I was planning a flight from Lanzhou to Lhasa when I noticed something strange with the chart I was using:
If you couldn’t tell already, this chart uses kilometers per hour for speed restrictions and meters for altitude restrictions. This is very unusual because I thought that feet and knots were used universally around the world. Even more confusingly, while they change their speed restrictions to km/h, they still record distance using nautical miles. At first I just attributed this to China being China, but then when I was planning a flight to Ulaanbaatar, I noticed that Mongolia does the same thing! Why are these countries different?
Funny you mention that because some airports will have an atis that show winds in Meters Per Second instead of knots. I’ve been wondering about that as well
Because of aircraft during the early years of aviation being mainly American and British, the foot became standard for altitude measurement. China, North Korea, and Russia (currently transitioning to feet), however, use meters for altitude measurement.
Worldwide, the nautical mile is the standard for measuring horizontally. Other lateral measurements are a mess. Most of the world measures runway length in meters while North America uses feet. Most of the world measures airport visibility in meters. Not North America, they measure it not in nautical miles, not meters, but statute miles!
When reporting weather, airports in China and Russia state the surface winds in meters per second. The rest of the world reports wind in knots.
To sum it up, aviation terminology is crazy. Some people do one thing and another person does a whole different thing. Pilots always have to stay on their toes, ready to convert.
For years, the ICAO has recommended that the aviation world move completely to metric units:
Meters
Kilometers
Kilometers per hour
Meters per second
Liters
Hectopascals
That’s right, no more knots or feet. The future of aviation is predicted to be 100% metric.
I believe It’s just recalculated for convenience as Chinese airspace uses meters as far as I am aware (and as @lucaviness very well wrote above), which you might notice with the numbers being somewhat odd (like 12100 feet or so).
In China, we use meter and kilometer. Also in aviation, we use them in all of the charts of the airport, but for some international airport like ZBAA,ZSPD. CAAC provide Charts use feet and nm. For the airspace, CAAC use China RVSM. And last year, CAAC announce they are trying to use feet and nm to instead of meter in some years
