Ladder collapses in Arizona

[Chief_Roy]

http://www.firehouse.com/news/108878...-aerial-mishap

Has anyone else been following this story? The investigation said that two cables snapped due to severe wear on the pulleys. The truck was two years old and had been used on only one fire in that period of time.

I was never an engineer, but I certainly worked on a lot of aerials over the years. The first being a late 50s/early 60's model LaFrance that was still a workhorse. It strikes me as odd that a two year old Sutphen (that was admittedly used very rarely) would suffer a catastrophic failure like this. Is this a "they just don't make 'em like they used to" sort of thing, or am I missing something in the bigger picture?

[firepundit]

As I read it, they cited lack of maintenance due to poor training and maintenance guidelines. Apparently, one hour of factory training isn't enough to learn operation and maintenance of an aerial platform. Who would have thunk?

The part about the fiberglass bushings kinda baffles me. I think the bushings most likely were UHMW plastic with graphite impregnation (Nylatron) but find it odd that it would be used as the bearing for a sheave. It seems like brass would have been a better choice.

The article also gave the impression that this is a recurring problem for the brand but I don't remember reading or hearing about the other incidents they mentioned.

[snowball]

I'm waiting for FIREMECH1 to chime in, but I will say this. We have had to replace the pulleys on several of our newer trucks due to excessive wear and improper adjustment. They have the UHMW plastic pulleys.

I could see a cable jumping out of a pulley and shock loading that platform causing that section to retract, especially under the extra load it had on it. Anyone who has been up a fully extended ladder has felt the little "bang" when you reach the end, that is a lot of stress on those cables and pulleys. The cables need adjustment periodically, all wire rope stretches, especially if it is stored under load like most ladder trucks are.

I hope the folks that were injured make a full recovery. It's unfortunate that their experience at a fire station will be remembered this way.

[ThNozzleman]

A lot of stress on those pullies. If both were locked up and the system was trying to drag dry cables around them for a while, I can see how they both snapped. I believe we had to replace sheaves, bushings, and pins on our Smeal/Ferrara unit a while back. Also, another good reason to keep civilians away from ladder trucks; these things aren't kiddy rides.

[nameless]

They said it only went to one fire, but the comment about public demonstrations makes me wonder how many times had the truck been used as a amusement ride. Ladder probably loaded at or beyond rated capacity and sent up and down for a few hours sounds like severe service.

[tree68]

Four people plus a firefighter at 200 Lbs each would put the bucket at it's (IIRC) rated load of 1000 Lbs.

Given the trend these days for folks to be carrying a little more weight, that puts the bucket over its rated capacity.

The truck was, what, three years old? Allowing for just routine weekly "exercise" of the ladder (some departments do it daily), it's been operated about 150 times, albeit minus the extra load. And that doesn't take into consideration the "public" events. If they weren't keeping things lubed and inspected, it's not really surprising that the pullies had deteriorated. And doubly so given the suggestion that they may have issues in the first place.

[SCOOBY14B]

There have been two cases (one in Arizona and one in Florida) that are similar, but two different models. BOTH cases were due to lack of maintenance. Doesn't matter the brand, if you don't maintain it...it will fail.