By the seat of their pants
Canada went fully metric in the late 1970s after a phase-in process that started in 1971. But it still had its fair share of hiccups over confusion about metric versus imperial units, including a 1983 Air Canada flight running out of fuel. Air Canada had been measuring fuel in pounds for years before finally switching to kilograms.
The Boeing 767 jet, Canada's first aircraft using metric measurements, had been filled with too little fuel on that particular day. The flight, scheduled to travel from Ottawa to Edmonton, had to make an emergency landing in