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I was reading about how we reused the water tanks because they were still within their certified life-time and had two questions:

  • When would a certification become VOID?
    • I'd assume if the water tanks accidentally took a fall they'd not be certified still.
    • What are some other examples of events that can void a certification?
  • When an event occurs altering the suitability of flight hardware how is it re-certified?
    • I'd assume there's some sort of inspection, could someone outline what it'd be?
    • You may use the example of the water tanks being dropped, what would NASA do?

You may also consider the toppled NOA satellite as a case study too if you wish. I'd like to know what all they had to do to consider it as "certified" again after the incident.

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From what I've observed, the general process works like this:

  1. A Non-Conformance Report (NCR) is generated. These are applicable for everything from an unexpected scratch or tool mark on a surface to a system-level failure. The NCR identifies the "is" vs. "should be" state of a component.

  2. A Material Review Board (MRB) convenes. This is a group of engineers and managers who make decisions in a structured way regarding NCRs. From here, it's case-dependent. It may involve specific analysis, or it may just be a series of discussions. It all depends on the specific nonconformance.

  3. The NCR is dispositioned. Again, case dependent. The disposition is determined by the MRB. Typical disposition outcomes:

    • Use as is. Analysis shows the nonconformance does not affect safety or mission success -- no corrective action is necessary to certify the part for flight.
    • Rework the part. Case dependent. Could be as simple as redrilling a hole in the right location, buffing out scratches, etc.
    • Use as is, issue drawing rev. In the case of a misdrilled hole, for example, create a drawing rev showing where the hole was drilled so that there is traceability between the drawing and what was manufactured.
    • Scrap. The component is too far gone. Toss it out and build a new one. Depending on the source of the NCR, it may be a build to print, or there may be a redesign.
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    $\begingroup$ +1, A couple of things to add: A) the MRB is usually given total authority over the future of the part and may direct the project office to examine, test, repair etc. B) there is usually a distinction drawn between "re-work" such as your first example and "repair" which is closer to your second example of buffing to remove a scratch. The difference lies in that "re-work" is re-application of the same processes used in the original build whereas "repair" uses additional (authorised) processes that were not needed for an original build. $\endgroup$
    – Puffin
    May 30 '19 at 23:01
  • $\begingroup$ Thanks for taking the time to answer! $\endgroup$ Jun 1 '19 at 4:01

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