Terrible Ski-lift failure in Georgia sends people flying into the air - Page 1
Forum section: electronics / general

author: OE2WHP
author_rank: Regular Contributor
timestamp: March 20, 2018, 10:24:03 am
content: “Jump, jump” that’s what people were screaming to warn skiers of trouble ahead. A ski lift malfunctioned at the Gudauri resort in the country of Georgia. People were forced to jump, others were thrown off their seats. At least eight people were injured, no one died. WARNING: some people may find this video disturbing.What really bugs me1. The guy woh is filming instead of doing anything helpful....2. Noone had the idea to push the emergency shut down button.3. Why the hell did the system not stop on its own?I mean, we don't have any details what the owner or the operators did to the system but maybe they tampered with the security systems of the lift.I am pretty sure that the manufacturer of this lift, a company from my home country (https://www.doppelmayr.com/en/), one of the most reknown manufacturers of ski-lifts would have some failure detection emergency shutdown system. They know their stuff.Also, it is the first accident of this kind that I am aware ofWhat could have gone wrong to make the lift go into "fast rewind mode"??

author: The Soulman
author_rank: Super Contributor
timestamp: March 20, 2018, 10:39:15 am
content: Only speculating as I don't know the construction of these lifts.If the large wheel is driven from a chain coupled to the motor/reduction-box to createadditional gear reduction (small sprocket to large sprocket, not unlikely) and the brakes are only at the back of motor (easier to manage).Then if the chain would break (they do require maintenance..) the weight of the passengers alonegood make it spin this fast.What ever the cause, a sad event either way.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 20, 2018, 10:41:38 am
content: You see people getting mad about other people not helping regularly, but often it's a matter of not being able to do much. Getting hurt isnt helping anyone and other than pulling people away from the lift, there's not much that can be done. If you don't know what to do, it's best to simply stay out of the way.My information is far from reliable, but I've heard the lift lost power. This meant the lift started moving backwards due to the weight of the people in it, with the result you see. Judging by how the lift did stop in the end, someone did push the emergency brake. It seems a few people were actively trying to figure out how to do that, as the guy dressed in red walking into the shot at 0:32 is clearly trying to communicate with someone about what to do.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: March 20, 2018, 10:41:55 am
content: Quote from: OE2WHP on March 20, 2018, 10:24:03 amRecording an incident like this can be very useful for investigating what happenned.

author: apelly
author_rank: Unknown
timestamp: March 20, 2018, 10:59:33 am
content: Quote from: mikeselectricstuff on March 20, 2018, 10:41:55 amThe journalist's demeanour.Edit:Shit. I meant dilemma

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 20, 2018, 11:09:06 am
content: Quote from: apelly on March 20, 2018, 10:59:33 amNot really. You don't want an incident happening, but you certainly don't want an incident to happen again.

author: fubar.gr
author_rank: Unknown
timestamp: March 20, 2018, 11:15:04 am
content: Quote from: mikeselectricstuff on March 20, 2018, 10:41:55 amThis.Besides there's little a random passer-by could do to help.

author: mdijkens
author_rank: Regular Contributor
timestamp: March 20, 2018, 11:16:46 am
content: I can imagine pushing an electronic emergency button doesn't do much when the chain broke and the whole system is freewheeling?From the footage it is clear the lift is running on gravity of the people still in it; that's why it stops in the end

author: Muttley Snickers
author_rank: Unknown
timestamp: March 20, 2018, 11:42:14 am
content: The same event from another angle, in this one it appears that the camera man is in fact a hero, seems he was the one yelling at people to jump and he also assisted somebody who was stuck in the debris.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 20, 2018, 11:46:13 am
content: It's also worth remembering that tugging on people who just were in a traumatic event can make things worse, much worse. When there's the potential of skull or spinal injuries, you need to be careful.

author: hs3
author_rank: Regular Contributor
timestamp: March 20, 2018, 12:08:12 pm
content: Quote from: OE2WHP on March 20, 2018, 10:24:03 amI didn't actually watch the videos so this is just a general comment. But there days many skiers may have an action camera attached to their helmets and already filming. So to film something like this it can be enough to just be in the area and be looking in that direction.QuoteMy guess would be that the lift was freewheeling and for some reason there was a brake failure. I'd imagine that this kind system should have automatic brakes for this kind situation but those weren't working for some reason.

author: OE2WHP
author_rank: Regular Contributor
timestamp: March 20, 2018, 12:12:02 pm
content: Quote from: mdijkens on March 20, 2018, 11:16:46 amGood point, but isn't that a failure mode that should be pretty obvious and be chatched during FMEA?

author: mdijkens
author_rank: Regular Contributor
timestamp: March 20, 2018, 12:15:22 pm
content: Yes, so probably the red button just (only) stops/blocks the motorI assume these systems have an independant mechanical auto-brake system (which failed obviously)

author: apelly
author_rank: Unknown
timestamp: March 20, 2018, 12:21:58 pm
content: It's too late for me not to look like a goose... But I mistyped earlier.It's the journalist's dilemma. Get involved, or report the story. I understand it's a particular issue for cameramen. I don't know what their code of conduct says about it, maybe there's one hanging around who could chime in.Also, obviously, not everyone with a camera is an actual journalist...

author: Zero999
author_rank: Super Contributor
timestamp: March 20, 2018, 12:23:22 pm
content: Quote from: Mr. Scram on March 20, 2018, 10:41:38 amI agree.QuoteThere should be a brake, which activates when the power is lost. That's pretty standard on any system which can keep moving and present a hazard, due to power failure.

