SPRINGFIELD, Ill. (WTVO) — Federal aviation regulators on Tuesday released their findings on the 2020 plane crash that killed a former Springfield mayor and his wife.

The NTSB said that they cannot conclude for certain what brought down the small plane in the Central Illinois. The report lays out the possibilities of poor visibility and equipment failure.

Former Mayor Frank Edwards was piloting the plane when it crashed. The report found that he likely had no visibility and was relying on his instruments.