A small airplane that crashed in Snohomish County on Friday, killing all four people aboard, was on a test flight when it broke apart midair and plunged to the ground.

Raisbeck Engineering of Seattle was having the Cessna 208B test flown in preparation for modifying the aircraft, according to an emailed statement Sunday from Hal Chrisman, president of Raisbeck.

Chrisman said the aircraft had not yet been modified. The flight crew included two “highly-experienced” test pilots, a flight test director and an instrumentation engineer who were collecting “baseline aircraft performance data,” Chrisman said. 

Raisbeck designs modifications that can help airplanes “fly faster, carry more passengers or cargo and improve flight range,” Chrisman said. The baseline data would allow the company to compare the plane’s performance before and after modifications.

The Cessna 208B crashed around 10:20 a.m. in a field east of Harvey Field Airport in Snohomish County, about an hour after taking off from Renton Municipal Airport. One witness said the aircraft appeared to have broken apart and caught fire before the crash.

According to the aviation tracking website FlightAware, a Cessna 208B with identifier tail number N2069B took off from Renton Municipal Airport at around 9:25 a.m. and flew north to the Everett area, where it completed several large circles and a series of ascents, descents, accelerations and decelerations before dropping 5,100 feet.


Reached by phone, Chrisman declined to comment further on the crash or the proposed modifications to the plane. “I think the most important thing is we were flying an aircraft in which we had not installed our modification yet,” he said.

Aircraft N2069B was owned by Copper Mountain Aviation of Alaska, according to the Federal Aviation Administration website. The company could not be reached Saturday. 

The National Transportation Safety Board and the Federal Aviation Administration are investigating the crash. Neither agency immediately responded to requests for comment Sunday.

The Snohomish County medical examiner has not yet identified the victims. Chrisman declined to comment on the crew members involved in the crash.

“All the members of the Raisbeck family are devastated by this tragic accident,” he said in the statement. “And while Raisbeck feels this loss deeply, we cannot begin to imagine the loss and pain of the families and other loved ones of these crew members.”