Dynon SkyView includes an HSI page whenever connected to a supported external navigation source. The HSI page offers a precise navigation tool to guide pilots throughout the en route, terminal and approach phases of flight. It also reduces pilot workload and offers a cost-effective and space-saving alternative to traditional mechanical HSI or CDI instruments.
The HSI data comes from external panel mounted or portable navigation devices, or SkyView's own moving map software (available for purchase in late 2010 - trial for US customers available now). These devices can either be interfaced directly to Dynon SkyView screens or through the optional ARINC-429 Converter*. When utilizing the serial ports on the SkyView screens, the system supports the Garmin SL30 NAV/COM and many GPS units that use the NMEA-0183 or aviation data formats. The optional ARINC-429 converter expands the interface to include a larger variety of NAV radios and devices, including the popular Garmin 430/530 series.
When slaved to a GPS source, the HSI displays a CDI indicating the course to the next waypoint. When slaved to a NAV radio, the HSI can display a CDI from a VOR or localizer, as well as a GS (glide slope) when tuned to an ILS.
In total, the Dynon HSI display offers a powerful navigation tool that augments a moving map system, is easily installed and easy to use. Independent of whether you intend to fly VFR or IFR, the Dynon HSI display offers an affordable approach that is hard to pass by.
What is an HSI?
The horizontal situation indicator (commonly called the HSI) is an aircraft instrument normally mounted below the artificial horizon in place of a conventional directional gyro (DG). It provides an easily understood pictorial display and is one of the most popular navigation instruments ever devised.
An HSI combines a heading indicator with a CDI display, reducing pilot workload by lessening the number of elements in the pilot’s scan. The HSI instrument may also include a glideslope needle so that an ILS instrument approach can be flown with reference only to the six basic flight instruments. Among other advantages, the HSI offers freedom from the confusion of reverse CDI needle sensing.
The HSI has several components that help you navigate. The whole instrument turns, much like a directional gyro or magnetic compass card. Heading is indicated at the twelve o’clock position on the instrument. One of the key benefits of this behavior is that the compass card carries the CDI display with it so that the HSI always shows the pilot a CDI deflection toward the selected course. This provides the pilot with a “track up” birds eye view of the aircraft relative to the selected course. Overlaid on the heading ring is a bug which is manually set by the pilot to the desired heading.
The lateral deviation needle performs the same function as the CDI in a basic CDI indicator, depicting how far you are off course. When you are on course, the lateral deviation needle is aligned with the course arrow. Since the TO/FROM indication rotates with the CDI needle as well, it becomes much easier to interpret. When the arrowhead is pointed to the head of the course arrow, the selected course is inbound. When pointed away from the course arrow, it is indicating an outbound course from the station.
Some HSIs additionally present a glide slope indicator to provide vertical navigation when shooting an ILS approach. The glide slope pointer indicates aircraft position in relation to the ILS glide slope. If the pointer is above the center position, the aircraft is below the glide slope, and vice versa. Of course, SkyView's HSI depicts glideslope when a NAV source is providing one.
The accompanying picture below presents SkyView's HSI with each of the elements described. The example below presents an external NMEA-based GPS source.
Note: This simulated illustration depicts numerous HSI elements to describe their position and purpose and does not reflect an actual or possible navigation scenario.
* ARINC-429 Converter expected availability: Q3-Q4 2010