After the terrible Challenger explosion in 1986, Richard Feynman was included on an independent panel to find out what went wrong.  He discovered a profound difference between engineers’ and managements’ probability estimates for number of flights without failure.  One potential (and very important) reason that a system-ending failure can go unnoticed is the tendency of managers to believe top-down explanations. 

It’s vintage Feynman, inconoclastic, penetrating and brilliant:  

“for whatever purpose, be it for internal or
external consumption, the management of NASA exaggerates the
reliability of its product, to the point of fantasy.”

“For a successful technology, reality must take precedence over
public relations, for nature cannot be fooled.”

Just a suggestion with NASA in the news lately…though it’s clear the space shuttles are getting older.