From: ISO 9000 Standards Discussion <
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Date: Thu, 26 Oct 2000 10:38:44 -0500
Subject: Re: Firestone /../Hellmann/Pfrang/Daniels
From: "Daniels, Beverly" <
[email protected]>
Without answering the "should the registrar have detected the problem and rescinded Firestone's QS registration" argument, I do want to address Doug Pfrang's comments about the "low" defect level and the "customer abuse".
Doug wrote:
> Finally, keep in mind that the number of customer complaints
> that triggered Firestone's recall is less than 0.01% of the
> 6.5 million tires that Firestone has agreed to replace, and
> the latter is only a small fraction of the total number of
> tires that Firestone currently has on the road.
Yes this seems like a small number (it's ~ 100 ppm). However, I'd like to calibrate us all on what constitutes a small number in the auto industry (and many other industries) and how these numbers are really larger than we might think.
First: 100 ppm is too large per QS9000 requirements for critical characteristics. They are very tight about this in their specification of Cpk/Ppk requirements.
But more to the point a .01% failure rate in a product grouping (and this is how it's looked at not by looking at the failure rate for the entire product line...) is considered very large in automotive, particularly for the kind of failures (catastrophic product failure and death). Look at eh
FMEA forms: they REQUIRE preventive action for any "10" in severity of effect, which means that the failure will be unannounced, the effect unavoidable and a serious safety "occurrence" inevitable should the failure occur. And this requirement for action on a 10 is regardless of probably occurrence level! so the generally accepted practice in the automotive industry is that this .01% is too large. Now, reasonable people know that it's really possible that this failure mode "may" have been "unknown" in any FMEA, but good quality, business or ethical understandings should have led Firestone to taking immediate corrective action to PREVENT the reoccurrence of the failure in future product once the field failure rate was known. And, yes in my time in the automotive industry (and others) I worked on many such low defect / rate high severity issues to correct them. It was an imperative to save lives and save the company from the inevitable litigation and legislative actions if we didn't correct the issues.
Also, having studied automotive/consumer warranty for a long time, the actual number of failures is always under-reported by the user and under accepted by the manufacturer...the actual numbers of failures is in all likelihood far higher than .01% - or whatever number is being bandied around today. Especially with tires which have very daunting rules about warranty. They are set up to under report.
Another point inside this one: Mr. Pfrang states that there is only one vehicle that is overwhelmingly involved and this is not completely true (as far as I can tell from all of the public reports). First off it appears that the Explorer is the largest (by far) user of these tires so they would have the largest amount of failures. Secondly it does sound as if there is an interaction between the tires and something with the Explorer that could be making the occurrence rate with the Explorer higher than with other vehicles...certainly the Explorers high center of gravity would make the vehicle more likely to roll when the tire blows (it' a very violent event) So that the Explorer would experience more deaths per tire failure than other vehicles that have a lower tendency to roll. This phenomenon would also lead to a relative under reporting of the tire failure for those vehicles that did not roll and hence did not experience any human damage. (The Ford truck sites, by the way are full of stories of Ford TRUCKS experiencing the tire blowout but not the rolling/death consequence...) Now, of course my "reporting" here is based on publicly available data - if one knows where to look - and that is not the whole truth, nor even the truth in many cases. The point to learn here is that until the lawsuits are settled the true "reported to the entities involved" numbers will be a large matter of speculation. And the true number of incidents will never be known. But .01% is very large for this type of event.
Mr. Pfrang also states:
> Frankly, given the way many drivers abuse their tires --
> chronic underinflation, overloading, squealing tires away
> from stoplights and around corners, slamming on brakes,
> driving off-road, driving on pavement that can range from
> 35 degrees below zero to 160 degrees above, driving 80 mph
> and above (and slamming into potholes and road debris at
> those speeds), hitting curbs, hitting glass, etc. -- I'm
> amazed we don't see far more "premature" tire failures.
Well, this may be true. I hate those dang Customers. They never do what we tell them to do with our product, do they?? The world would be a better place without them! They are the root of all evil and should be shot on sight!!
All sarcasm aside: that's the market boys! and the automotive industry knows it. And MOST products prepare for it. The smart ones do it consistently. The dumb ones lose market share and go out of business. The Customer today expects more and more. They want the product to withstand what they "reasonably" will do with it...and the conditions that are listed above are reasonable. Maybe on the harsh end of reasonable...but still reasonable. And quite a few of the examples are unavoidable conditions of the driving environment in the US and the world...AND my SUV better be able to drive off road - that's what I bought it to do and that's what it's advertised to do and by golly it better do it for the money I paid for it!
Sorry Doug, the above is not abuse. Only those who want to tell the customer the exact conditions of use of their product think that. And they are in severe denial. The vast majority of the auto industry knows it's a fact of life. They may not like it, they may complain about it, but they DO design and manufacture their product to perform in that kind of environment. Cause if they don't - someone else will.
And more to the point: From what has been reported: NONE of the stated conditions above would lead to the type of failure the Firestone are experiencing. (Driving long distances at highway speeds - not an unreasonable expectation - may make the failure occur earlier, but it would still occur). It is an internal manufacturing defect that takes time (actually use) to finally fail. But it's not the use that causes the failure; that's normal and expected environmental stress. It's the manufacturing defect that causes the failure.
Bev Daniels