Apparatus

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sensors Mode-S transponder

4CAD51

ICAO 24-bit transponder address · allocated to Ireland

Currently assigned to EI-HDK · ATR-72-600

Hex
4CAD51
Octal
23126521
Decimal
5,025,105
Country
IE
Tail
EI-HDK
Type
AT76
No current signal · last broadcast 4h ago
Flights observed
376
Distinct callsigns
20
Country
IE
Last broadcast
4h ago

Last known position

Most recent position reported by Mode-S 4CAD51.

Country allocation

The ICAO 24-bit address 4CAD51 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
EAI93D Elite Air 11 2026-05-24
EAI09U Elite Air 11 2026-05-23
EAI95C Elite Air 10 2026-05-24
EAI8C Elite Air 10 2026-05-23
EAI92B Elite Air 9 2026-05-24
EAI94S Elite Air 8 2026-05-24
EAI73N Elite Air 8 2026-05-29
EAI69M Elite Air 8 2026-05-26
EAI42A Elite Air 8 2026-05-24
EAI3RG Elite Air 8 2026-05-25
EAI38D Elite Air 8 2026-05-26
EAI33S Elite Air 8 2026-05-28
EAI32V Elite Air 8 2026-05-28
EAI31Q Elite Air 8 2026-05-28
EAI17W Elite Air 8 2026-05-28
EAI84LP Elite Air 7 2026-05-25
EAI81A Elite Air 7 2026-05-25
EAI51C Elite Air 7 2026-05-03
EAI50E Elite Air 7 2026-05-03
EAI34N Elite Air 7 2026-05-24

