The 78 year old man who crashed his plane on Molokai December 10, did not have medical clearance to fly.
Federal Aviation Administration documents show pilot William Vogt's medical certificate expired in March.
He needed clearance because he wears corrective lenses for near and distant vision.
Vogt and his 74 year old wife, Lynn, died when the plane crashed four miles west of the Molokai Airport.
The National Transportation Safety Board is investigating.
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Family, friends identify victims in deadly Molokai plane crash