davparlr
Senior Master Sergeant
When was flying international in the early 70s, rules were, language was English, Altitude was in feet or Flight Level (100s of feet), air speed was knots (nautical miles per hour) or Mach, and barometric settings was in inches mean sea level (QNH). The Brits often used QFE which is the setting for zero altitude at the field, something you had to be aware of. I saw that the ICAO (International Civil Aviation Organization) flight plans allows entry in metric. I certainly hope that verbal communications are still standardized.