Apparatus

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sensors Mode-S transponder

4CAF00

ICAO 24-bit transponder address · allocated to Ireland

Currently assigned to EI-HRF · BOEING 737-800

Hex
4CAF00
Octal
23127400
Decimal
5,025,536
Country
IE
Tail
EI-HRF
Type
B738
No current signal · last broadcast Jul 26, 19:45 UTC
Flights observed
85
Distinct callsigns
14
Country
IE
Last broadcast
Jul 26, 19:45 UTC

Last known position

Most recent position reported by Mode-S 4CAF00.

Country allocation

The ICAO 24-bit address 4CAF00 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 14 distinct

Callsign Airline Flights Last seen
CGS4421 - 24 2026-07-26
CGS4418 - 23 2026-07-24
CGS4420 Centre of Applied Geodynamica 12 2026-07-23
CGS4419 - 9 2026-07-24
CGS801 Centre of Applied Geodynamica 4 2026-06-20
CGS808 Centre of Applied Geodynamica 2 2026-06-26
CGS807 - 2 2026-06-25
CGS802 - 2 2026-06-21
CGS707 - 2 2026-05-22
CGS708 - 1 2026-05-22
CGS706 - 1 2026-05-23
CGS705 - 1 2026-05-21
CGS135 - 1 2026-07-01
CGS134 - 1 2026-07-01

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 CGS4421 - Jul 26, 19:20 UTCJul 26, 19:45 UTC25m
2026-07-24 CGS4419 - Jul 24, 10:20 UTCJul 24, 10:50 UTC30m
2026-07-24 CGS4418 - Jul 24, 00:30 UTCJul 24, 01:00 UTC30m
2026-07-23 CGS4421 - Jul 23, 22:35 UTCJul 23, 23:00 UTC25m
2026-07-23 CGS4420 DWC → NBO Jul 23, 15:50 UTCJul 23, 16:00 UTC10m
2026-07-23 CGS4420 DWC → NBO Jul 23, 11:25 UTCJul 23, 11:55 UTC30m
2026-07-21 CGS4418 - Jul 21, 23:25 UTCJul 21, 23:50 UTC25m
2026-07-21 CGS4421 - Jul 21, 21:15 UTCJul 21, 21:45 UTC30m
2026-07-21 CGS4420 DWC → NBO Jul 21, 10:55 UTCJul 21, 11:30 UTC35m
2026-07-21 CGS4419 - Jul 21, 06:45 UTCJul 21, 07:05 UTC20m
2026-07-20 CGS4418 - Jul 20, 20:30 UTCJul 20, 20:55 UTC25m
2026-07-19 CGS4421 - Jul 19, 20:00 UTCJul 19, 20:30 UTC30m
2026-07-14 CGS4419 - Jul 14, 07:10 UTCJul 14, 07:40 UTC30m
2026-07-13 CGS4418 - Jul 13, 20:45 UTCJul 13, 21:10 UTC25m
2026-07-12 CGS4421 - Jul 12, 19:01 UTCJul 12, 19:30 UTC30m
2026-07-12 CGS4420 - Jul 12, 08:40 UTCJul 12, 09:15 UTC35m
2026-07-07 CGS4419 - Jul 7, 06:40 UTCJul 7, 07:05 UTC25m
2026-07-06 CGS4418 - Jul 6, 20:50 UTCJul 6, 21:15 UTC25m
2026-07-05 CGS4421 - Jul 5, 18:40 UTCJul 5, 19:15 UTC35m
2026-07-05 CGS4420 - Jul 5, 08:25 UTCJul 5, 08:55 UTC30m
2026-07-01 CGS135 - Jul 1, 15:50 UTCJul 1, 16:45 UTC55m
2026-07-01 CGS134 - Jul 1, 13:15 UTCJul 1, 13:35 UTC20m
2026-06-30 CGS4419 - Jun 30, 23:40 UTCJul 1, 10:35 UTC10h 55m
2026-06-30 CGS4420 - Jun 30, 11:25 UTCJun 30, 21:45 UTC10h 20m
2026-06-29 CGS4419 - Jun 29, 20:19 UTCJun 30, 06:50 UTC10h 31m
2026-06-29 CGS4421 - Jun 29, 00:00 UTCJun 29, 00:29 UTC30m
2026-06-28 CGS4420 - Jun 28, 10:39 UTCJun 28, 11:14 UTC35m
2026-06-26 CGS808 NBO → DWC Jun 26, 11:20 UTCJun 26, 11:45 UTC25m
2026-06-25 CGS807 - Jun 25, 11:19 UTCJun 25, 11:54 UTC35m
2026-06-24 CGS4419 - Jun 24, 09:39 UTCJun 24, 09:59 UTC20m
2026-06-23 CGS4418 - Jun 23, 23:50 UTCJun 24, 00:09 UTC20m
2026-06-23 CGS4421 - Jun 23, 20:54 UTCJun 23, 21:29 UTC35m
2026-06-23 CGS4420 - Jun 23, 10:24 UTCJun 23, 10:59 UTC35m
2026-06-22 CGS808 NBO → DWC Jun 22, 21:54 UTCJun 22, 22:05 UTC10m
2026-06-21 CGS807 - Jun 21, 11:15 UTCJun 21, 11:34 UTC20m
2026-06-21 CGS802 - Jun 21, 06:19 UTCJun 21, 06:50 UTC30m
2026-06-20 CGS801 LST → FLS Jun 20, 13:34 UTCJun 20, 13:49 UTC15m
2026-06-20 CGS801 LST → FLS Jun 20, 09:05 UTCJun 20, 09:29 UTC25m
2026-06-19 CGS4419 - Jun 19, 11:30 UTCJun 19, 11:45 UTC15m
2026-06-19 CGS4418 - Jun 19, 00:59 UTCJun 19, 01:24 UTC25m
2026-06-18 CGS4421 - Jun 18, 21:55 UTCJun 18, 22:25 UTC30m
2026-06-18 CGS4420 DWC → NBO Jun 18, 12:15 UTCJun 18, 12:35 UTC20m
2026-06-16 CGS4418 - Jun 16, 00:29 UTCJun 16, 01:00 UTC30m
2026-06-15 CGS4421 - Jun 15, 21:35 UTCJun 15, 22:10 UTC35m
2026-06-14 CGS4420 DWC → NBO Jun 14, 08:25 UTCJun 14, 08:45 UTC20m
2026-06-10 CGS4419 - Jun 10, 11:15 UTCJun 10, 11:30 UTC15m
2026-06-10 CGS4418 - Jun 10, 01:00 UTCJun 10, 01:25 UTC25m
2026-06-09 CGS4421 - Jun 9, 20:40 UTCJun 9, 21:15 UTC35m
2026-06-07 CGS802 - Jun 7, 23:05 UTCJun 7, 23:30 UTC25m
2026-06-05 CGS4418 - Jun 5, 00:30 UTCJun 5, 00:50 UTC20m

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

Mode-S 4CAF00 frequently asked

What is Mode-S code 4CAF00?
4CAF00 is an ICAO 24-bit transponder address. Allocated to Ireland. Assigned to EI-HRF.
Where is Mode-S 4CAF00 registered?
Mode-S code 4CAF00 is allocated to Ireland (IE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4CAF00 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 19:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4CAF00, octal 23127400, decimal 5,025,536.
What flights does 4CAF00 operate?
Mode-S 4CAF00 has broadcast 14 distinct callsigns, including CGS4421, CGS4418, CGS4420, CGS4419, CGS801.