I've had a look at Al Wicks approach and for me it leaves a lot of unanswered questions. I have the benefit of being a ( now retired) Government Logistics manager, trained in Quality Assurance,  Occupational Health and Safety, Risk management and of course procurement. I had a good deal of experience within the medical logistics field.

This basic approach gives a basic guide provided you get your facts straight and work on with the right information - I can't see this being done with the Rotary. Perhaps he has done quite well with the Subaru - who would know.

 

Al if your on here would you please elaborate on the statement on Aluminium - the information to me is that Hydrogen is indeed the major problem with non- injection cast aluminium. Especially if it involves elevated thin pour castings - the elevated temperature draws hydrogen from the air and releases it as bubbles in the aluminium, the higher the humidity the greater the chace of Hydrogen porosity.

As we all know porosity is the primary cause of strength reduction in a cast aluminium piece. I understand there are other causes of porosity, but am unsure of what they all are.

 

George ( down under)

Ernest Christley wrote:

Jim, Al is not following his own process (I think I alluded to this previously). First, you have to ask, "How many failures have accurred due to a faulty CAS?"  That's a fair question.  Do you know?  Does anyone?  If so, Who?  Seems there was a thread around that just a month or two ago.   Intuitively, I would say that CAS would be a single point of failure, important enough to be remediated.  The text below is copy and pasted from  http://www.maddyhome.com/canardpages/pages/alwick/risk.html The key phrase is the last sentence.

We are going to do an FMEA. What is the goal we are trying to achieve with this process? It’s to make sure we place our efforts on the facets which need it. Put another way, it’s making sure we don’t waste time and effort on insignificant items, while ignoring the truly important items.

There are only three pieces to the puzzle.   In the case of CAS (just my guess)

1) If the component failed, how serious would that effect the airplane?  catastrophic

2) What is the probability of the component failing? Undetermined.  Start with doing some research at NAPA et al and repair shops around how many they sell.

3) What is the likelihood that you would notice the problem before failure?  I'd guess very VERY remote.

You may have heard statements like “You have to replace component x on your engine before installing into an airplane because it represents a single point failure”. Meaning that if x fails, there is no backup component. That statement is not meaningful until you assess all three questions above.
Exactly.  Al's question is "... to what extent are "we" using his methodology.  My own guess would be "not much ...".  Single point(s) of failure in Tracy's ignition (and fuel control) systems - if there are any - would be a case in point.  As would redundant fuel pumps powered by a single source, and charging systems that are not sufficiently redundant and with appropriate indicators.  If one DOES have a single point of failure (and there are inevitably many) we must be sure that that component is sufficiently robust to give us all confidence that it will NOT fail.

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