A Federal Aviation Administration spokesman said Monday that an investigation into Sunday’s plane crash that claimed the life of a well-respected Maine businessman and aviation pioneer could take months to complete.

Telford Allen II, 64, founder of Telford Aviation Services in Waterville and later Bangor, was the pilot of a Cessna 185 floatplane that crashed into Moosehead Lake just before 2:30 p.m. Sunday.

According to police, Allen attempted to land his floatplane near his home in Rockwood at the mouth of the Moose River off Route 6. Allen reportedly was flying back from Rangeley with a passenger at the time.

Initial reports from the scene indicated that the wheels to the floatplane might have been down and caused it to flip over and end up upside down.

Jim Peters, a spokesman for the Federal Aviation Administration in New York, said Monday that the crash would be investigated by the National Transportation Safety Board, which is called in whenever there is an aviation fatality. The investigation is likely to take up to six months to complete.

Allen’s flying companion, Natalie Holmes-Moody, 61, of Rockwood, was injured in the crash but her injuries were not considered life-threatening.

Allen, who lived in Rockwood near Greenville, was well-respected and well-liked member of the community.

“He was just a great guy, a prince of a man,” said Greenville Town Manager John Simko. “Anything he touched turned to gold. But, although he was a man of … means, he was always very humble and very genuine.”

Allen was born Nov. 2, 1945, in Philadelphia, the son of Telford and Charlotte (Loud) Allen. He was 17 when he first got his pilot’s license and began his career as a bush pilot for Folsom’s Air Service in Greenville, according to his obituary.

Allen founded Telford Aviation in 1982 in Waterville as a small charter flight company. In the 1990s, he moved the company to Bangor International Airport, where it became a regional and national leader in both airplane parts sales and maintenance.

The company was sold last year to ACC Holding LLC of Milwaukee, Wis., several years after Allen turned the business over to his sons, Telford Allen III and Travis Allen.

As successful as his business was, Allen remained in Maine and often gave back, including his involvement with the Greenville International Sea-Plane Fly-in. John Pepin, a local business owner, worked with Allen on the event.

“Telford was just a really good guy. He was well-respected,” Pepin said. “People enjoyed working with him.”

Simko and Pepin agreed that Allen was an expert pilot and declined to speculate about how the plane crash occurred.

“I guess we’ll have to wait and see,” said Pepin. “It looks to be just a tragic accident.”