Three Ryanair flights were carrying enough fuel when they made separate mayday calls in one day in Spain, a report has found.
The aircraft also operated within European standards when each pilot declared an emergency landing on July 26, the Irish Aviation Authority (IAA) said.
The Madrid-bound flights - from Stansted (London), Skavsta (Stockholm) and Palma (Mallorca) - were all diverted to Valencia after heavy thunderstorms swept across the country. In an interim report, the IAA confirmed each aircraft had carried fuel in excess of flight plan fuel requirements and diverted to Valencia with more fuel than needed.
The crew declared an emergency in accordance with EU-Ops when they calculated usable fuel for landing at Valencia was less than final reserve, it added. Each plane landed safely with more than a ton of fuel on board.
Ryanair chief executive Michael O'Leary welcomed the findings of the report, which was published on the company's website. "We hope that the Fomento (Spanish Ministry) will now accept Ryanair's invitation to inspect our operations in Dublin in order to put an end to the false claims and misinformation in the Spanish media in recent weeks about Ryanair's outstanding 28-year safety record," he said from Madrid.
The carrier's pilots had told investigators that Valencia air traffic control seemed to be overwhelmed with the traffic load diverted on the day, with one declaring a mayday when another flight was told to expect a 35-minute delay in landing.
The IAA recommended its Spanish counter, AESA, review delays into Madrid and consider if airlines should be told to carry extra fuel when using the airport, like at Heathrow in London.
Elsewhere, both the IAA and AESA are investigating a technical fault on a Ryanair flight in Spanish airspace on Sunday, when an aircraft was diverted to Madrid. The night before a Ryanair flight carrying 171 passengers from Bristol to Reus in north-eastern Spain made an emergency landing after being diverted to Barcelona when the pilot detected a problem.
However, Ireland's Department of Transport this week told the Spanish Ministry of Development that Ryanair's safety standards on its fleet of 300 Boeing 737 aircraft were on a par with the safest airlines in Europe.
It also gave assurances of the IAA's rigorous oversight of Ryanair's operations and invited them to send an expert delegation to the IAA to be briefed in detail on the oversight of Ryanair's operations.