CARRABASSETT VALLEY, Maine — An automatic braking systems did not deploy when a mechanical failure caused the rollback on the King Pine chairlift at Sugarloaf, according to preliminary findings of an investigation into the accident released Sunday evening.
Three people were sent to the hospital and four others were treated at the scene when the accident happened around 11:30 a.m. Saturday, causing the chairs on the lift to travel backward a distance of nine chairs, according to Ethan Austin, Sugarloaf spokesman.
A lift attendant was able to apply an emergency caliper brake that slowed and ultimately stopped the rollback, Austin said.
The preliminary findings showed the initial mechanical failure was in one of the two gearboxes that connects the lift’s electric motor to the drive bullwheel — the large metal wheel around which the cable supporting the chairs revolves, Austin said.
That failure decoupled the bullwheel from the lift’s primary brake on the driveshaft and from the anti-reverse brake, which is the first of three redundant mechanisms to prevent a rollback, he said.
The final braking mechanism, known as a “drop dog” — a large metal pin that drops into the bullwheel to prevent rotation — apparently failed to deploy as designed.
The application of the emergency brake by the lift attendant likely prevented a more extensive rollback, Austin said.
“The cause of the gearbox failure and the failure of the drop dog to deploy as designed both remain under investigation,” Austin, said. “It is likely that determining the root cause of these failures will require extensive analysis.”
The investigation by Sugarloaf staff and an engineer from Maine Board of Elevators and Tramways into the cause of the accident began shortly after the ski patrol evacuated 203 people from the crippled lift, Austin said.
Lift mechanics routinely check gearbox oil levels as part of their daily pre-operating checklist, Austin said.
On the day before the accident the faulty gearbox, which had a major overhaul at the start of the 2011-2012 season, passed a sophisticated routine preventive maintenance procedure intended to identify potential problems, he said.
But much like an automobile transmission, he said, the machinery inside of a lift gearbox is not easily observed, so Sugarloaf contracts for routine maintenance tests that can indicate any potential problems, he said.
Those tests include oil and vibration analysis, which were conducted on the King Pine lift on Jan. 19 and March 20, respectively, Austin said, by outside contractors. No irregularities were found.
The King Pine lift was certified to operate by the tramway board on Oct. 29, 2014, after its annual inspection and a full dynamic load test, according to Austin.
“Our first concern remains with those who were injured, and those who went through a truly frightening experience,” Austin said. “Based on what we know now, we’re grateful that this situation wasn’t any worse.”
Immediately after the lift’s failure on Saturday, people at Sugarloaf took to social media to describe the lift suddenly rolling backward and skiers having to jump off as it picked up speed.
“I was waiting in line to get on the lift,” Darrell Davis of Kennebunk said late Saturday afternoon. “It was really confusing, and the first thing I saw was this kid who I knew had just gotten on the lift but he was just standing there.”
Davis, 48, said he soon realized the chairs on the lift were traveling backward with skiers on them.
“I saw a chair go around the back end of the [lift’s] wheel, and it was just flying up in the air with people on it,” he said. “People were jumping off, and it seemed to go on for a long time.”
Davis described a chaotic scene of people leaping from the moving chairs as crowds on the ground yelled for them to jump.
“There was one chair where everyone on it had bailed, but this one kid who was still on it and just looking around,” Davis said. “We are yelling, ‘For God’s sake, get off the chair!’ and for him to jump off so he wouldn’t go through the lift’s superstructure and fly around that wheel.”
Davis, who was staying at Sugarloaf in a friend’s condo over the weekend, said he knew his son was skiing off the King Pine lift, and Davis suffered some anxious moments before the 16-year-old contacted him saying he was not on it at the time of the accident.
Davis said he has no idea what went wrong to cause the lift to go backward like that, but he speculated several mechanical devices and safety features must have failed.
Sugarloaf spokeswoman Noelle Tuttle said Saturday that this was the first time a rollback had occurred at the ski facility.
The King Pine lift is a 122 four-passenger chairlift that was built in 1988 by Borvig and capable of moving 2,100 skiers per hour, according to Austin.
“It’s too soon to say what, if any, changes to operational protocols will be made,” Austin said. “Part of that determination will hinge upon what’s revealed by the next stages of the investigation.”
Austin said the lift will remain closed pending further investigation.
In 2010, at least eight people — three of them children — were injured at Sugarloaf when a cable that lift chairs were attached to derailed and sent five of those chairs crashing to the ground. Dozens of skiers had to be rescued from the crippled lift by ski patrol units.
