Virtuaalkõrgusega

Virtuaalkõrgusega, a term derived from Estonian, translates to virtual altitude. It is a concept used primarily in aviation to describe the altitude an aircraft would be at if the air density were standard at the pressure altitude. Standard atmospheric conditions assume a sea-level pressure of 1013.25 hectopascals (hPa) and a temperature of 15 degrees Celsius. As air temperature deviates from the standard, the actual indicated altitude can differ significantly from the true altitude.

When flying in cold air, the air is denser than standard. This means that a given pressure altitude will correspond to a lower true altitude than it would under standard conditions. Conversely, in hot air, the air is less dense, and the true altitude will be higher than the pressure altitude would suggest under standard conditions. Virtual altitude corrects for this temperature deviation, providing a more accurate representation of the aircraft's height above sea level, particularly in environments where extreme temperatures are common, such as high altitudes or polar regions. It is a crucial calculation for pilots to maintain safe separation from terrain and other aircraft, especially during takeoff and landing operations in non-standard temperature conditions.