sensors Mode-S transponder
4CAF77
ICAO 24-bit transponder address · allocated to Ireland
- Hex
- 4CAF77
- Octal
- 23127567
- Decimal
- 5,025,655
- Country
- IE
- Flights observed
- 30
- Distinct callsigns
- 20
- Country
- IE
- Last broadcast
- 27d ago
Last known position
Country allocation
The ICAO 24-bit address 4CAF77 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 |
|---|---|---|---|
| RYR9YC | Ryanair | 1 | 2026-07-25 |
| RYR99SD | - | 1 | 2026-07-13 |
| RYR8UE | Ryanair | 1 | 2026-07-26 |
| RYR8931 | - | 1 | 2026-07-09 |
| RYR86DX | Ryanair | 1 | 2026-06-19 |
| RYR7XY | Ryanair | 1 | 2026-06-15 |
| RYR7HZ | Ryanair | 1 | 2026-06-04 |
| RYR72SR | - | 1 | 2026-07-08 |
| RYR6YQ | Ryanair | 1 | 2026-06-17 |
| RYR6GL | Ryanair | 1 | 2026-06-12 |
| RYR64VR | - | 1 | 2026-07-07 |
| RYR5JX | Ryanair | 1 | 2026-06-04 |
| RYR59QQ | Ryanair | 1 | 2026-05-20 |
| RYR49WG | Ryanair | 1 | 2026-06-24 |
| RYR47XV | Ryanair | 1 | 2026-05-24 |
| RYR45AL | - | 1 | 2026-07-05 |
| RYR44RQ | Ryanair | 1 | 2026-05-15 |
| RYR41NU | - | 1 | 2026-06-20 |
| RYR3RQ | - | 1 | 2026-06-19 |
| RYR35NU | - | 1 | 2026-06-23 |
Recent flights last 30
| Date | Flight | Route | Takeoff | Landing | Duration |
|---|---|---|---|---|---|
| 2026-07-26 | RYR8UE | VCE → SDR | Jul 26, 06:20 UTC | Jul 26, 06:30 UTC | 10m |
| 2026-07-25 | RYR9YC | BHX → AGP | Jul 25, 08:00 UTC | Jul 25, 08:10 UTC | 10m |
| 2026-07-13 | RYR99SD | - | Jul 13, 12:35 UTC | Jul 14, 06:10 UTC | 17h 35m |
| 2026-07-09 | RYR8931 | - | Jul 9, 23:15 UTC | Jul 9, 23:25 UTC | 10m |
| 2026-07-08 | RYR72SR | - | Jul 8, 05:30 UTC | Jul 8, 15:35 UTC | 10h 5m |
| 2026-07-07 | RYR64VR | - | Jul 7, 18:20 UTC | Jul 7, 22:45 UTC | 4h 25m |
| 2026-07-06 | RYR10TY | - | Jul 6, 17:10 UTC | Jul 6, 17:25 UTC | 15m |
| 2026-07-05 | RYR45AL | - | Jul 5, 19:35 UTC | Jul 5, 19:45 UTC | 10m |
| 2026-07-02 | - | - | Jul 2, 16:45 UTC | Jul 2, 20:45 UTC | 4h 0m |
| 2026-07-01 | RYR11GY | - | Jul 1, 22:10 UTC | Jul 2, 20:45 UTC | 22h 35m |
| 2026-06-25 | - | - | Jun 25, 21:10 UTC | Jun 25, 21:20 UTC | 10m |
| 2026-06-24 | RYR49WG | CRL → LPA | Jun 24, 15:05 UTC | Jun 24, 15:14 UTC | 10m |
| 2026-06-23 | RYR35NU | - | Jun 23, 20:44 UTC | Jun 23, 20:54 UTC | 10m |
| 2026-06-20 | RYR41NU | - | Jun 20, 09:24 UTC | Jun 20, 09:34 UTC | 10m |
| 2026-06-19 | RYR3RQ | - | Jun 19, 23:09 UTC | Jun 19, 23:19 UTC | 10m |
| 2026-06-19 | RYR160Z | LTN → NOC | Jun 19, 17:24 UTC | Jun 19, 17:34 UTC | 10m |
| 2026-06-19 | RYR86DX | NRN → NDR | Jun 19, 16:04 UTC | Jun 19, 16:14 UTC | 10m |
| 2026-06-17 | RYR6YQ | FAO → NRN | Jun 17, 22:15 UTC | Jun 17, 22:25 UTC | 10m |
| 2026-06-16 | RYR185L | DUB → MRS | Jun 16, 06:10 UTC | Jun 16, 06:20 UTC | 10m |
| 2026-06-15 | RYR7XY | TIA → NRN | Jun 15, 06:24 UTC | Jun 15, 06:35 UTC | 10m |
| 2026-06-12 | RYR6GL | SVQ → BUD | Jun 12, 16:45 UTC | Jun 12, 16:55 UTC | 10m |
| 2026-06-11 | - | - | Jun 11, 09:20 UTC | Jun 11, 09:30 UTC | 10m |
| 2026-06-04 | RYR7HZ | PMI → HAM | Jun 4, 07:35 UTC | Jun 4, 07:45 UTC | 10m |
| 2026-06-04 | RYR5JX | HHN → PSR | Jun 4, 05:45 UTC | Jun 4, 05:55 UTC | 10m |
| 2026-05-31 | - | - | May 31, 09:05 UTC | May 31, 09:15 UTC | 10m |
| 2026-05-24 | RYR47XV | ALC → BHX | May 24, 06:15 UTC | May 24, 06:25 UTC | 10m |
| 2026-05-20 | RYR59QQ | STN → LIS | May 20, 08:30 UTC | May 20, 08:40 UTC | 10m |
| 2026-05-15 | RYR44RQ | STN → ALC | May 15, 16:35 UTC | May 15, 16:45 UTC | 10m |
| 2026-05-13 | - | - | May 13, 17:35 UTC | May 13, 17:45 UTC | 10m |
| 2026-05-09 | - | - | May 9, 18:25 UTC | May 9, 18:35 UTC | 10m |
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.