Ground Speed Indicator

A Ground Speed Indicator (GSI) is a type of flight instrument that provides the pilot with the aircraft's ground speed. Ground speed refers to the actual speed at which the aircraft is moving relative to the ground, taking into account factors such as wind speed and direction.

The GSI is typically found in the cockpit of an aircraft and is an essential instrument for navigation and flight planning. It helps the pilot determine the aircraft's true speed over the ground, which is important for calculating fuel consumption, estimating arrival times, and maintaining desired ground track.

The GSI works by measuring the Doppler shift of radio waves reflected off the ground. By comparing the frequency shift of the reflected waves to the transmitted waves, the instrument calculates the aircraft's ground speed. The information is then displayed on the instrument's dial or digital display for the pilot to read.

In summary, the Ground Speed Indicator is a flight instrument that provides the pilot with the aircraft's ground speed, allowing for accurate navigation and flight planning. It is classified under the supply class Flight Instruments in the supply group Instruments And Laboratory Equipment.