ANCHORAGE, Alaska (AP) - The National Transportation Safety Board says a 75-year-old pilot killed last year in a crash in Anchorage was impaired by carbon monoxide.
Investigator Clint Johnson in a report released Monday says a floatplane piloted by James Hefty had a severely degraded and damaged muffler can assembly.
That likely allowed carbon monoxide to enter the cockpit before Hefty crashed Sept. 16 in an Anchorage residential neighborhood.
Toxicological examination of his blood showed a 48 percent level of carboxyhemoglobin (car-BAHKS-eh-hee-moh-GLOH-bin), formed when carbon monoxide binds to hemoglobin.
Levels from 10 to 20 percent can cause confusion and impaired judgment.
Witnesses told investigators the low-flying airplane made two 360-degree right turns at high power before hitting a tree and crashing.
A family member said such maneuvers would have been highly unusual for Hefty.
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