Federal investigators have released their preliminary report on a deadly plane crash in Arundel earlier this month.

Pilot Eldon Morrison, 81, and his passenger, 55-year-old Paul Koziell, were flying to Biddeford Municipal Airport on Oct. 5 after a business trip in Presque Isle when the weather became rough, according to the National Transportation Safety Board.

The plane approached the airport at about 200 feet lower than it should have, investigators found.

But the preliminary report doesn’t reach a conclusion about exactly what caused the crash. The plane hit a tree about 40 feet off the ground and caught fire after it crashed.

Morrison had more than 2,500 total flight hours, more than 900 of them in that plane.

Morrison and Koziell died in the crash.

Morrison was the founder and CEO of CPM Constructors and the father-in-law of Koziell, who served as the company’s president and was married to one of Morrison’s three daughters, Denise.

CPM has done dozens of projects for the Maine Department of Transportation and Maine Turnpike Authority, including replacing two Interstate 295 bridges over Route 1 near Exit 17 in Yarmouth, reconstructing the historic Cribstone Bridge in Harpswell and working on Exit 45 of the Maine Turnpike interchange in South Portland.

Morrison founded the company in 1985, and grew it to about 85 employees in Maine, New Hampshire and Vermont. He was a well-known philanthropist, having funded the Millard Pray scholarship, named after his friend and former business partner, through the Maine Better Transportation Association.

He also established the Dianne Morrison Research Scholarship, in honor of his wife, at the University of Maine, where he earned his civil engineering degree in 1964. They both grew up in Washington County.