Horizontal Situation Indicator Flashcards
What is an HSI?
Combines a heading indictor with a VOR or Omni display
Where does the heading info come from on an HSI?
Either from a manual adjustment or through a slaved gyroscope with a flux valve that sends the heading info directly to the HI and keeps it synced (so you don’t usually have to reset it every 15 min)
Why is the HSI better than a VOR on its own?
Gets rid of the TO/FROM flag
Where are HSIs usually found?
In glass cockpits
HSI Diagram
What are the warning flags for on an HSI?
Heading Flag: Tells you if the HI has somehow unsynced from the slaved compass
Nav Warning Flag: Would go off if you lost the nav signal for the VOR you’re tuned in to
GS: Lets you know you have gone off your glide slope
Besides VOR, what kind of Nav Aids can an HSI connect to?
RNAV, GPS, ILS
What does the CDI needle represent when an HSI is tuned to an ILS?
The localizer.
What can we deduce from this image?
We are flying 2.5° to the left of the runway and are slightly below the glide slope, marked by the two yellow blocks on either side of the HI. If they were sitting right in the middle, we’d be on a perfect glide slope.
Having them indicating below like in the picture means we are coming in too high.
Correction in the picture below
How many degrees off course do the tick marks represent when tuned to an ILS?
Tick marks when using the ILS are for 0.5° instead of the regular 2°. So if there are five dots on either side, you can have a maximum full deflection of 2.5°
How many degrees are the glide slope markers on the HSI?
1 dot = 0.1° (if 5 dots per side are indicated)
