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HomeAircraftHelicopterHelicopter Main Discussion › Composite heli crash, walk away.
01-10-2015 12:36 AM  3 years agoPost 21
cdrking

rrElite Veteran

Seattle

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It appears that the helicopter industry accepts this type of failure possibility in their design.
Dave,

Why would you think the industry accepts this possibility?

I believe the manufacturers of all full scale helicopters would only accept parts that they have tested and/or have a proven design. Using a proven part on a different helicopter, one that it was not originally designed for, is another story.

Crazy video for sure.

Jeff

To hover is divine, the alternative is rather PLANE.

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01-10-2015 01:05 AM  3 years agoPost 22
dkshema

rrMaster

Cedar Rapids, IA

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What I stated is that the helicopter industry appears to accept that a single point failure of the swashplate scissors could lead to a catastrophic failure. Perhaps that's understandable as loss of a single pitch link can bring you down. And then there is the ubiquitous Jesus Bolt. We all know about it, and we all know WHY it's called the Jesus Bolt. But it exists, nevertheless, in full-scale helicopter design.

I didn't say they were willing to accept inferior parts, or use parts not suited to the design.

Third party parts does NOT mean inferior parts. It means the part was built by an approved supplier who met the requirements in the bid package.

It appears that the part failed due to a high number of stress cycles leading to fatigue and eventually breaking.

The question now should be WHY did it fail in such a manner? Is there something in the design of the helicopter that hasn't been properly accounted for? Was it properly assembled in the first place. Had it been damaged? Did the designer screw up? Was the design tested to failure before being declared flightworthy? Since the manufacturer claims they will now use a dual-redundant mechanism, how certain are they that the rood cause has been fixed?

As noted, there are at least two almost back to back AW109 failures on record, both having the same root cause---improper assembly of the bolt in the scissors, causing undue fatigue in very short order. And that single bolt failure led to the loss of two airframes, and injured some people.

-----
Dave

* Making the World Better -- One Helicopter at a time! *

Team Heliproz

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HomeAircraftHelicopterHelicopter Main Discussion › Composite heli crash, walk away.
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