What is the method for converting CAS to TAS under standard conditions?

The method for converting Calibrated Airspeed (CAS) to True Airspeed (TAS) under standard atmospheric conditions involves adjusting for the increase in air density with altitude. As altitude increases, air density decreases, which means that the same calibrated airspeed will equate to a higher true airspeed.

When flying at higher altitudes, True Airspeed is generally greater than Calibrated Airspeed because of the thinner air. The conversion factor commonly used is to add approximately 2% of the CAS for every 1000 feet of altitude gain. This accounts for the reduction in air density and adjusts the speed accordingly, providing a better approximation of the aircraft's performance and fuel efficiency at altitude.

This understanding of atmospheric conditions and how they affect flight performance is crucial. It allows pilots to make more accurate calculations for navigation and fuel consumption, especially at higher altitudes where the effects are more pronounced.

Other methods, such as subtracting a percentage or multiplying by a constant factor, do not accurately represent the relationship between CAS and TAS under standard conditions and could lead to miscalculations regarding flight performance.