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-05-29 EAI46Z LPL → DUB May 29, 20:50 UTCMay 29, 21:25 UTC35m
2026-05-29 EAI36W DUB → LPL May 29, 19:20 UTCMay 29, 20:00 UTC40m
2026-05-29 EAI2A SOU → DUB May 29, 17:15 UTCMay 29, 18:30 UTC1h 15m
2026-05-29 EAI4HS DUB → SOU May 29, 15:10 UTCMay 29, 16:25 UTC1h 15m
2026-05-29 EAI65Y BHX → DUB May 29, 12:35 UTCMay 29, 13:35 UTC1h 0m
2026-05-29 EAI64B DUB → BHX May 29, 10:35 UTCMay 29, 11:30 UTC55m
2026-05-29 EAI37E NCL → DUB May 29, 08:45 UTCMay 29, 09:45 UTC1h 0m
2026-05-29 EAI73N DUB → DUB May 29, 06:55 UTCMay 29, 07:45 UTC50m
2026-05-28 EAI31Q EXT → DUB May 28, 20:45 UTCMay 28, 21:45 UTC1h 0m
2026-05-28 EAI33S DUB → EXT May 28, 19:00 UTCMay 28, 20:05 UTC1h 5m
2026-05-28 EAI57K EDI → DUB May 28, 16:55 UTCMay 28, 18:10 UTC1h 15m
2026-05-28 EAI6RC DUB → GLA May 28, 15:10 UTCMay 28, 16:00 UTC50m
2026-05-28 EAI13U IOM → DUB May 28, 13:25 UTCMay 28, 14:00 UTC35m
2026-05-28 EAI12B DUB → IOM May 28, 12:05 UTCMay 28, 12:25 UTC20m
2026-05-28 EAI17W MAN → DUB May 28, 09:30 UTCMay 28, 10:25 UTC55m
2026-05-28 EAI32V DUB → MAN May 28, 07:25 UTCMay 28, 08:10 UTC45m
2026-05-27 EAI75B BHX → DUB May 27, 18:20 UTCMay 27, 19:15 UTC55m
2026-05-27 EAI74G DUB → BHX May 27, 16:30 UTCMay 27, 17:25 UTC55m
2026-05-27 EAI85Y BRS → BRS May 27, 14:20 UTCMay 27, 15:20 UTC1h 0m
2026-05-27 EAI84U DUB → BRS May 27, 12:45 UTCMay 27, 13:40 UTC55m
2026-05-27 EAI73N DUB → DUB May 27, 08:55 UTCMay 27, 10:00 UTC1h 5m
2026-05-27 EAI73N DUB → DUB May 27, 07:15 UTCMay 27, 08:00 UTC45m
2026-05-26 EAI59L EDI → DUB May 26, 20:05 UTCMay 26, 21:04 UTC1h 0m
2026-05-26 EAI58Z DUB → EDI May 26, 18:34 UTCMay 26, 19:25 UTC50m
2026-05-26 EAI25LG GLA → DUB May 26, 16:40 UTCMay 26, 17:35 UTC55m
2026-05-26 EAI24CE DUB → GLA May 26, 13:54 UTCMay 26, 14:45 UTC50m
2026-05-26 EAI38D MAN → DUB May 26, 11:50 UTCMay 26, 12:40 UTC50m
2026-05-26 EAI69M DUB → MAN May 26, 10:10 UTCMay 26, 10:54 UTC45m
2026-05-26 EAI91M LBA → LBA May 26, 07:55 UTCMay 26, 08:54 UTC1h 0m
2026-05-26 EAI9L DUB → LBA May 26, 06:20 UTCMay 26, 07:05 UTC45m
2026-05-25 EAI3RG EDI → DUB May 25, 18:50 UTCMay 25, 19:50 UTC59m
2026-05-25 EAI35C DUB → EDI May 25, 17:10 UTCMay 25, 18:05 UTC55m
2026-05-25 EAI25LG GLA → DUB May 25, 15:15 UTCMay 25, 16:10 UTC55m
2026-05-25 EAI24CE DUB → GLA May 25, 13:45 UTCMay 25, 14:35 UTC50m
2026-05-25 EAI81A BRS → DUB May 25, 11:40 UTCMay 25, 12:40 UTC1h 0m
2026-05-25 EAI4RA ORK → BRS May 25, 09:45 UTCMay 25, 10:50 UTC1h 5m
2026-05-25 EAI84LP BRS → BRS May 25, 07:50 UTCMay 25, 09:00 UTC1h 10m
2026-05-25 EAI8BR DUB → BRS May 25, 06:05 UTCMay 25, 07:00 UTC55m
2026-05-24 EAI95C LBA → DUB May 24, 19:10 UTCMay 24, 20:00 UTC50m
2026-05-24 EAI94S DUB → LBA May 24, 17:40 UTCMay 24, 18:30 UTC50m
2026-05-24 EAI93D LBA → LBA May 24, 15:55 UTCMay 24, 16:50 UTC55m
2026-05-24 EAI92B DUB → LBA May 24, 14:15 UTCMay 24, 15:05 UTC50m
2026-05-24 EAI39V LPL → DUB May 24, 12:30 UTCMay 24, 13:15 UTC45m
2026-05-24 EAI19L DUB → LPL May 24, 11:00 UTCMay 24, 11:35 UTC35m
2026-05-24 EAI34N ABZ → DUB May 24, 08:35 UTCMay 24, 10:00 UTC1h 25m
2026-05-24 EAI42A DUB → ABZ May 24, 06:45 UTCMay 24, 07:50 UTC1h 5m
2026-05-23 EAI09U SOU → DUB May 23, 19:00 UTCMay 23, 20:10 UTC1h 10m
2026-05-23 EAI8C DUB → SOU May 23, 17:05 UTCMay 23, 18:15 UTC1h 10m
2026-05-23 EAI57K EDI → DUB May 23, 15:10 UTCMay 23, 16:05 UTC55m
2026-05-23 EAI6RC DUB → GLA May 23, 13:10 UTCMay 23, 14:05 UTC55m

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

Mode-S 4CAD51 frequently asked

What is Mode-S code 4CAD51?
4CAD51 is an ICAO 24-bit transponder address. Allocated to Ireland. Assigned to EI-HDK.
Where is Mode-S 4CAD51 registered?
Mode-S code 4CAD51 is allocated to Ireland (IE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4CAD51 broadcasting right now?
No active broadcast right now. Last signal was 4h ago.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4CAD51, octal 23126521, decimal 5,025,105.
What flights does 4CAD51 operate?
Mode-S 4CAD51 has broadcast 20 distinct callsigns, including EAI93D, EAI09U, EAI95C, EAI8C, EAI92B.