Present: M. Blaszkiewicz, L. Felsberger, N. Voumard
The meeting focused on the results of the probability estimations for asynchronous dump triggered by the TSU.
Before starting, the participants revisited the issue of the VPSOK signal stuck to TRUE. It was observed that only the 3.3V line could be problematic. Nonetheless, it also does not lead to specific end-effects, as there is a connection to the other TSU. On top of that, the missing the 3.3V line would cause many other elements to fail, eventually making the failure easily identifiable.
There are two potential causes identified in the FMECA:
The third possbility, asynchronous dump triggered via asynchronous path without triggering the synchronous dump was rulled out, as no relevant failure modes were found in the system. The model for the estimation of the 1st option likelihood and data found for the 2nd option were further discussed.
The high failure rate of fuses (20 FITS each) got some of attention; the high number is caused by the lack of more concrete estimations from newer sources than another study completed sometime ago at CERN.
Table summarizing probability of occurrence for each end-effect details estimations for 12, 7200 or undefined mission leghts compared with the initial reliability requirement set for each.
For availability related end-effects, NV mentioned that there should be also other systems included to obtain a full picture.