> Each engine was custom tailored with small modifications here and there This was true of lots of things outside NASA. This was one of the problems that kille

> Each engine was custom tailored with small modifications here and there This was true of lots of things outside NASA. This was one of the problems that killed the UK attempt to modernise the Nimrod maritime patrol aircraft [0]. They wanted to fit new wings to the old planes, but only discovered after the contract had been signed that the different airframes had not been built identically, but were different interpretations of a common plan. Each of the nine planes was in effect a completely new refit challenge. [0] https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4 https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4