Introduction
The Horizontal Situation Indicator (HSI) is an essential instrument found in modern aircraft. It provides pilots with critical information about their position and orientation relative to the earth’s surface. In this article, we will explore the various aircraft positions to which the HSI presentation corresponds.
The Basics of HSI
The HSI combines two primary instruments: the heading indicator and the navigation display. It presents a wealth of information to pilots, including their current heading, course deviation, bearing to the selected waypoint, and more. Understanding the relationship between the HSI presentation and the aircraft’s position is crucial for safe and efficient navigation.
Heading Up Presentation
In the heading up presentation, the aircraft’s current heading is aligned with the top of the HSI. This means that the heading indicator on the HSI matches the magnetic compass reading. It allows pilots to easily interpret their heading and make accurate navigational decisions.
Track Up Presentation
In the track up presentation, the aircraft’s course over the ground (track) is aligned with the top of the HSI. This means that the heading indicator on the HSI may not match the magnetic compass reading. Instead, it shows the heading required to maintain the desired track. Track up presentation is particularly useful during cross-country flights.
HSI in Different Aircraft Positions
Normal Flight
During normal flight, the HSI presentation corresponds to the aircraft’s current position and heading. The heading up or track up presentation can be selected based on the pilot’s preference and the phase of flight.
Approach and Landing
During approach and landing, the HSI presentation is crucial for precise navigation. The heading up presentation is typically used to provide a clear understanding of the aircraft’s heading relative to the runway. It helps pilots maintain the correct course and make accurate adjustments.
Departure
During departure, the HSI presentation is vital for navigating the aircraft along the planned departure route. The track up presentation is often preferred as it allows pilots to visualize the desired track and make necessary course corrections.
Enroute Navigation
During enroute navigation, the HSI presentation helps pilots maintain the desired track, especially during long-distance flights. The track up presentation is commonly used to ensure the aircraft stays on course and to facilitate efficient navigation.
Conclusion
The HSI presentation in an aircraft corresponds to various positions and phases of flight. Whether it’s the heading up or track up presentation, pilots rely on the HSI to accurately navigate and maintain their desired course. By understanding how the HSI relates to their aircraft’s position, pilots can make informed decisions and ensure a safe and efficient flight.