A fatal 2014 plane crash that killed two Hageland Aviation pilots was caused by a routine training maneuver gone wrong, a report released Friday said.

The National Transportation Safety Board's final report on the April 8, 2014, crash concludes the pilot lost control of the Cessna 208B during a training flight, leading to a steep descent and crash that killed Derrick Cedars, 42, and Greggory McGee, 46.

The conclusion echoes the agency's factual report released earlier this week. The agency also released its final report on the 2013 St. Mary's crash that killed 4 people, including an infant, on Friday.

Cedars was the instructor pilot during the flight, with McGee the second-in-command.

Cedars' previous students described the training procedure to the NTSB, Alaska regional office chief Clint Johnson said Friday. A student would look away while Cedars maneuvered the plane, and then the student would correct for it -- a "very, very common training procedure," Johnson said.

In this case, though, the training maneuver went awry. About 21 minutes into the flight, the plane dropped sharply, falling a "tremendous" 16,000 feet per minute, Johnson said.

McGee, lacking experience in the airplane type, "did not appropriately respond" to the training maneuver, the report says, and Cedars failed to recover control of the plane in time to prevent the rapid fall.

The plane crashed roughly 22 miles southwest of Kwethluk in Southwest Alaska. Alaska State Troopers found both pilots dead at the site that evening.