Zurich Airport reduced its incoming flight capacity by around 30% on Wednesday morning after a technical fault at the control centre of Swiss air navigation service Skyguide, based in Dübendorf (a town near Zurich). The malfunction caused a system used to track approaching aircraft to display delayed flights unreliably, forcing controllers to log flights manually as a safety measure. No cancellations had been reported at the time of writing, though delays were possible, compounded by seasonal Bise winds — a cold northeasterly common in Switzerland — which typically strain airport capacity on their own.