The victims also included the pilot of the de Havilland DHC3 Otter that went down shortly after 11 a.m. Sunday at the airport in Soldotna, about 75 miles southwest of Anchorage on the Kenai Peninsula, authorities said.
The Federal Aviation Administration said the Otter was operated by Rediske Air, based out of Nikiski, another Kenai Peninsula community. Rediske Air spokesman Andy Harcombe said the pilot of the downed plane was Nikiski-based Walter "Willie" Rediske.
The remains of the victims were sent to the State Medical Examiner's Office in Anchorage for autopsies and positive identifications. Soldotna police Officer Mark Berestoff said the South Carolina hometowns of those on board were not being released at this time.
Firefighters from Central Emergency Services were the first on the scene, Capt. Lesley Quelland told the Anchorage Daily News.
She said they found the plane crashed off the side of the runway and fully engulfed in flames. A big, black cloud of smoke was visible from the station, about three driving miles from the airport.
"We saw the plume immediately when we left the station," Quelland said, It took crews about 10 minutes to put out the fire.
The fire that consumed the aircraft initially kept firefighters from reaching the wreckage, Alaska State Troopers spokeswoman Megan Peters said.
Police said in a release through the Alaska State Troopers that weather at the time of the crash was reported to be cloudy with a light wind.
National Transportation Safety Board investigator Clint Johnson said initial, unconfirmed reports indicated the plane crashed after departure.
The NTSB is sending an investigative team from Washington that's scheduled to arrive on Monday afternoon. Also taking part will be Alaska-based investigator Brice Banning, who was called back from the Asiana crash in San Francisco.
For many Alaskans, flying across the state is common because of the limited road system, exposing residents to a litany of hazards, including treacherous mountain passes and volatile weather.
It's possible to drive from Anchorage to Soldotna, but it's about a four-hour trip as the highway hugs Turnagain Arm and then cuts through a mountain passage.
Soldotna, with a population of about 4,300, is on the banks of the Kenai River, and the area is busy this time of the year with people fishing for salmon.
Alaska has already seen a several plane crashes this year, including a June 28 crash that killed a pilot and two passengers on a commercial tour in the Alaska Range.
In another crash Saturday, two men had to swim to shore after their plane went down in the waters off Kodiak Island. The small plane crashed after its engine sputtered out, and the men swam about 50 yards, the Kodiak Daily Mirror reported.
The municipal airport is located about a mile from Soldotna's commercial business area and is adjacent to the Kenai River, according to the city's website.
The runway is 5,000 feet long and paved.