July 16 (UPI) -- A flight instructor was killed and a student was critically injured in a helicopter crash at a California airport, authorities said.
The city of Hayward said in a statement that the four-seat helicopter, registered to Pacific Helicopters flight school, crashed during an instructional flight at Hayward Executive Airport at about 2:30 p.m Monday.
The student was transferred to a local hospital, it added.
Hayward Fire Department said the helicopter crashed upside down, KPIX-TV reported.
Chuck Finnie, Hayward city public information officer, said the two individuals were the only ones on board the helicopter and were practising takeoffs and landings when the accident occurred, the San Fransisco Chronicle reported.
He added that he was unsure of who was helming the helicopter when it crashed.
Hayward Executive Airport Manager Doug McNeely said the crash happened unexpectedly.
"There was no mayday or distress call at the time," he said. "It happened very fast."
National Transportation Safety Board confirmed via Twitter that it would be investigating the crash.