At a pressure altitude of 7,000 ft and a true air temperature of +15 °C, what is the approximate density altitude?

To determine the density altitude, we need to understand how pressure altitude and temperature affect air density. Density altitude is essentially the height above sea level where the air pressure is the same as the current atmospheric pressure at a given temperature.

At a pressure altitude of 7,000 feet, the standard atmospheric temperature at that altitude is typically around +5 °C. However, in this case, the true air temperature is +15 °C, which is warmer than standard. As temperature increases, air becomes less dense because warm air expands. Therefore, if the air temperature is above the standard value, the density altitude will be greater than the pressure altitude.

To calculate the density altitude, you start with the pressure altitude and then adjust for the temperature deviation from the standard. One common rule of thumb is that for each degree Celsius the temperature is above standard, the density altitude increases by approximately 1,000 feet. Since the temperature is 10 degrees warmer than standard at 7,000 feet, this can increase the density altitude by about 10,000 feet relative to the original pressure altitude.

By adding this adjustment to the pressure altitude of 7,000 feet, you arrive at an approximate density altitude of around 8,500 feet.