SAN FRANCISCO (AP) – Federal authorities have determined most of the close-calls reported since December 2016 at the busy San Francisco International Airport were caused by pilots. The East Bay Times reports Wednesday the Federal Aviation Administration found that in three instances planes lined up for wrong runways and taxiways due to pilot error. A fourth plane was mistakenly cleared to land in the wrong runway by a tower controller. The airport has been under more scrutiny since a July 8 incident involving an Air Canada plane that nearly landed on an SFO taxiway crowded with four fully loaded aircraft. That investigation is being led by the National Transportation Safety Board and it’s still ongoing. Since then, the airport has buttressed its ground radar system and shut down a confusing taxiway.