ABSTRACT
On the evening of June 2, 1979, Downeast Flight 46, a de Havilland Twin Otter, crashed into a fog shrouded shoreline forest while on final approach to Rockland, Maine. Seventeen people were killed.34 The immediate cause of the crash was the failure of the crew to arrest the descent of the aircraft at the MDA (minimum descent altitude) of 440 feet. This resulted from the failure of the captain and first officer to monitor the instruments, which were indicating an unusually high rate of descent. The descent rate, in turn, resulted from an earlier error, the captain's mis-setting of the landing flaps to 20 degrees instead of 10 degrees. Traditionally the discovery of such a mistake would have largely 'wrapped up' the accident investigation and it would have been diagnosed as a clear cut case of pilot error.
