Okay
I stand corrected I read up on the FARs Part 65 and I was wrong but I never learned that as pertaining to me so I didn't remember it, so I talked about something I don't know about and that is wrong so I apologize.
And I retract the statement I made about the metric system or any other measuring system, I just remember a case of an A 320 I think that was Canadian built and bought by an American carrier and was fueled up using the metric system and wound up running out of fuel and had to make an emergency landing on an old drag strip, if it hadn't had the emergency hydraulic systems it does ,it would have been pretty bad.
There would have been a lot more to clean up than just the pilots' seats