DENALI NATIONAL PARK -- A witness told safety investigators she saw the cargo plane that crashed Aug. 1 in Denali National Park and Preserve flying slowly with its nose down at a 30-degree angle before it suddenly pitched upward.

That according to a preliminary report on the accident that killed three people and ignited a small wildfire near the park entrance. The report, recently released by the National Transportation Safety Board, describes various witness accounts of the crash.

The plane went nearly vertical, one witness said, then stalled, rolled left and dove nose-first for the ground. She watched as two large mushroom clouds appeared in the sky, the report says.

The weather was clear with a high ceiling of clouds at the time of the crash, according to the witness.

Multiple witnesses told investigators they saw the plane flying slow and low over the park before it made a steep left bank and dove toward the ground, near the park entrance. No one reported seeing smoke coming from the plane.

The Fairchild C-123 cargo plane was carrying a large generator from Wolf Lake Airport in Palmer to Unalakleet, according to the report.