A crash that killed two Hageland Aviation pilots during a training flight near Kwethluk in 2014 may have begun as a training maneuver, according to a new report.

Wednesday's National Transportation Safety Board factual report and docket of documents on the April 8, 2014 crash that killed Derrick Cedars, 42, and Greggory McGee, 46, said they were the Cessna 208 Caravan's instructor and training pilot respectively. Cedars had more than 14,000 hours of flight time, including nearly 6,000 in Caravans, while McGee had 593 hours of flight time with none in Caravans.

The report was the board's second on the same day involving a fatal Hageland flight, following the release of a factual report on the Nov. 29, 2013, crash that killed four people near St. Mary's.

In the 2014 crash, investigators said, Cedars and McGee took off from Bethel at about 3:35 p.m. About 21 minutes later, data being transmitted by the plane's ADS-B telemetry system tracked it crashing roughly 22 miles southwest of Kwethluk. Alaska State Troopers found both pilots dead at the site that evening.

No communications were received from the plane during the crash.

The Bethel airport, 27 miles northeast of the crash, reported winds from the north at 8 knots and clear skies three minutes before the Cessna's crash.

Johnathan Kapsner, a training pilot checked by Cedars who later became an instructor pilot at Hageland himself, told the NTSB he and Cedars would typically start a training pilot's stall maneuvers at an altitude of about 3,500 feet, with turns left and right before the plane entered a descent.

"The accident flight followed a typical routine and flight pattern from previous training flights," investigators wrote. "The accident sequence initiated during the time when a simulated emergency and descent was typically initiated."

Another Hageland training pilot, Jaime Burns, told investigators that after an emergency descent to 500 feet, Cedars had him descend further to an altitude of 200 feet and follow a waterway -- a maneuver he called "running the river."

"He said that although he hadn't done a low-flying maneuver like running the river before, he at no time felt unsafe," investigators wrote.

A preliminary 2014 report on the Kwethluk crash said the plane had experienced "altitude deviations" leading to a "rapid, steep descent" from an altitude of about 3,400 feet -- a pattern replicated by an NTSB computer simulation based on telemetry data from the crash and a physics model of the plane, which indicated instabilities beginning at 3:56 p.m.

"At this point, the airplane began a steep descent, which continued until impact," investigators wrote. "The simulation descent rate from (3:56 p.m.) to the time of impact steadily increased to a maximum of about 16,000 feet per minute. The elapsed time from the initial upset to the point of impact was about 22 seconds."

The NTSB gave heightened scrutiny in the report to the plane's trim system, which was controlled automatically in normal operations by the plane's autopilot. Investigators noted a warning in the manual for the Cessna's trim system that "up to 45 pounds of force on the control wheel may be necessary to hold the aircraft level" in the event of an autopilot failure.

The board's simulations of two possible scenarios for the crash indicated that moving the plane's elevators would've required applying up to 130 pounds of pushing force by the time of impact to its central column in a "normal" scenario -- or 800 pounds of pulling force in a "runaway pitch trim" scenario.

When investigators visited the crash site, on land at a bend in the Kwethluk River, they found a 200-foot debris path from the plane as well as initial impact sites, which suggested the plane hit the ground at a roughly 30-degree angle.

"Numerous sections of the severely fragmented airplane were located throughout the wreckage path," investigators wrote.

None of the plane's instruments were recoverable, in part due to a fire after the crash that consumed much of the cockpit and fuselage.