SEATTLE — A federal safety agency said Saturday that four people who died when a small plane crashed north of Seattle last month were conducting test flights to gather baseline information before the Cessna 208B was modified with a new aerodynamic drag-reduction system.
On Saturday, the National Transportation Safety Board released its preliminary report on the Nov. 18 crash in Snohomish.
The crew of the Cessna 208B had already done three days of test flights, but the day before the crash they ended early because one of the crew members felt ill. The crew went back up the following day and was testing the Cessna’s aft center-of-gravity stall characteristics when the plane crashed, the agency said.
Witnesses said the airplane broke up in flight and descended in a near-vertical corkscrew to the ground, and several reported seeing a white plume of smoke as the airplane broke into pieces, the NTSB report said.
The Snohomish County medical examiner said three men from Washington were among the victims.
