Anniversary of NE Iowa Plane Crash, Cause Still a Mystery

DUBUQUE, Iowa (AP) — Questions remain nearly a year after a single-engine plane crashed and killed its pilot on the outskirts of Dubuque, including why the aircraft went down.

Dubuque physician and Libertarian U.S. Senate candidate Doug Butzier was killed in the crash Oct. 13, 2014. The National Transportation Safety Board hasn't determined the probable cause of the crash.

Butzier was headed home from a campaign event in West Des Moines. A preliminary report on the crash says he was relying on instruments rather than sight during his approach at Dubuque Regional Airport, possibly due to rainy conditions. The plane crashed during a second landing attempt.

Butzier's widow, Ann, says she has accepted that the cause of the crash might never be known.