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Aviation glossary

Horizontal Situation Indicator

What is horizontal situation indicator?

FAA handbook figure illustrating horizontal situation indicator

The horizontal situation indicator (HSI) is a flight instrument that combines a rotating 360° magnetic compass card (heading indicator) with navigation guidance, such as VOR or course deviation, on a single display. It shows your exact magnetic heading along with your selected course and how far you are off that course, reducing pilot workload by merging two instruments into one. Think of it as a heading indicator and course deviation indicator combined—giving you the whole "horizontal situation" at a glance.

Also known as: HSI, horizontal situation indicator

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