National Transportation Safety Board investigators have begun the work of determining why a Wrangell plane crashed Friday morning on Admiralty Island.Download AudioRescuers work at the site of a crashed small plane on Admiralty Island on Friday. (Photo courtesy Sitka Mountain Rescue)Three people died and a fourth was badly injured when the Cessna 206 hit the 2,200-foot elevation about 20 miles southeast of Angoon.Alaska State Troopers identified the victims as 60-year-old David Galla, 61-year-old Greg Scheff and 57-year-old Thomas Siekawitch, all of Wrangell.The fourth person on board was 21-year-old Morgan Enright, who is from Ketchikan. She was rescued and medevaced to Seattle.As of Monday afternoon, she remained in critical condition at the Harborview Medical Center’s intensive care unit.Safety Board Investigator Shaun Williams says a preliminary report will be issued in five to 10 days. But a final determination of cause could take around a year.“All wreckage has been recovered,” said Williams. “It is in Juneau in a hangar and we are actually conducting a detailed wreckage layout examination at this time.”He says representatives of the frame, engine and propeller manufacturers will help with the investigation. He says the plane was relatively intact at the crash site and was removed in three pieces by helicopter.Meanwhile, Wrangell residents are mourning the loss of three members of their 2,400-person town.Jeff Jabush is the Southeast Alaska community’s borough manager“Everybody just knows everybody, it seems like,” Jabush said. “And it is hard when something bad happens to people, because everybody is involved in the whole thing.”He says community members are pitching in to help families of the victims.Jabush knew all three people killed in the crash.He says Galla was a longtime pilot who also served on a local electrical commission board. Scheff was a surveyor who worked around Southeast Alaska. Siekawitch worked for Scheff’s business.Wrangell medical provider Alaska Island Community Services is offering assistance to community members.The crashed plane was flying from Wrangell to Angoon. It’s owned by Wrangell’s Sunrise Aviation. Galla, the pilot, was one of the owners.