Of the multitude of aviation related questions that popped into my mind when I commenced flying some 20 years ago, the only one left unanswered is:
Why is aviation not standardised with regard to 'weights & measures'?
Altitude in feet & metres, VMC cloud separation in feet & metres, fuel brought and used in IMP gallons, U.S. gallons, litres, pounds & kilogrammes!
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bottums up !