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.


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.
  • 1
    $\begingroup$ +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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