Re: Root Cause Analysis

From: Chuck Ferriday (
Date: Fri Feb 07 2003 - 21:31:18 EST

  • Next message: Tony Planinac: "Re: AIR FORCE IMAGERY CONFIRMS COLUMBIA WING DAMAGED updated"'re saying that it is going to be necessary
    to stair step further down the causal chain until
    effective responsibility can be determined
    A tile, inanimate object that it is, will not be a root
    cause.  "HOLD THE TILE ACCOUNTABLE"  ?????
    No.....he who designed and he who approved
    are the feet at which responsibility can be laid....
    but not at the foot of a tile.
    And it is not necessarily that the tile was the cheaper.
    Least cost choice may be involved, but if another
    design offered more strength, more resiliency, better
    heat deflection......and if it cost more, then was the
    choice of tiles a problem with engineering cost
    management vs the value of human lives?
    chuck ferriday
    ----- Original Message -----
    From: "Pinizzotto,Russell" <>
    To: <>
    Sent: Friday, February 07, 2003 3:10 PM
    Subject: Root Cause Analysis
    > Having been involved with failure analysis, I would agree with Markus that
    > one piece is probably not THE root cause.  In cases like this one, there
    > usually a chain of events and causes that haven't been thought about very
    > much that cascade into a catastrophe.  For example, the O-ring in the
    > Challenger case is not THE root cause, it was a combination of weather,
    > design, poor choice of materials and cutting some corners.  Remember, the
    > joint was totally re-designed after that incident and not just to change
    > O-ring configuration.
    > I expect that when the Columbia failure is finally understood, it will be
    > similar chain of events.  For example and totally hypothetically, a chain
    > events being foam coming off the ET, damaging one tile, which led to
    > cracking of one carbon-carbon composite piece in the leading edge during
    > re-entry which caused something else to disrupt the whole leading edge
    > led to failure of the entire wing assembly.
    > A good example is the Turkish DC-10 crash of about two decades ago.  A
    > technician moved the safety locking pin so the baggage door could be
    > more easily.  That resulted in being able to close the latch handle when
    > actual latch was not positioned properly.  There was a design problem with
    > the closing mechanism, but if the pin had been left alone, it would have
    > been noticed.  Was the root cause the pin, the technician, the latch, of
    > unfortunate combination of all of the above?
    > Best Regards,
    > Russ Pinizzotto
    > +
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