By Shirin Rajaee

CASTRO VALLEY (CBS13) – A Rocklin man died today in a small plane crash, and now his family and friends are stunned, wondering what went wrong.

The exact cause of the crash is a mystery. The single-engine Piper took off from Lincoln Tuesday morning headed to Oakland. But it went down in the hills near Castro Valley around noon.

John Sacco took off at 10:50 a.m. for what was supposed to be a 46-minute flight to Oakland, but sadly he lost contact with air traffic control around 11:30, just 12 miles east of Oakland. Friends CBS13 spoke to are devastated.

“It’s a sad day; loss to our community, loss of a friend, loss of a colleague,” said Bob Downey, Sacco’s colleague and friend.

Downey says he’s known Sacco for 10 years.

“John always had a kind word for people. He was just a nice guy, and that doesn’t leave a lot for people, but genuinely he was,” said Downey.

Sacco, a resident of Rocklin, was the sole person onboard the Piper PA-32 single-engine plane that took off Tuesday morning.

According to the FAA, air traffic controllers lost contact with the pilot at about 11:30 a.m.

Alameda County Fire Officials said that Sacco reported having engine trouble just before losing contact with air traffic controllers.

(Credit: Alameda County Fire Dept.)

(Credit: Alameda County Fire Dept.)

The plane was lost about 12 miles east of Oakland International Airport. And after an intensive search by Alameda County fire and sheriff’s units, just before 4, crews recovered the wreckage of the plane off Palomares Road in remote and rugged terrain.

“It just shocks me this would have happened,” said Sacco’s friend Alan Larson.

Larson told CBS13 by phone how he’s baffled, and that Sacco was such a meticulous pilot.

“He was very fastidious about his planning. He had a default setting. If it wasn’t good to go, he wouldn’t go,” said Larson.

Sacco was an industrial hygienist and safety engineer. Governor Jerry Brown had appointed him to the California Occupational Safety and Health Standards board.

“To have someone of John’s professional status and personal concern for people on the board was a real asset,” said Larson.

It’s clear he was respected in his profession and had a passion for flying.

“He was doing something he loved. And if you’re gonna go, it’s not such a bad way to go,” said.

We’ve been in contact with Sacco’s daughter and her boyfriend who are hearing of this tragic news while out of the country.

It’s heartbreaking to know they just spoke to him yesterday.