A problem with refueling at Amsterdam-Schiphol airport grounded several dozen planes and hundreds of passengers on Wednesday, airport officials said.
"Aircraft Fuel Supply, a third party company that controls aircraft fuel supply, currently has a fault in their system," spokeswoman Willemeike Koster told AFP.
"That means that planes cannot be refueled right now, which is causing delays," she added.
No precise reason was given, but "it has no relation with the heat," the spokeswoman said.