Airbus Helicopters Deutschland MBB-BK 117 B-2 crash near Perryville, Missouri, United States

Fuel starvation due to the pilot’s failure to turn on the fuel transfer pump switches during takeoff, which led to a total loss of engine power. Contributing to the accident was the pilot's improper decision to activate the annunciator panel’s dimming function during dusk, which prevented him from seeing the illuminated fuel transfer pump caution light indicating that the pumps were off and the illuminated caution lights for low fuel in the supply tanks.