Ryanair boss Michael O’Leary has slammed air traffic control (ATC) provider Nats for the “unacceptable” disruption caused over the past two days.
In a video message, the chief executive described Monday as “a very difficult day” with 250 flights cancelled, while a further 70 were axed on Tuesday.
He said: “We have been in contact with UK Nats.
“We still haven’t had an explanation from them [about] what exactly caused this failure yesterday and where were their back-up systems.
“It’s not acceptable that UK Nats simply allow their computer systems to be taken down and everybody’s flights get cancelled.”
Speaking from the airline’s operations centre at Dublin Airport, O’Leary went on: “We’ve had a very difficult day yesterday due to the UK Nats ATC failure.
“I’m sad to report that we had to cancel about 250 flights affecting the flights of about 40,000 passengers because of long delays to flight plans, crews running out of hours.
“Last night we had 20 aircraft that couldn’t get back to their home bases so they’re out of place for today.
“Today, unfortunately, it looks like we’re going to cancel about another 70 flights.
“That’s a very small number out of the 3,200 flights we’re planning but that doesn’t mean we’re not doing everything we possibly can to try to minimise the disruption for our passengers and their families.”
He added: “We hope by the end of today, Tuesday, that from tomorrow we’ll be running a normal operation.”
There is speculation the fault was caused by a French airline submitting a flight plan to Nats in the wrong format.
Nats would not comment on whether that was accurate.
It said on Monday the problem was the result of a “technical issue affecting our flight planning system”.
Former Nats controller Doug Maclean said he did not know whether the actions of a French carrier were to blame, but believed an “operational glitch” was likely to have happened.
Asked if the problem could reoccur, he replied: “I wouldn’t think that there’s much likelihood of a failure but as long as Nats don’t say anything it’s a perfectly legitimate question.”
He added: “What was the problem? I don’t understand why they’re so closed mouth about it.”
Downing Street did not rule out the possibility that an inputting error by a French airline could have caused the disruption.
The Prime Minister’s official spokesman said: “[I] think you’ll know that there’s going to be an investigation by the CAA [Civil Aviation Authority], and a report shared with government.
“I think [transport secretary] Mark Harper confirmed this morning he’ll be getting that in days.
“I’m not going to pre-empt that. I’ve seen, obviously, various bits of speculation, but I’m not going to pre-empt the work that needs to be done.”
But he added that experts had confirmed it was a “technical issue, not a cyber security incident”.
Asked if officials would speak to counterparts across the English Channel, the spokesman said “you would expect them to be speaking regularly” with other countries, “but I’m not aware of any specific conversations with French counterparts”.
Neil Lancefield – Press Association