Cockpit accident believed to be cause of nose dive on LATAM Boeing 787: WSJ

flight attendant hit a switch on the pilot's seat while serving a meal

"...According to the report, a LATAM Airlines flight attendant hit a switch on the pilot's seat while serving a meal, activating a motorized feature that pushed the pilot into the controls and sent the plane into a nose dive, the officials said. 

The switch has a cover and is not supposed to be used when a pilot is in the seat...