Frolics
Chu Chu
Your points are valid, it depends on the extent of the deviation from SOP. The devil as always is in the detail. Did the company expressly prohibit titanium fittings as repair, and did the employee know why the prohibition existed? It is possible that the company may have a defence if they issued strict limits to the use of such materials. A defence would be how many repairs are made in similar circumstances using titanium. If the mechanic was one of many who used such materials then its the company who would be equally culpable, but if he alone decided to repair using the material and it never happened before, or since, then its a frolic of his own.