JUNEAU, Alaska (AP) — A plane that crashed in Alaska’s Wrangell-St Elias National Park last month, killing two people, began a gradual right turn and a descent shortly before the accident, a preliminary report released Wednesday says.

The report on the crash, which killed the pilot and passenger, was released by the National Transportation Safety Board. It offered few details.

The flight was operated by Copper Valley Air Service, and the report cites an official with the company as saying it was a twice-weekly scheduled flight with a planned route from Gulkana to McCarthy to Dan Creek and back to Gulkana. The report states that the flight left Gulkana for McCarthy about 10:21 a.m. Feb. 4, and went down around 10:51 a.m. about 14 miles northeast of Chitina, which is southeast of Gulkana.

A preliminary data review showed that about two minutes before the crash, the plane began a gradual right turn to the south and began a descent, the report states. The wreckage was recovered for further review, according to the report.

Clint Johnson, chief of the agency’s Alaska region, said it’s too early to draw any conclusions. GPS data is “a part of the puzzle … but we don’t have all of the parts yet to be able to start putting it together,” he said.