Photo courtesy KMGH-TV

A single-engine Cessna 182H went down en route to Boulder in Miner's Gulch, four miles west of Black Hawk, on Thursday, killing the pilot. The plane is registered to Barry Maggert, of Carbondale, and Carroll Winkler, of Glenwood Springs.

A fatal airplane crash last week near Black Hawk -- an accident that killed a University of Colorado student's father -- was caused by a partial loss of engine power, according to a preliminary report by the National Transportation Safety Board.

The crash killed the pilot, Barry Maggert, 47, of Carbondale, and injured the passenger, Jonathan Holton, 23. They were on their way to Boulder to watch one of Maggert's sons, Lee Maggert, graduate from CU when the single-engine Cessna 182 went down May 8.

Holton told investigators that the engine started sputtering after they passed over Eagle County Airport at 16,000 feet above sea level. Maggert radioed the Federal Aviation Administration to report engine troubles about 15 miles southwest of Boulder.

He attempted to troubleshoot the problem by adjusting the air-fuel mixture, but the plane soon began to descend in a nose dive, the report said. It crashed at 10,400 feet in the mountains about four miles west of Black Hawk.

Problems with the air-fuel ratio are a possible cause of engine failure, according to Jason Aguilera, air safety investigator for the NTSB based in Arlington, Texas. But the NTSB will not be able to confirm the crash's probable cause for several months or possibly a year.

"We haven't completed all of the investigation," Aguilera said. "There were parts of the airplane that we weren't able to examine on scene."

The preliminary report found that both wings of the Cessna were heavily damaged but remained attached to the plane. Upon recovery, the wreckage will be transported to a facility for further examination.

Contact Camera Staff Writer Jennifer Bronson at JEBronson@gmail.com.