Variometer

The main purpose of a variometer is in helping a pilot find and stay in the core of a thermal to maximise height gain and, conversely, to indicate when a pilot is in sinking air and needs to find rising air. Humans can sense the acceleration when they first hit a thermal, but cannot detect the difference between constant rising air and constant sinking air. Modern variometers are capable of detecting rates of climb or sink of 1 cm per second. A variometer indicates climb rate or sink rate with short audio signals beeps, which increase in pitch and tempo during ascent, and a droning sound, which gets deeper as the rate of descent increases and or a visual display. It also shows altitude either above takeoff, above sea level, or at higher altitudes flight level.