Ryanair flight to Madrid is declaring an emergency and returning to Dublin.
The Ryanair flight departed Dublin at 08:20 GMT for a 2-hour flight to Madrid.
About one hour into the flight, the crew declared an emergency (squawk 7700) and turned around.
The flight is operated by a Boeing 737-800 (registration EI-EBD), of 15 years old.
UPDATE 09:40 GMT
The flight #FR10 is returning to DUB.
UPDATE 10:05 GMT
The aircraft is suffering a depressurisation issue, pilots confirmed to ATC, source.
UPDATE 10:20 GMT
The Boeing 737-800 has landed on runway 28L.
Ryanair spokesman confirmed later that the plane had deployed its oxygen masks before making a controlled descent back to its point of origin.