A report on the plane crash near Denali earlier this month that left five people dead in Denali National Park and Preserve offers no indications of why the flight went down – but a glimpse of the survivors’ last moments in the stricken aircraft.

The National Transportation Safety Board released its preliminary report Thursday on the Aug. 4 crash of the K2 Aviation de Havilland Beaver. Michigan pilot Craig Layson died in the crash, along with four Polish tourists, who will not be identified at the request of their government.

According to the report, the flight was intended to be a one-hour tour of various glaciers including the Kahiltna Glacier and its Denali Base Camp originating and ending in Talkeetna. The plane took off at 5:05 p.m., before striking the Thunder Mountain ridgeline at an altitude of nearly 11,000 feet. The plane’s emergency locator transmitter began sending a signal at 5:53 p.m.

At about 6 p.m., K2 Aviation officials received a satellite phone call from Layson.

“The pilot stated that they had impacted a mountain and needed rescue,” NTSB officials wrote. “The call only lasted a couple minutes before the connection was lost. After several attempts, contact was once again made with the accident pilot, and he stated that he was trapped in the wreckage and there were possibly two fatalities. No further information was received before the connection was once again lost.”

On Aug. 6, a park ranger suspended from a helicopter was able to visit the crash site, finding four of the plane’s occupants, but had to leave after about five minutes, the NTSB said, due to deteriorating conditions. A second visit by rangers on Aug. 10 found the fifth victim in the plane’s rear section – after which park officials deemed the wreck in a crevasse of a hanging glacier too dangerous to recover.

National Park Service spokeswoman Katherine Belcher said rangers didn’t find any sign that people had tried to leave the aircraft.

“There were no signs of any disturbance at the aircraft or in the immediate vicinity,” Belcher said.

Snow which filled the plane after the crash kept rangers from finding any signs of how long people may have lived after the crash.

“We have no way to know that,” Belcher said. “All that we know is that the pilot made a call an hour after the crash and that he reported there were injuries.”

Clint Johnson, the NTSB’s Alaska chief, said there weren’t even any immediate theories regarding why the plane might have struck the ridgeline.

“At this point right now, we truly don’t know,” Johnson said. “We are just getting started on this thing.”

Two investigators were still working on the crash, with assistance from a meteorologist in Washington, D.C. Although the NTSB didn’t have any plans to revisit the crash site, Johnson said “hundreds” of photos taken by the Park Service on its last visit were still being reviewed.

“Obviously, this was a very painful accident, not only for the families not only for the operator, but for Talkeetna in general,” Johnson said.

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