A single engine turboprop airplane - possibly carrying children on a ski trip - nose-dived into a cemetery as it approached the Butte airport Sunday afternoon, killing 14 to 17 people aboard, a federal official said. The aircraft crashed and burned at Holy Cross Cemetery, 500 feet short of Bert Mooney Airport, said Federal Aviation Administration spokesman Mike Fergus. An investigator with the National Transportation Safety Board offered few details at a press conference in Butte Sunday night. No cause of the crash was given. "We are just beginning our investigation," said Kristi Dunks. "We don't have a lot of information at this time. "Certain family members were contacted," she said. "At this point, I don't have an exact number." A California newspaper, the Napa Valley Register, reported on its Web site late Sunday that a family of five from St. Helena, Calif., including three preschoolers, was among the victims. Dunks would not say if there had been a distress call from the pilot. It was partly cloudy, the visibility was 10 miles and winds were blowing from the northwest around 10 mph at the time of the crash, according to hourly temperature information from the National Weather Service. The aircraft had departed from Oroville, Calif., and the pilot had filed a flight plan showing a destination of Bozeman, about 85 miles southeast of Butte. But the pilot canceled his flight plan at some point and headed for Butte, Fergus said. Preliminary reports indicate the dead include numerous children, he said. "We think that it was probably a ski trip for the kids," Fergus said. Butte Silver-Bow Sheriff John Walsh said there were a few people at the cemetery at the time of the crash, but no one on the ground was injured. He would not describe witness reports. Steve Guidoni of Butte said he was driving by the cemetery and saw the plane nosedive into the ground. He stopped and ran over to see if he could help. "It smelled like diesel fuel to me," said Guidoni, 61. "There was nothing left of it. It just went straight into the ground. I went over there to try to help. I thought maybe I would pull someone out of the fire." Guidoni said he saw luggage and seat cushions lying around, but no bodies. He said the biggest piece of the plane was the size of a kitchen table. "You wouldn't even know a plane was there," he said. Nick Dipasquale, 19, was working at a gas station across the street. "I heard a loud bang," he said. "It sounded like someone ran into the building." He said he ran outside to see flames as tall as the trees. Dipasquale said people who were fueling their cars said they saw the plane flying low, begin a turn, start to wobble and then slam into the ground. Fergus said the Pilatus PC-12 aircraft was manufactured in 2001. The Pilatus PC-12 is a single-engine turboprop aircraft designed and manufactured by Pilatus Aircraft of Switzerland. It is certified for 12 persons on board and typically seats 6-9 passengers plus 1-2 pilots. The PC-12 has a range of 1,750-2,600 miles and cruises at approximately 300 miles per hour, according to Flight Aware, a Web site that tracks air traffic. The plane was registered to Eagle Cap Leasing Inc. in Enterprise, Ore., Fergus said. He didn't know who was operating the plane. I. Felkamp is listed in Oregon corporate records as Eagle Cap's president. Attempts to reach him by phone were unsuccessful. The flight originated at Brown Field Municipal airport in San Diego on Saturday evening and flew to Redlands, Calif., about 100 miles north, said Rachel Laing, a spokeswoman for the city of San Diego. The plane left Sunday morning for Vacaville, Calif., according to Flight Aware. From there it flew to Oroville, Calif., and then to Butte. The NTSB could not confirm that information. "We are still gathering the information of the aircraft, it's purpose, what they were doing and where they were going," Dunks said. In Oroville, Calif., Tom Hagler said he saw a group of about a dozen children and four adults Sunday morning at the Oroville Municipal Airport, about 70 miles north of Sacramento. Hagler, owner of Table Mountain Aviation, described the children as ranging from about 6- to 10 year olds. He let the children into his building to use the restroom. "There were a lot of kids in the group," he said. "A lot of really cute kids." Hagler said he showed the pilot where he could fuel his plane, and the pilot said he expected his flight to take two-and-a-half hours. The pilot didn't file a flight plan at the Oroville airport. The crash is the fourth major plane accident in the US in slightly more than three months. On Dec. 20, Continental Airlines plane veered off a runway and slid into a snowy field at Denver International Airport, injuring 37 people. No one was killed. In January, a US Airways jetliner landed in New York's Hudson River after a flock of geese disabled both its engines. All 155 people onboard survived. Last month, commuter plane fell on a house in a suburb of Buffalo, N.Y., killing all 49 passengers and a man in the home. Before the Buffalo crash there hadn't been an accident involving a commercial airliner in the US in which there were fatalities in more than two years.