What is the approximate calculation for the rate of climb?

The rate of climb can be approximated by understanding the relationship between true airspeed (TAS) and the still air gradient, which is the rate of climb in still air conditions. When you multiply the still air gradient by the TAS, you effectively determine how much altitude is gained for a given distance traveled horizontally in still air. This means that the rate of climb is fundamentally linked to the aircraft’s speed and the gradient of the climb.

When in level flight, the still air gradient represents a specific angle of ascent, often given in feet per nautical mile. By multiplying this gradient by TAS, you can derive the vertical speed, thereby giving you the rate of climb. This approach encompasses the effective use of performance data considering both the aircraft's speed and environmental influences, allowing pilots to accurately determine how efficiently they are gaining altitude.

Other options do not accurately reflect the calculation method for rate of climb. Simply dividing TAS by the still air gradient does not provide a meaningful measure of climb performance. Factors like combined pressure and temperature can influence aircraft performance but are not used directly in calculating the rate of climb. Similarly, suggesting that the rate of climb is constant across all altitudes disregards how performance variables change with altitude due to thinner air and varying atmospheric conditions.