Apparatus

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sensors Mode-S transponder

4CA857

ICAO 24-bit transponder address · allocated to Ireland

Currently assigned to EI-EMO · BOEING 737-800

Hex
4CA857
Octal
23124127
Decimal
5,023,831
Country
IE
Tail
EI-EMO
Type
B738
No current signal · last broadcast Jul 26, 21:45 UTC
Flights observed
736
Distinct callsigns
20
Country
IE
Last broadcast
Jul 26, 21:45 UTC

Last known position

Most recent position reported by Mode-S 4CA857.

Country allocation

The ICAO 24-bit address 4CA857 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
RYR4PN Ryanair 7 2026-07-20
RYR3UR Ryanair 7 2026-07-20
RYR9RA Ryanair 6 2026-07-21
RYR83SL Ryanair 6 2026-07-21
RYR71LM Ryanair 6 2026-06-03
RYR70QN - 6 2026-07-21
RYR39ED Ryanair 6 2026-07-21
RYR1FF Ryanair 6 2026-06-03
RYR7209 Ryanair 5 2026-06-02
RYR6HR Ryanair 5 2026-06-02
RYR8UC Ryanair 4 2026-05-01
RYR8RB - 4 2026-06-16
RYR8HX Ryanair 4 2026-05-30
RYR89NK Ryanair 4 2026-07-21
RYR615 Ryanair 4 2026-06-02
RYR611A Ryanair 4 2026-05-30
RYR5AD Ryanair 4 2026-06-15
RYR5495 Ryanair 4 2026-07-26
RYR48ZK Ryanair 4 2026-07-21
RYR33EL Ryanair 4 2026-07-21

