Refer to figure.
EASA learning objective 022.02.05.01.01 states: List the two units used for VSIs and state the relationship between them: metres per second; feet per minute.

Countries such as China, North Korea and Russia have traditionally used metres instead of feet for altitude measurement so rates of climb and descent are expressed in metres per second (m/s) rather than feet per minute (ft/min). You are required to be able to convert feet per minute into metres per second and vice versa.

One metre is 3.28 ft and there are 60 seconds in a minute so to covert ft/min into m/s divide by 3.28 then divide by 60.

• 650/3.28 = 198.17
• 198.17/60 = 3.3 m/s

The above method requires the use of a calculator, fortunately there's a much simpler method, to obtain an approximate answer, which requires only simple mental arithmetic! Indications in feet per minute are approximately 200 (3.28 x 60) times larger than the equivalent metres per second indication.

To convert ft/min to m/s divide by 200 and to convert m/s to ft/min multiply by 200.

• 650/200 = 3.25 m/s