Chairlift Detachment - Attitash Mountain Resort, NH, USA

[dold]

https://unofficialnetworks.com/2025/02/03/details-emerge-attitash-chairlift-detachment/
https://liftblog.com/2025/02/02/chair-falls-from-lift-at-attitash/

More of a maintenance and inspection failure, but interesting photo of the failed part. I'd be interested to hear some of the materials / mech folks' take on that.

Lots of blame going to Vail Resorts (for those not in the know - Vail is the evil megacorp that has bought up tons of small and large resorts across the US and other countries, then hit the "maximize profit" button) for deferred maintenance, lack of training, etc.

Some reports on facebook groups from skiers who were on the lift at the time of failure indicate that the lift faulted at least once and the lift operators kept resetting the faults without much ado.

This failed part is part of the mechanism that attaches / detaches the chair from the rope while going through the terminal, and otherwise holds the chair in place on the rope. Several lift maintenance folks online have said that the wear on the grip that you see is abnormal and indicates misalignment of the grip as it goes through the terminal. The failure surfaces are pretty apparent and pretty corroded. Wild that this was never caught in an inspection.

Interesting discussions on reddit too. Insight from lift operators and lift maintenance/inspection folks.

https://www.reddit.com/r/icecoast/comments/1igqgia/attitash_ski_lift_grip_that_fell

https://www.reddit.com/r/skiing/comments/1igr10p/attitash_ski_lift_grip_that_fell_on_22

Failed part (source: reddit). A more zoomed out photo would be nice.


Failed surface shown in red on full part. Not the exact same model of grip but similar. (source: reddit)



Chair as it lay. Guys is alive (source: liftblog https://liftblog.com/2025/02/02/chair-falls-from-lift-at-attitash/)

 

[ANE91]

Can someone draw me a big dumb arrow for the “apparent corrosion?” My eyes don’t see that.

 

[btrueblood]

The brown color of the fractured surfaces is assumed to be rust, as the material is assumed to be steel.

 

[DirteJoe]

From a magerial side, those pictures are too trash to determine anything other than she broke, and has ben broke for some time.

Is that cold galv or silver paint on it?

 

[Stick.]

Based on that photo alone, I wouldn't definitively conclude those 2 areas are corroded from a slowly progressing fracture, but that does appear to be a possibility. Really though, better pictures would be good to be more definitive.

I'm curious if the investigation will reveal this to be an actual engineering failure (too infrequent of an NDT frequency specified, poor design, improper material choice, etc), or an operation/organizational failure (poor training, culture that ignores potential safety problems, improper/no procedures for dealing with lift malfunctions, etc).

This Reddit comment from a lift mechanic (not at Attitash) indicates that these components typically have a serial number, so it will be interesting to see if there are any inspection records for this particular component that failed, or any of that component from other chairs/grips.

 

[Tomfh]

Wow, they snapped off. Sure looks like it's been progressing for a while.

 

[SWComposites]

Yeah, would like to see some close up photos of the fracture surfaces.

 

[ANE91]

Kinda looks like heat discoloration to me. Cyclic loads, cold air…wonder what the metallurgists would say.

 

[btrueblood]

"Kinda looks like heat discoloration to me. Cyclic loads, cold air…wonder what the metallurgists would say."

Hunh? It's a bog standard fatigue crack progression in a wet environment. Crack opens, water seeps in, rust happens, repeat for N cycles.

 

[Tomfh]

Pretty much.

 

[TugboatEng]

If it got hot enough to discolor the metal the paint would be charred as well.

 

[XR250]

How would it even get hot?

 

[DirteJoe]

If it got hot enough to discolor the metal the paint would be charred as well.

Unless the paint was applied after a repair.

How would it even get hot?

Weld repair.

"Kinda looks like heat discoloration to me. Cyclic loads, cold air…wonder what the metallurgists would say."

Hunh? It's a bog standard fatigue crack progression in a wet environment. Crack opens, water seeps in, rust happens, repeat for N cycles.

Ski-lift castings are quite often stainless. 17-4, 15-5, 304, and everyone's favourite crack-a-loy, Duplex 2205. You'd expect to see obvious pitting, not even discoloration from oxidizing. I doubt we're seeing rusting.

 

[XR250]

Unless the paint was applied after a repair.

Weld repair.


Ski-lift castings are quite often stainless. 17-4, 15-5, 304, and everyone's favourite crack-a-loy, Duplex 2205. You'd expect to see obvious pitting, not even discoloration from oxidizing. I doubt we're seeing rusting.

Weld repair? Seems like a risky repair on something this critical.

 

[SWComposites]

the thought of that failed part (a very critical part) being a casting gives me very cold shivers, as they can have all sort of defects and irregularities. hopefully it is not a casting.

 

[DirteJoe]

Weld repair? Seems like a risky repair on something this critical.

Yet it happens every day because engineer approved SOP's allow it within certain criteria. Can never discount what maintenance shops on site do as well. Weld repairs on critical castings can be done properly with no issues.

the thought of that failed part (a very critical part) being a casting gives me very cold shivers, as they can have all sort of defects and irregularities. hopefully it is not a casting.

It most definitely is a casting. I cannot imagine a machine shop would go out of their way to machine in a parting line mismatch and evidence of gates.

 

[IRstuff]

hopefully it is not a casting.

Having spent the last 3 weeks skiing and looking at the attachment structures, they are either cast or machined, but there are no obvious signs of machining, and the surfaces look like standard casting surfaces.

 

[Tomfh]

Having spent the last 3 weeks skiing and looking at the attachment structures

Normal people: “mmm, pretty mountains. I love skiing”

Engineers: “interesting. The stiffeners on the doppelmayr QF mark 2 are a revised geometry”

 

[IRstuff]

Normal people: “mmm, pretty mountains. I love skiing”

Engineers: “interesting. The stiffeners on the doppelmayr QF mark 2 are a revised geometry”

Yeah, my fellow riders are all-in deciding whether they want the safety bar down and I'm looking for signs of fracture or rust in the support arm Also checking out the attachment bolts

 

[TugboatEng]

Turbine blade are cast...