I couldn´t help not to add this pass in the debate. I took it from BEA serious incident report of Falcon 7X HB-JFN in May 2011 (runaway THS on descent to Kuala Lumpur)
A single cold solder in THS control computer nearly sent them to death-avoided by copilot, former military pilot, that recognised problem, reacted correctly, yelled at his captain who instinctivelly tried to intervene, but made only things worse and eventually saved the plane.
How such deadly dormant failure was allowed to happen? Think about this:
1.18.1.5 Human factors affecting safety analysis
An enormous amount of effort has been put into studying the human factors issues
for crews, air traffic controllers and aircraft maintenance personnel. However the
ATSB report found very little research that has examined the human factors issues
affecting design engineers and safety analysts or the factors likely to lead to errors
in design.
The ability to detect errors in design or judge whether a fault tree is complete can
be affected by a range of different factors, such as experience, available knowledge,
task complexity and the fact that omissions are relatively difficult to detect. The final
result can also be affected by time-related pressure from the organisation’s activity
and industrial programme deadlines.
hoistop