HELENA — The pilot of a single-engine plane that crashed and killed 14 people in Butte in 2009 cut safety corners and then did not take the appropriate action after discovering a problem with his fuel system, the National Transportation Safety Board concluded Tuesday.
The privately owned plane carrying seven children and seven adults from California to a ski vacation in Bozeman crashed moments after the pilot requested a diversion to Butte without explanation.
The board's findings of probable cause lay the blame on the 65-year-old pilot, Buddy Summerfield, who had 44 years of flying experience and never had an accident or a violation before the crash. The former Air Force pilot had flown the plane owned by Eagle Cap Leasing of Wallowa, Ore., since 2002. He had made one previous flight from Oroville to Bozeman the year before.
The pilot "appeared to be cutting corners in a lot of areas," possibly the result of years of being the only pilot involved in an operation with no oversight, NTSB investigator Malcolm Brenner said.
Summerfield didn't add ice inhibitor to the Pilatus PC-12/45's fuel as required when flying in freezing temperatures.
The ice inhibitor would have prevented ice crystals from gumming up the plane's fuel system, which was the start of the problems on that final flight, the NTSB concluded.
Then, when a fuel problem became evident during the flight, the pilot should have immediately landed at the nearest airfield. Instead, he appeared to believe at first that it was "a gremlin that would probably work itself out," Brenner said.
The pilot may not have wanted to inconvenience his passengers by diverting from the flight plan, Brenner told the board.
"It appears he's taking short cuts in terms of strict safety compliance to favor the clients," he said. "Beyond that, it's difficult to understand just what his dynamics were."
When he requested the emergency diversion to Butte, Summerfield couldn't handle the weight difference and lost control as he tried to land, resulting in the fiery crash that left no survivors, the NTSB concluded.
Brenner and other investigators said Summerfield's short cuts began before the plane even took off. There were too many passengers and too much weight on board for that type of plane, though neither of those were factors in the crash, the NTSB concluded.
The pilot should have noticed the fuel problem long before he requested the diversion to Butte, investigators said. The disparity between the two tanks would have been evident on the fuel gauge, and data recovered showed that Summerfield manually toggled a pump to try to fix the problem.
The proper course of action in that case is to land the plane immediately, investigators said.
But he didn't, even though he passed over four airports in Idaho and southwestern Montana after the problem was obvious.
"The pilot should have landed at the first opportunity after he realized he couldn't balance the fuel load," investigator Thomas Little said.
Witnesses on the ground said the plane approached the Butte airport higher than other planes normally do — at about 3,550 feet less than two miles from the runway.
The witnesses reported seeing the plane make a sharp left turn, then enter a steep bank and pitch downward, Little said.
Investigators concluded that the plane was controllable even with the heavy left wing, but the weight disparity must have taken the pilot by surprise. They said he ended up exacerbating the plane's roll instead of correcting it.
For the past two years, investigators have been trying to piece together what happened. They didn't have a lot to work with: no survivors, no flight recorder and little that survived the impact and flames.
But in a break, they were able to recover undamaged chips from a computer system and spent months decoding their data. Only then did they begin to understand that a fuel imbalance problem brought on by ice in the fuel system was the root cause of the problem.
The NTSB recommended that placards be placed on planes in which ice inhibitors are required that remind pilots of that fact. Investigators also suggested installing flight recorders on small planes, saying the probe would have ended a lot sooner if there had been one on board.
Even though the report said the extra passengers were not a factor in the crash, the NTSB said there should be just one passenger per seatbelt on board any plane.