GROVE, Oklahoma - A plane crash that killed a Grove man is under federal investigation.

Bob Hudson's family said he was flying a Cessna 172 from Zena to Grove when the plane went down just a half mile from the grass strip where he took off.

He was the only person on board the plane.

The family said he was making the 10-minute flight so an aircraft mechanic could do some routine maintenance.

Hudson's daughter said her dad used his passion for flying to help others.

Hudson was well-known in the aviation community, and his family said he was well-loved around the world.

“He was a safe, careful pilot, who had a lot of experience in a lot of different kinds of planes,” said Hudson’s daughter, Callie Hudson.

She said her dad had been a pilot for as long as she can remember.

Flying started out as a hobby for him until he found a way to turn his lifelong love into making a difference for others.

“He wanted it to mean something,” Callie said. “He wanted it to have value and impact people's lives.”

Hudson was an engineer and a part-time preacher. He retired several years ago, and that's when he started his second career.

Callie said, “He was always searching for a group that could use his talents, and he found that in Mexico.”

Hudson was the aviation program administrator for Mexico Medical Mission in the Sierra Madre Mountains. He flew medical supplies to Mexico for the faith-based mission; his wife, Pam, always by his side.

“He and my mom moved there and built a house there and really just poured their lives into that work,” Callie said.

But their mission work provided more than just medical supplies - it filled Hudson's heart with a happiness his daughter said he searched his whole life to find.

“For so many years he would say to me, 'The minute you start pouring your life into other people you can stop looking for what's gonna make you happy. You'll just wake up one day and you'll be happy,’" Callie said.

Funeral services for Hudson are set for 10:00 Tuesday morning at the Calvary Baptist Church in Neosho, Missouri.

So far, investigators have not released what may have caused the crash, but Hudson's daughter said her dad was such a skilled pilot she thinks he may have had some sort of medical event.