William Gaddis Sr. was about 10 minutes into his first flight in the ultralight aircraft he had built when it crashed into trees Sunday across the street from his backyard landing strip in North Yarmouth.

His son and a neighbor got to the crash site and saw him in the plane, suspended about 60 feet off the ground by branches. They urged him to stay where he was, but Gaddis, 75, climbed free.

He made it down about 20 feet before he fell, after losing his grip or having a branch break under him, said the Cumberland County Sheriff’s Office. Gaddis died late Sunday after being flown by LifeFlight helicopter to Maine Medical Center in Portland.

His family could not be reached for comment Monday.

Darlene Doughty, vice president of Yankee Ultralight Flyers, based in Seacoast New Hampshire, said it’s important for pilots of ultralights to realize that their simple engines can cut out at any time, and to plan ahead.

Landing in trees “can be one of the safest things to do,” she said. “You better be looking for soft fuzzy trees.”

Shawn Moody, a former candidate for governor who has flown ultralights and light sport planes extensively out of Gorham, said, “You can actually glide or fly into the treetops. There’s a high probability, most of the time, the trees will support the weight of the aircraft.

“You want to go into hardwood trees,” he said. “There are very small branches that will catch the wings and fuselage, and support it, really, and bend. Pine trees will not give. The wings will break off.”

Moody said, “When we would fly ultralights, we would actually carry rope inside for situations like this,” to get out of a tree safely.

Moody said he did not know Gaddis.

No pilot’s license is required to fly an ultralight, a single-seat aircraft that weighs no more than 254 pounds empty, carries no more than five gallons of fuel and goes no faster than 64 mph.

Many ultralights are powered by two-cycle snowmobile engines and can be prone to mechanical problems, especially the first time out, said Moody.

The urge to climb free of a small plane in a tree can be irresistible, said John Pompeo, a flier who is a friend of Moody’s.

When he was in his 20s and new to flying, Pompeo crashed his Phantom Ultralight into the tops of trees.

It fell through the canopy before catching about 20 feet off the ground.

With gas pouring from the ruptured tank, Pompeo unstrapped himself and jumped. He survived without injury, but he chalks it up to his youth.

“It’s kind of natural instinct when you’re in that situation. The natural instinct is to try to get out of the plane,” he said.

It’s unclear what caused Gaddis to crash.

He took off from his home at 367 Mill Road around 7 p.m. and went down in tall trees at 354 Mill Road, according to the sheriff’s office, which responded to the crash.

The case remains under investigation.

Staff Writer David Hench can be contacted at 791-6327 or at: dhench@pressherald.com