Investigators don't expect to identify the cause of a small plane crash in northern Colorado that killed two people until next year.
Sixty-two-year-old flight instructor William Earl Allen of Broomfield, Colorado, and his student, Terry Lynn Stewart, 60, of Houston, Texas died in the crash on Rabbit Ears Pass near Steamboat Springs on Aug. 9.
A preliminary report released by the National Transportation Safety Board on Tuesday says it was sunny, calm and clear at the time of the crash. It doesn't say who was flying or include many other new details.
NTSB spokesman Peter Knudson told Steamboat Today says fatal investigations, including a finding of probable cause, usually take about a year to complete.
A handful of other planes have crashed in the area over the years.