Is this rocket science ? Am I a complete doofus ? I employ people adept at creating good customer perceptions,

Question

and then wonder why they seem to be covering up. Our safety critical computer systems don't work very well. It must be something about the calibre of the people I hand-picked.

Answer 1

Hire a company to do psychological testing.

Answer 2

if you're coming on here to vent and not really know the answer, then your staff doesn't respect your authority or feel motivated to do the job correctly.  why would they cover things up?  there could be several reasons, but they can and they are.  it's up to you to figure out these reasons and not be shy about taking care of the situation.