Recent flights last 50

DateFlightRouteTakeoffLandingDuration
2026-07-26 RYR6276 - Jul 26, 20:35 UTCJul 26, 21:45 UTC1h 10m
2026-07-26 RYR6277 NUE → KRK Jul 26, 16:30 UTCJul 26, 19:40 UTC3h 10m
2026-07-26 RYR5495 SVQ → RBA Jul 26, 14:20 UTCJul 26, 15:00 UTC40m
2026-07-26 RYR54MX - Jul 26, 12:55 UTCJul 26, 13:35 UTC40m
2026-07-26 RYR9EA BVA → RBA Jul 26, 09:50 UTCJul 26, 11:55 UTC2h 5m
2026-07-26 RYR15BZ RBA → BVA Jul 26, 06:15 UTCJul 26, 08:55 UTC2h 41m
2026-07-25 RYR55DP - Jul 25, 19:50 UTCJul 25, 22:35 UTC2h 45m
2026-07-25 RYR6352 - Jul 25, 15:30 UTCJul 25, 18:05 UTC2h 35m
2026-07-25 RYR3185 - Jul 25, 12:40 UTCJul 25, 14:25 UTC1h 45m
2026-07-25 RYR3184 RBA → BCN Jul 25, 10:05 UTCJul 25, 11:25 UTC1h 20m
2026-07-25 RYR4957 VLC → RBA Jul 25, 08:05 UTCJul 25, 09:10 UTC1h 5m
2026-07-25 RYR55YU - Jul 25, 05:45 UTCJul 25, 06:55 UTC1h 10m
2026-07-25 RYR9358 AHO → BOD Jul 25, 00:35 UTCJul 25, 01:00 UTC25m
2026-07-24 RYR9357 BOD → AHO Jul 24, 22:55 UTCJul 24, 23:30 UTC35m
2026-07-24 RYR6NH NUE → STN Jul 24, 19:25 UTCJul 24, 22:00 UTC2h 35m
2026-07-24 RYR994L NCE → DUB Jul 24, 15:55 UTCJul 24, 18:15 UTC2h 20m
2026-07-24 RYR5495 - Jul 24, 14:20 UTCJul 24, 15:00 UTC40m
2026-07-24 RYR54MX - Jul 24, 12:55 UTCJul 24, 13:35 UTC40m
2026-07-24 RYR2PQ STN → DUB Jul 24, 09:20 UTCJul 24, 12:10 UTC2h 50m
2026-07-24 RYR3NR EIN → VNO Jul 24, 05:55 UTCJul 24, 08:25 UTC2h 30m
2026-07-23 RYR2PQ STN → DUB Jul 23, 20:25 UTCJul 23, 23:10 UTC2h 45m
2026-07-23 RYR3NR EIN → VNO Jul 23, 16:25 UTCJul 23, 19:00 UTC2h 35m
2026-07-23 RYR5495 SVQ → RBA Jul 23, 14:45 UTCJul 23, 15:25 UTC40m
2026-07-23 RYR54MX RBA → SVQ Jul 23, 13:15 UTCJul 23, 14:00 UTC45m
2026-07-23 RYR778 SVQ → MAH Jul 23, 09:05 UTCJul 23, 10:45 UTC1h 40m
2026-07-23 RYR779 RBA → TLS Jul 23, 06:10 UTCJul 23, 07:45 UTC1h 35m
2026-07-22 RYR5495 - Jul 22, 21:40 UTCJul 22, 22:15 UTC35m
2026-07-22 RYR508H - Jul 22, 18:35 UTCJul 22, 20:45 UTC2h 10m
2026-07-22 RYR3262 SVQ → ORK Jul 22, 15:40 UTCJul 22, 17:50 UTC2h 10m
2026-07-22 RYR60DZ EDI → SVQ Jul 22, 04:20 UTCJul 22, 14:45 UTC10h 25m
2026-07-21 RYR48ZK VLC → TRS Jul 21, 19:50 UTCJul 21, 21:35 UTC1h 45m
2026-07-21 RYR33EL TRS → VLC Jul 21, 16:50 UTCJul 21, 19:00 UTC2h 10m
2026-07-21 RYR83SL PRG → KRK Jul 21, 15:20 UTCJul 21, 16:10 UTC50m
2026-07-21 RYR70QN - Jul 21, 13:15 UTCJul 21, 14:20 UTC1h 5m
2026-07-21 RYR9RA SKG → HHN Jul 21, 11:30 UTCJul 21, 12:25 UTC55m
2026-07-21 RYR39ED TRS → NAP Jul 21, 09:20 UTCJul 21, 10:20 UTC1h 0m
2026-07-21 RYR17PY CTA → TRS Jul 21, 07:05 UTCJul 21, 08:30 UTC1h 25m
2026-07-21 RYR89NK TRS → CTA Jul 21, 04:50 UTCJul 21, 06:10 UTC1h 20m
2026-07-20 RYR3UR CTA → VCE Jul 20, 20:35 UTCJul 20, 21:50 UTC1h 15m
2026-07-20 RYR4PN TLL → BGY Jul 20, 18:30 UTCJul 20, 19:45 UTC1h 15m
2026-07-20 RYR78ZG BDS → TRS Jul 20, 16:25 UTCJul 20, 17:35 UTC1h 10m
2026-07-20 RYR4WD BLQ → STN Jul 20, 14:25 UTCJul 20, 15:30 UTC1h 5m
2026-07-20 RYR907P - Jul 20, 12:25 UTCJul 20, 13:30 UTC1h 5m
2026-07-20 RYR5649 - Jul 20, 09:50 UTCJul 20, 10:35 UTC45m
2026-07-20 RYR48ZK VLC → TRS Jul 20, 07:05 UTCJul 20, 08:55 UTC1h 50m
2026-07-20 RYR33EL TRS → VLC Jul 20, 04:20 UTCJul 20, 06:20 UTC2h 0m
2026-07-19 RYR83SL PRG → KRK Jul 19, 21:25 UTCJul 19, 22:15 UTC50m
2026-07-19 RYR70QN - Jul 19, 19:20 UTCJul 19, 20:10 UTC50m
2026-07-19 RYR90EK - Jul 19, 17:20 UTCJul 19, 18:30 UTC1h 10m
2026-07-19 RYR5836 - Jul 19, 14:35 UTCJul 19, 15:50 UTC1h 15m

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

Mode-S 4CA857 frequently asked

What is Mode-S code 4CA857?
4CA857 is an ICAO 24-bit transponder address. Allocated to Ireland. Assigned to EI-EMO.
Where is Mode-S 4CA857 registered?
Mode-S code 4CA857 is allocated to Ireland (IE). All aircraft registered there receive a Mode-S address from a fixed block defined by ICAO Annex 10.
Is 4CA857 broadcasting right now?
No active broadcast right now. Last signal was Jul 26, 21:45 UTC.
Hex, octal, and decimal Mode-S codes: what's the difference?
The same 24-bit identifier expressed in different bases: hex 4CA857, octal 23124127, decimal 5,023,831.
What flights does 4CA857 operate?
Mode-S 4CA857 has broadcast 20 distinct callsigns, including RYR4PN, RYR3UR, RYR9RA, RYR83SL, RYR71LM.