The chief executive of Six Flags says the company will install seat belts on the Georgia roller coaster from which a rider fell to his death earlier this month. The company’s rides with similar restraints will also get the safety upgrade.
The theme park operator announced the extra safeguard less than two weeks after 42-year-old Hassan Jihad Ibn Kariem of Atlanta died after being ejected from his seat on the Goliath coaster at Six Flags Over Georgia.
The original design of those particular restraints has 4 separate pawls that engage with the ratchet holding down the restraint, any one of them is more than capable of holding the full force of even the largest rider. The newer versions are purportedly half ratcheting half hydraulic, but that’s not what was present on the Goliath in question.
The unlocking mechanism works on the entire row at once, so since it was just the one seat it’s probably not related to that.
B&M, the Swiss manufacturer also has notably not suggested any other customers close their similar rides pending investigation.
All that’s fine. But, the point is redundancy. It’s not about the safety factor of an individual restraint. You can have the strongest and most reliable safety mechanism; you still design safety around having multiple independent points of failure.
The “seat belt” is a restraint that is not doing anything 99.999% of the time. For some people, that might seem like a “unnecessary” part as the comment I was replying to stated.
But that’s the entire point. And a secondary form of restraint that is independent is the entire point. I just wish someone didn’t have to die before that happened.
What the corporations talking heads decide is “necessary” is not what I’m talking about. I’m talking about safety from the perspective of an engineer.
I use to work in power systems and designed redundant power supply arrays. For some customers, like hospitals, they don’t just factor in a “n+1” (n active with 1 redundant) redundancy. They require a “n+m” (often with m>n) redundancy because of the critical operation of their power infrastructure. Because operating standards and regulations force them into maintaining this level redundancy.
Meaning, an array of power supplies that needed 4 power supplies to operate would have 4 or more additional redundant power supplies doing “nothing” most of the time. Because you don’t design around “the average day”. You design systems like this around “the worst possible day”.
So, when the dumb guy that plugs in the wrong power cable, ignores the flashing lights, burns a power supply, and then thinks “hmmm not working, let me try plugging it into another one.” When that dumb guy comes around. People in the hospital have the best chance of survival.
Right what I’m saying is internally it is 4x redundant and is designed to fail safe regardless.
Here’s an old (2006) publicly available version of ASTM F2291 which governs amusement ride safety, notably class 5 restraints (highest tier) must be either redundant (i.e. two distinct devices as you suggest, or fail safe) and have external verification, which in the case for these ones is a proximity sensor that gets flagged once the pawls have dropped in by enough teeth