1520 VRN → DSS May 25, 14:15 UTCMay 25, 19:35 UTC5h 19m
2026-05-25 NOS1521 DSS → VRN May 25, 06:30 UTCMay 25, 11:45 UTC5h 15m
2026-05-25 NOS7420 BGY → DSS May 25, 04:25 UTCMay 25, 05:00 UTC35m
2026-05-24 NOS7420 BGY → DSS May 24, 23:30 UTCMay 24, 23:46 UTC16m
2026-05-24 NOS8027 - May 24, 16:55 UTCMay 24, 17:15 UTC20m
2026-05-24 NOS7027 RMF → VRN May 24, 06:30 UTCMay 24, 15:25 UTC8h 55m
2026-05-23 NOS47YJ - May 23, 09:45 UTCMay 23, 18:55 UTC9h 10m
2026-05-22 NOS8071 - May 22, 16:10 UTCMay 22, 17:10 UTC1h 0m
2026-05-22 NOS5091 HAM → CTA May 22, 12:50 UTCMay 22, 14:40 UTC1h 50m
2026-05-22 NOS5090 AOI → HAM May 22, 08:35 UTCMay 22, 11:05 UTC2h 30m
2026-05-22 NOS26AR - May 22, 05:35 UTCMay 22, 06:45 UTC1h 10m
2026-05-20 NOS3865 BGY → BVC May 20, 19:15 UTCMay 20, 23:05 UTC3h 50m
2026-05-20 NOS3865 BGY → BVC May 20, 09:15 UTCMay 20, 13:10 UTC3h 55m
2026-05-18 NOS7421 IBZ → MXP May 18, 20:40 UTCMay 19, 01:55 UTC5h 15m
2026-05-18 NOS1520 VRN → DSS May 18, 13:45 UTCMay 18, 19:05 UTC5h 19m
2026-05-18 NOS1521 DSS → VRN May 18, 06:35 UTCMay 18, 11:15 UTC4h 40m
2026-05-17 NOS7420 BGY → DSS May 17, 23:20 UTCMay 18, 04:51 UTC5h 31m
2026-05-17 NOS8154 - May 17, 15:25 UTCMay 17, 16:10 UTC45m
2026-05-17 NOS9154 MXP → NAP May 17, 12:40 UTCMay 17, 14:10 UTC1h 30m
2026-05-16 NOS8124 - May 16, 16:50 UTCMay 16, 17:50 UTC1h 0m
2026-05-16 NOS9124 - May 16, 15:05 UTCMay 16, 16:00 UTC55m
2026-05-16 NOS8123 - May 16, 11:46 UTCMay 16, 12:21 UTC35m
2026-05-14 NOS9153 NAP → MXP May 14, 08:00 UTCMay 14, 09:35 UTC1h 35m
2026-05-14 NOS8153 - May 14, 05:40 UTCMay 14, 06:25 UTC45m
2026-05-13 NOS3865 BGY → BVC May 13, 09:05 UTCMay 13, 22:35 UTC13h 30m
2026-05-11 NOS1520 VRN → DSS May 11, 17:10 UTCMay 12, 06:15 UTC13h 5m
2026-05-11 NOS1521 DSS → VRN May 11, 12:00 UTCMay 11, 14:20 UTC2h 20m
2026-05-11 NOS1521 DSS → VRN May 11, 09:25 UTCMay 11, 09:40 UTC15m
2026-05-10 NOS7420 BGY → DSS May 10, 23:25 UTCMay 11, 05:25 UTC6h 0m
2026-05-10 NOS8525 - May 10, 16:50 UTCMay 10, 17:05 UTC15m
2026-05-10 NOS7027 RMF → VRN May 10, 06:25 UTCMay 10, 15:29 UTC9h 5m
2026-05-09 NOS6023 - May 9, 09:25 UTCMay 9, 18:15 UTC8h 50m
2026-05-08 NOS29HP RMF → VRN May 8, 05:44 UTCMay 8, 14:30 UTC8h 45m
2026-05-07 NOS42VW - May 7, 17:15 UTCMay 8, 02:14 UTC9h 0m
2026-05-05 NOS1521 DSS → VRN May 5, 03:55 UTCMay 5, 08:45 UTC4h 50m
2026-05-04 NOS1520 VRN → DSS May 4, 20:15 UTCMay 5, 02:30 UTC6h 15m
2026-05-04 NOS69SQ VRN → FUE May 4, 06:35 UTCMay 4, 15:20 UTC8h 45m
2026-05-03 NOS7929 SSH → VRN May 3, 06:30 UTCMay 3, 16:05 UTC9h 35m
2026-05-02 NOS6023 - May 2, 06:20 UTCMay 2, 15:10 UTC8h 50m
2026-05-01 NOS29HP RMF → VRN May 1, 05:30 UTCMay 1, 14:25 UTC8h 55m
2026-04-30 NOS4723 SID → VRN Apr 30, 09:10 UTCApr 30, 22:35 UTC13h 25m
2026-04-28 NOS1521 DSS → VRN Apr 28, 06:40 UTCApr 28, 08:30 UTC1h 50m

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-RZB page for operator, model, and routing details .

Mode-S 4CA9A1 frequently asked

What is Mode-S code 4CA9A1?
4CA9A1 is an ICAO 24-bit transponder address. Allocated to Ireland. Assigned to EI-RZB.
Where is Mode-S 4CA9A1 registered?
Mode-S code 4CA9A1 is allocated to Ireland (IE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4CA9A1 broadcasting right now?
No active broadcast right now. Last signal was 11h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4CA9A1, octal 23124641, decimal 5,024,161.
What flights does 4CA9A1 operate?
Mode-S 4CA9A1 has broadcast 20 distinct callsigns, including NOS1521, NOS1520, NOS4723, NOS7929, NOS3865.