[johnwalkr]

It can be opposite of your interpretation too. If you make 100,000 cars in a year, each step is done at least 100,000 times and it's justified to have a single wrench, with single non-adjustable torque value, and automated datalogging of applied value for a particular step. Or even a robotic process. Maybe even computer vision to check fastener length.

If you make 10 or 500 planes in a year, you have to rely on multiple people to use multiple torque wrenches, with multiple attachments, to follow multiple procedures to assemble multiple planes using fasteners of multiple lengths, nearby multiple other processes and people. There is a big emphasis on procedures and traceability but there are still so many potential failure points that can go undiscovered for a long time.