Downeast Airlines Flight 46

Downeast Airlines Flight 46 was a scheduled airline service in the United States from Boston's Logan International Airport to Rockland, Maine operated by Downeast Airlines. On May 30, 1979 a de Havilland Canada DHC-6 Twin Otter operating the flight crashed during a nonprecision approach to Rockland's Knox County Regional Airport. All but one of the 18 people on board were killed. The cause of the accident was controlled flight into terrain (CFIT) after the failure of the flight crew to stop the aircraft's descent below the minimum descent altitude for the non-precision approach at Knox County airport. The investigation into the accident looked into the airline's corporate culture as a contributing factor to the crash; this was the first time an investigation took this approach to an air crash.

The crash of Flight 46 is currently the deadliest to have occurred in the state of Maine. At the time of the crash, the crew had descended the Twin Otter below the minimum descent altitude in order to see the runway in heavy fog.