Originally Posted by
dctyke
Zulu 10: If flexibility really is the key to air power, then you have to understand that it works both ways. ‘He who never made a mistake never made anything’ as the saying goes, the corollary of which is that if you want something made, then as a consequence it must be accepted that sometimes mistakes will occur.
Is it a 'mistake' to not use a shouldered bolt (fitted up to and including Mk9 and Mk 12 seats) that cannot be over tightened and use one that can. If a mod does indeed come out that has a shouldered bolt I would be asking why not in the 1st place.
I’m struggling to understand what you’re asking. Are you suggesting that the design which did not utilise a suitable shoulder bolt was a consequence of:
1. Pure (innocent) incompetence on the part of the designer, coupled with a lack of oversight by more experienced staff, or;
2. A review which noticed the potential for failure, but quietly and cognisantly ignored that matter, or;
3. A desire to save a few pennies in production by using cheaper part, or;
4. A belief by the equipment designer that an appropriate torque figure would be quoted in the accompanying servicing Tech Order, and a suitable torque wrench would be supplied to those requiring to adjust said fastener?
I do not know and cannot second guess it. Neither, I respectfully suggest, can you.
Are they all mistakes? Possibly. Are they all "honest mistakes"? No.
But to use the defence in depth principle, a good review process should have captured the first three and would have noticed the potential for number 4 to result in problems (i.e. Tech Pubs ignored, torque wrench out of cal etc) and therefore added a second defence mechanism i.e. a shoulder bolt.
You also seem to be suggesting that every design should be right first time. You’re a creationist I assume?