The sole survivor of Friday’s plane crash remained in critical condition at a Seattle hospital Monday afternoon.

Twenty-one-year-old Morgan Enright is in the intensive care unit, said Harborview Medical Center spokesperson Susan Gregg.

Enright, from Ketchikan, was a passenger in a Cessna 206 that crashed into southern Admiralty Island Friday morning on its way from Wrangell to Angoon.

The pilot, 60-year-old David Galla, and two other passengers, 61-year-old Greg Scheff and 57-year-old Thomas Siekawitch — all Wrangell residents — died. Alaska State Troopers and Juneau Mountain Rescue recovered their bodies on Saturday.

NTSB’s Alaska Regional Chief Clint Johnson said this is the first fatal plane accident in Alaska in 2016.

After first getting airlifted to Juneau’s Bartlett Regional Hospital on Friday, Enright was medevaced to Seattle early Saturday morning.

Enright’s mother, Chere Klein, has been writing updates on Enright’s condition on the website CaringBridge.

On Sunday evening, she wrote: “Morgan is in extremely critical condition at Harborview Medical Center. The next few days are vital to her recovery. She has an amazing team of health professionals overseeing her care and her family by her side. Thank you for your continued prayers; we are so very grateful for the support.”

Around noon on Monday, Klein gave this update: “Morgan is still in extremely critical condition but each hour that passes is a positive step forward. We appreciate your continued prayers during this time.”

In a hangar in Juneau, investigators with the National Transportation Safety Board are piecing together the airplane wreckage.

“We’ll lay it back out the way it was and the way it normally is, and start documenting any fractures, markings — anything like that we’ll be looking at,” said lead investigator Shaun Williams, who works out of NTSB’s Anchorage office.

For the most part, the plane was still in one piece when it impacted a snow-covered terrain at about 2,200 feet, Williams said.

On Saturday, he and another NTSB investigator conducted the initial on-scene portion of the investigation.

“We documented everything and took reference points so we can go back and actually determine the angle of the terrain, the angle of the impact,” Williams said.

He said they removed the GPS unit that was on board the Cessna and will send it to NTSB headquarters in Washington, D.C. for download.

The wreckage had to be taken apart on Sunday and brought back to Juneau in three loads. Two arrived by helicopter Sunday, and the third, Monday.

The initial stages of the investigation focus on documentation, Williams said. The main portion focuses on three areas — “man, machine and environment.”

“By man, we’re going to be looking at the pilot — training records, training history, fleet, all of it. Machine is obviously the airplane, going over it with a fine-tooth comb. That’s what we’re doing here, documenting everything, and then we’ll compare it to records when we get back and when we get all the maintenance records collected,” Williams said. “And then for environment, we’ll be looking at the weather, the winds, air traffic and anything else that’s out there that we can grab from.”

He added that a senior meteorologist at NTSB headquarters in D.C. is conducting a detailed weather study.

The NTSB investigators also have representatives from Cessna Aircraft Company and the plane’s propeller manufacturer, Hartzell Propeller, helping with the investigation. The engine will be sent to its manufacturer, Continental Motors, in Mobile, Alabama for investigation.

Williams said an investigation normally involves interviews with any survivors.

“Right now we want to focus on (Enright) getting better, so we’re not going to push that. When she recovers and feels up to talking with us, if she feels up to talking with us, then we’ll speak to her at the time,” he said.

The Cessna was registered to Wrangell’s Sunrise Aviation, owned by Galla and Tyler Robinson. Williams said he’d be talking with the business during the investigation.

“On behalf of the NTSB, we want to extend our condolences to the families, at the same time, thank the first responders. Sitka and Juneau mountain rescue groups were tremendous in the rescue and recovery efforts,” Williams said.

Williams said a preliminary NTSB report will be out in five to 10 days. The full report could take up to a year, and a probable cause will be issued one to two months after the full report.

On the CaringBridge website, Enright’s mother Chere Klein said people can send cards to: Harborview Medical Center, Attn: Morgan Enright, 325 Ninth Avenue, Seattle, WA 98104. She politely requested that people not send flowers or balloons since Enright is located in the intensive care unit.