Hello,

I'm working on a system that will suspend people above the ground, something like a hoist. The regulators involved insist that the system be jettisonable, but also that the possibility of accidentally dropping the personnel be extremely remote (1xE-9).

The solution being considered would use explosive bolts, requiring 2 or 3 in the same joint so that all must successfully fire in order to jettison. This gets the reliability high enough through redundancy.

Has anyone on the forum seen examples or design studies of systems like this?  To look at a few publicly-available FMEA or Fault Tree analyses would help me get into the right frame of mind for doing my own.  They wouldn't have to be exactly about exploding bolts, just evaluations of systems using redundancy to prevent catastrophic failure.

Searches are turning up the usual suspects for me, design standards and reliability handbooks - all very valuable but it would be very informative to see how it looks when the analysis is done.

Thanks, in advance, for any suggestions you can give.  

Steven Fahey, CET