HELENA — Just before a plane carrying 14 people crashed short of a southwestern Montana runway last year, killing everybody on board, the pilot told air traffic controllers that he had "one more cloud to get around" before he could reach the Butte airport.
A minute later, pilot Buddy Summerfield reported that the airport was in sight. That was his last transmission before witnesses saw the single engine turboprop bank left, then suddenly nosedive into a cemetery near the airport.
Questions arise about the plane
New details emerged Friday in the investigation of the March 22, 2009, crash of the privately owned Pilatus PC-12/45, raising questions about fuel pressure, icing in the area and whether the plane was over its weight limit.
The National Transportation Safety Board has not concluded what caused the crash. The agency says a determination of probable cause will be made when the final report is completed, and no date has been set for that report.
13 people on plane designed for 10
The plane designed to carry 10 people had been carrying 13 family members and the pilot from California to a ski vacation in Bozeman. A half-hour before the crash, Summerfield requested a diversion to Butte for reasons unexplained.
The NTSB docket into the crash released Friday contains interviews, air traffic control transcripts, investigator reports and other documents that the agency has collected so far in its probe. But the agency provided no analysis for the information laid out in the documents and said it would not give interviews to discuss them.
However, the reams of accumulated paperwork offer new insights into what happened that day and the final minutes leading to the crash:
• The plane appeared to have experienced fuel pressure problems for at least part of the flight, with its fuel boost pumps working to stabilize fuel levels between the right tank and the left tank.
• A low-fuel warning for one of the plane's tanks lit up six minutes before the crash.
• The flight plan called for nine people aboard the 10-seater plane, but 14 people were actually on the flight. That created a total weight that was 572 pounds over the limit when the plane took off from Oroville, Calif. However, one of the plane's owners told investigators the weight aboard the plane was not a concern.
• Icing and turbulence had been reported by another plane flying the same route that day. Before taking off, Summerfield did not request a fuel additive that would prevent icing in the fuel system, which is required in ambient temperatures below freezing. The ground temperature that day was 45 degrees and an approaching cold front was influencing the weather in the area.
The NTSB reports also say Summerfield asked air traffic controllers twice to clear him to fly at lower altitudes. That descent may be significant because of a checklist in the Pilatus PC-12 pilot's operating handbook that instructs the pilot to descend to warmer air in case of low fuel pressure.