Oberon 1, I couldn't let this pass; you mentioned:
It all started with a techy down at MPA fitting a spinner incorrectly. Having done the job himself, he persuaded a junior to undersign him (wrong, I know, but I don’t know the pressures they were under at the time – unwilling to speculate).
I'm sorry, but I've been maintaining military aircraft for approx 24 yrs, and whatever the pressure, there is NEVER any excuse to get a job 'Undersigned'. That is why we are allowed to self-supervise. By getting a job 'undersigned' you are clearly putting the Ac and crew at risk.
I'm not being flippant or naive, but the rules are there for good reason, IF there was a culture of this at Lyneham:
At the subsequent inquiry, less importance seemed to be placed on the fact that he had done the job incorrectly, what everyone latched onto was his statement that “the process of undersigning is common at Lyneham, it’s always been done like that”.
then your later use of the words:
they are professional technicians who only want, at the end of the day, to do a good job
sounds a bit suspect to me.
SC