Bearing Deviation Indicator

A Bearing Deviation Indicator (BDI) is a navigational instrument used in aviation to display the deviation between the aircraft's current heading and the desired course or bearing. It provides pilots with a visual indication of how far off course they are, allowing them to make necessary corrections to maintain their intended track.

The BDI typically consists of a compass card or dial that represents the aircraft's heading, and a needle or pointer that indicates the deviation from the desired course. The deviation is measured in degrees, with the needle pointing to the left or right depending on the direction of deviation.

BDIs are commonly used in conjunction with other navigation instruments, such as a Horizontal Situation Indicator (HSI) or a Course Deviation Indicator (CDI), to provide pilots with a comprehensive picture of their position and track. By monitoring the BDI, pilots can make adjustments to their heading or course to stay on track and reach their intended destination.

Overall, the Bearing Deviation Indicator is a valuable tool for pilots to maintain accurate navigation and ensure safe and efficient flight operations.