Stay on Course: Understanding the Dots on the HSI

What do the dots on the HSI represent for ILS and VOR navigation?

Final answer: A dot on the Horizontal Situation Indicator (HSI) represents a deviation of 2.5 degrees for an Instrument Landing System (ILS) and about 5 to 10 degrees for VHF Omnidirectional Range (VOR) navigation.

Understanding the Dots on the HSI

The dots on a Horizontal Situation Indicator (HSI) provide essential information to pilots regarding their position in relation to specific navigational paths, such as those provided by an Instrument Landing System (ILS) or VHF Omnidirectional Range (VOR) navigation.

For ILS navigation, a single dot on the HSI corresponds to a deviation of approximately 2.5 degrees to the left or right of the intended course. This allows pilots to make necessary corrections to stay aligned with the ILS approach path and ensure a safe landing.

When using VOR navigation, each dot on the HSI represents a deviation of about 5 to 10 degrees from the selected radial. The exact deviation can vary depending on the specific VOR equipment being used. Pilots rely on these deviations to adjust their course and remain on track towards their desired radial.

By understanding and interpreting the dots on the HSI accurately, pilots can navigate effectively and maintain precision in their flight paths. It's essential for safe and efficient flight operations in both ILS and VOR approaches.