depression definition. A period of drastic decline in the national economy, characterized by decreasing business activity, falling prices, and unemployment. The best known of such periods is the Great Depression, which occurred in the 1930s.
A variometer â also known as a rate of climb and descent indicator (RCDI), rate-of-climb indicator, vertical speed indicator (VSI), or vertical velocity indicator (VVI) â is one of the flight instruments in an aircraft used to inform the pilot of the rate of descent or climb.
The Air Speed indicator provides the basic function of indicating to the pilot the current speed of his aircraft. The indicator is normally a 3 1/8â size dial face with a single pointer. Location of this indicator is typically in the top row of instruments on the left side of the panel.