What happens to the VOR CDI needle as it flies over the VOR station?
To fly a specific VOR radial inbound to a VOR station, use the OBS to place the radial you want to fly inbound on the reciprocal course index on the bottom of the VOR indicator. You should have a To indication, and the CDI needle will deflect in the direction you need to turn to get to the station.
What is CDI in VOR?
A course deviation indicator (CDI) is an avionics instrument used in aircraft navigation to determine an aircraft’s lateral position in relation to a course to or from a radio navigation beacon.
What is the difference between a CDI and HSI?
A standalone CDI (Course Deviation Indicator) is an instrument that shows your deviation from a VOR radial that is selected using the OBS (Omnibearing Selector) knob located on the instrument itself. An HSI (Horizontal Situation Indicator) is an entirely separate instrument that combines a CDI and a heading indicator.
How do you read a CDI VOR?
On the CDI instrument just read the number displayed on the compass card (±90° of the radial). In the left figure above, the shortest path to join the VOR radial is 340° (=070°-090°) (blue straight arrow). The VOR is located in the sector between 340° and 070° as we are in the TO region.
What does the VOR and ILS CDI mean?
The VOR and ILS CDI indicates difference, in degrees, between the radial selected and the radial sensed. If the plane was far from the VOR and we turn the course pointer 5 degrees, the CDI will move to one side.
How does DME work when flying to VOR?
VOR does nothing with DME. DME is completely independent piece of equipment that was introduced later than VOR. The only relation is that there is a standard correspondence between VOR and DME channels and the DME receiver automatically tunes to the DME frequency corresponding to the VOR or ILS frequency tuned on your VOR/ILS receiver.
How does the HSI work on a CDI?
The old CDI would just have a radial set in the OBS and show your deviation (which could have reverse sensing depending on which radial you tuned) in relation to that radial. The HSI serves as a heading indicator as well as a CDI and be coupled to a VOR or a GPS.
How does the OBS work on a CDI?
You’ll notice it has an OBS (omnibearing selector) knob in the bottom left that will change the outer ring of the CDI which will determine what VOR radial to analyze your position against. The standalone CDI will not display any information about your current heading, only the VOR radial you have tuned with the OBS.