Romanian investigators say a small plane carrying medics that killed two people when it crashed into a remote mountain area was unable to fly at a safe height because its engines iced up.

The January 2014 crash in thick fog caused public outrage because it took a woodcutter and local residents 4 ½ hours to reach the injured while rescue services arrived even later. Everyone on board initially survived.

Civil aviation investigator Eugen Suciu, presenting conclusions from a 150-page report, said Monday that the aircraft's engines iced up and it flew too low for safety. One of the pilots and a medical student died of hypothermia among other causes after waiting for hours in deep snow to be saved. Four senior officials, including the interior minister, resigned or were fired.