The wreckage of a Wings of Alaska Cessna 207 that crashed Friday, 18 miles from Juneau, was flown to Juneau International Airport by helicopter early Monday so a federal agency can investigate the flight equipment, the National Transportation Safety Board’s regional office chief said.

On Sunday, a recovery crew including NTSB investigator Chris Shaver traveled to the crash site, 1,330 feet above sea level in the forested mountains near Point Howard.

“They were able to prep the airplane wreckage to be flown out by helicopter,” NTSB Alaska regional office chief Clint Johnson said.

The weather was too poor to transport the plane parts Sunday, however, and the team had to return to the beach early Monday morning to pick up the wreckage and fly it to Juneau, Johnson said. The helicopter carried the plane in a net hanging from the bottom of the craft.

“It’s everything that belongs to a Cessna 207,” Johnson said. “The entire airplane was transported back to Juneau.”

The debris was stored in a hangar at Juneau International Airport.

Now, “there’s a fair amount to do” to investigate the reason behind the crash, Johnson said. The Cessna’s engine will be removed from the wreckage and shipped to the NTSB office in Anchorage or its manufacturer in Alabama to be analyzed. The airplane’s avionics, its onboard electrical systems, will also be looked at, Johnson said.

Shaver will interview Federal Aviation Administration personnel; friends and family of pilot Fariah Peterson, who died in the crash; Wings of Alaska management and pilots; and the surviving passengers of the Cessna 207, although “their health is first and foremost,” Johnson said. NTSB is “working very closely with the management team at Wings (of Alaska)” and has “a very good working relationship with them at the present time,” he said.

The body of Peterson, 45, of Birmingham, Alabama, was recovered from the crash site late Saturday by Shaver, Alaska State Troopers and members of Juneau Mountain Rescue, Johnson said.

Shaver began investigating the crash at that time, Johnson said. A preliminary report on the crash will be released near the end of the week, but the full NTSB investigation will likely take nine to 12 months to complete, he said.

“We are very much in the preliminary stages,” Johnson said. “It’s too soon to address cause or possible causes.”

The federal agency is now heading the operation, a spokeswoman for the Alaska State Troopers said.

Crash survivors Sandra Herrera Lopez, 60, of Juneau, and Ernestine Hanlon-Abel, 64, of Hoonah, are both still hospitalized and in serious condition in the intensive care unit at Harborview Medical Center in Seattle, a hospital spokeswoman said.

Hanlon-Abel’s cousin, Juneau’s Irene Knudson, said Hanlon-Abel went into surgery Monday morning and is “doing fine.”

The two other passengers, Humberto Hernandez-Aponte, 57, of Juneau, and Jose Vasquez, 15, of Puerto Rico, continued to be in stable condition Monday, according to a hospital spokesman.