Position Deviation Indicator

A Position Deviation Indicator (PDI) is a tool used in aviation to provide pilots with information about their aircraft's position relative to a desired flight path. It is commonly used in instrument flying and helps pilots maintain accurate navigation.

The PDI typically consists of a needle or pointer that indicates the aircraft's position in relation to a desired track or course. The needle moves left or right to indicate the deviation from the desired track. The PDI is usually part of an instrument panel display that also includes other navigation instruments such as an attitude indicator, heading indicator, and vertical speed indicator.

The PDI works in conjunction with a navigation system, such as a VOR (VHF Omnidirectional Range) or GPS (Global Positioning System), to provide accurate position information. The navigation system determines the aircraft's actual position, while the PDI displays any deviation from the desired track.

By monitoring the PDI, pilots can make adjustments to their heading or course to correct any deviations and stay on track. This helps ensure safe and accurate navigation, especially in low visibility or instrument flight conditions.

Overall, the Position Deviation Indicator is a valuable tool for pilots to maintain precise navigation and stay on course during their flights.