According to a federal official, the pilot who survived a helicopter crash that killed five passengers told investigators he believes a passenger’s bag might have hit an emergency fuel shutoff switch in the moments before the chopper went down. Additionally, the National Transportation Safety Board also is scrutinizing why an emergency flotation device apparently didn’t deploy properly when the tour helicopter went down in the East River. The floats are supposed keep a helicopter upright; the Eurocopter AS350 that crashed Sunday overturned and submerged. The National Transportation Safety Board investigators began working to find out what caused the crash, which killed a Texas firefighter, an Argentine woman, a young video journalist and two others who were on a charter flight to take photos. Pilot Richard Vance managed to free himself from the rapidly sinking chopper, and was the only survivor. The owner of the helicopter, Liberty Helicopters, has been involved in at least five incidents in the last 10 years, according to FAA data. An August 2009 collision over the Hudson River between a Liberty chopper and a small, private plane killed nine people, including a group of Italian tourists.