JUNEAU, Alaska — No definitive cause can be determined for the plane crash that killed former US senator Ted Stevens and four others last summer in Alaska, the National Transportation Safety Board said yesterday.
The board agreed at a hearing in Washington that “temporary unresponsiveness’’ of the pilot could be to blame, but the reasons can’t be determined. There were no flight data or cockpit voice recorders on board what officials described as a plane otherwise outfitted with state-of-the-art equipment. The front-seat passenger, who survived, was said to be asleep at the time of the crash.
The terrain-awareness-and-warning system had been inhibited, according to the safety board, meaning pilot Theron “Terry’’ Smith had only a few seconds rather than possibly 30 seconds to respond as the plane neared the mountain that it eventually slammed into.
Smith, 62, was among the five killed in the Aug. 9 crash of the single-engine de Havilland DHC-3T Otter floatplane. According to NTSB, he had been grounded from flying from March 2006 to April 2008 due to a stroke and had a family history of strokes.