The Texas Giant roller coaster remained closed Sunday, as investigators continue to look into what may have caused the death of a Dallas woman on Friday.
Witnesses said 52-year-old Rosy Esparza had expressed concern to ride operators about the security of her lap bar, but was still allowed to ride.
It was Esparza's first time at Six Flags, riding the roller coaster with her son, when she suddenly fell to her death from the ride.
"When it dropped to come down, that's when it released," said Carmen Brown, who witnessed Esparza's fall. "She just tumbled."
The ride was redesigned just two years ago, and according to Six Flags' website, it has two wooden roller coaster records: the steepest drop, and a bank that turns riders at a 95 degree angle.
Walter Reiss has more than 25 years of experience in inspecting amusement park rides and said that the intensity of the rise raises questions for him about the types of restraints used.
"Normally when you start getting to these speeds and angles, you go to a shoulder restraint," Reiss said. "That kind of throws me a little bit."
Witnesses said Esparza expressed concern to operators about her lap bar only making one click. If true, that is a red flag for Reiss.
"If it only made one click, that tells me, as an inspector, that you're at the threshold and that this lap bar is not even engaging at all," he said. "If a person cannot fit properly, they need to be told as diplomatically as possible that it would be safer if they don't ride."
That rule of thumb applies to riders who are both too large and too small for the ride.
"They have got height restrictions to prevent smaller children and that's because the harness is not designed for riders under X height, whatever that height is, based on the dynamics of the ride and what the manufactures recommend," Reiss said.
But Reiss added that the threshold is ultimately enforced by ride operators.
"Every patron depends on the park and their representatives to tell them, ‘look you cannot do this,'" he said. "If in fact she was too large for this particular seat--and it's kind of a tight seat--than in my opinion, I don't think she should have been allowed to ride for safety reasons."
Whether or not those restraints in fact played a role is still under investigation.
In a statement, Six Flags said, "We are committed to determining the cause of this tragic accident…It would be a disservice to the family to speculate regarding what transpired."
A team of roller coaster engineers from Germany are also being sent to Arlington to inspect the ride.
Copyright 2013 KLTV. All rights reserved.