author: Jeroen3
author_rank: Super Contributor
timestamp: March 20, 2018, 01:09:03 pm
content: Quote from: Mr. Scram on March 20, 2018, 11:46:13 amHaving other people land on them isn't ideal either. In this case just pick the least worse.Cable cars often have the motor at the top, the bottom station might have been meaningless in this situation.Looking at the lack of significant building, it might have been the case here.https://www.doppelmayr.com/en/components/custom-drive-solutions/

author: Lord of nothing
author_rank: Super Contributor
timestamp: March 20, 2018, 04:40:45 pm
content: I dont know where I was read about that in the Lift System the have some Anti Tamper thing include to prevent it from Copy it.So some people say that the Company would safe cost and try to repair and maintain there stuff there own and some anti tamper thing was kicking in. To get the Lift back to work the might have do some Russian style stuff to get it run and that used an go arround of some safety stuff.

author: The Soulman
author_rank: Super Contributor
timestamp: March 20, 2018, 04:49:50 pm
content: This is on the manuacturers site:Quotehttp://newsroom.doppelmayr.com/en/doppelmayr/news/accident-gudauri-georgia-friday-16-3-2018/

author: Electro Detective
author_rank: Super Contributor
timestamp: March 20, 2018, 11:46:50 pm
content: Can someone with a Youtube account please contactAvEto look into itso we can find out what really went wrongbefore it gets forgotten or swept under the snow

author: tooki
author_rank: Super Contributor
timestamp: March 21, 2018, 09:44:58 pm
content: Quote from: OE2WHP on March 20, 2018, 10:24:03 am1. What’s he supposed to do, exactly? And why him and not the dozens of other bystanders?2. What makes you think nobody thought to do that? The thing was goingbackwards, because the motor that drives it forwards was clearly either off or mechanically disconnected, AND the braking mechanism obviously failed.3. Why the emergency braking system failed is, of course, the million dollar question.

author: The Soulman
author_rank: Super Contributor
timestamp: March 23, 2018, 09:18:18 pm
content: Long story short, operator error. (preliminar result from investigation).http://www.economy.ge/index.php?page=news&nw=645&s=preskonferencia-gudauris-incidentis-shesaxeb-biuro-veritasis-pirvelad-daskvnaze&lang=enQuote

author: Muttley Snickers
author_rank: Unknown
timestamp: March 23, 2018, 09:59:59 pm
content: They can deem this failure as operator error all they want but where on a power outage people are openly put at risk and a sole person is then required to conduct a possibly non routine or rarely practiced sequence to start and switch over to generator power I would deem a serious design flaw or engineering failure.They should have incorporated some type of fail safe mechanism into the design to remove any risk of a runaway where on a power outage a mechanical braking system would be engaged perhaps with a manual lever to permit a controlled evacuation of people, elevators incorporate such mechanical braking systems why didn't this dangerous chair lift ?.

author: Electro Detective
author_rank: Super Contributor
timestamp: March 23, 2018, 10:26:20 pm
content: How hard can it be?Power drops out,big relay drops out,no power,everyone inmodeSomeone restarts the machine or calls for rescueToo easy...

author: Lord of nothing
author_rank: Super Contributor
timestamp: March 23, 2018, 10:36:27 pm
content: I heard enough Story about people who are bad or non trained.The get told "push here for Start and Stop and if something happened here is a flyer what to do."

author: OE2WHP
author_rank: Regular Contributor
timestamp: March 23, 2018, 11:01:52 pm
content: Doesn't sound plausible to me. Sounds more like a pawn sacrifice. These lifts do not go into free spin, taking lifes at risk when power drops out. They wouldn't even get an operating license here if this would be the case. I still think someone tampered with some sort of security mechanism.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 24, 2018, 01:17:15 am
content: Quote from: blueskull on March 24, 2018, 01:04:37 amThat's unlikely due to an independent investigatory bureau being involved. You could argue the manufacturer Doppelmayr is served by sweeping a problem under the rug, but the customer's trust is very important for a lift manufacturer and if people smell a cover-up it could seriously hurt the business. Customers aren't stupid and it's better to have a good explanation that doesn't have a funny smell, even it it means admitting there's been a technical error. Not to mention it's a Austrian - Swiss company, people known for their tendency to be thorough.

author: Mr. Scram
author_rank: Super Contributor
timestamp: March 24, 2018, 02:33:23 am
content: Quote from: blueskull on March 24, 2018, 01:37:08 amThat's all possible, yet the involvement of both an independent bureau and the manufacturer make it unlikely that will fly. Doppelmayr probably couldn't care less about the company that runs or maintains the lift. It just needs to the world to know their lifts are safe. The same applies to the bureau. If you let someone dictate the outcome of your investigation, your days as an independent bureau are over.

author: glarsson
author_rank: Frequent Contributor
timestamp: March 24, 2018, 11:36:38 am
content: This is crazy.If the switchover from a failed mains to diesel backup requires a sequence of manual steps then this sequence should be interlocked in such a way that a catastrophic failure like this should be impossible from a simple misstake.Furthermore, a independent failsafe mechanism should be present that gauges the speed/direction and applies an emergency brake if outside of limits. This could be a simple centrifugal device that releases a spring loaded brake. Automatic brakes like this could be mounted in many (or all) towers to help with cable breaks, damaged towers and other failure modes.

author: Edison
author_rank: Frequent Contributor
timestamp: March 24, 2018, 03:55:02 pm
content: listen to the sound of the video, roll gears as if without resistance and accelerating. It means that the gearbox is separated from the engine (or the engine is off-duty and has a light-weight running), the reverse thrust is still accelerating. In my opinion, the safety brake did not work - like the elevator -unbraked engine brake jaw closed, the engine's servo jaw brake opens when the engine is energized.