Radio and Radar Aids Flashcards
What is a VDF Steer?
VHF Direction Finding (slowly being phased out, being replaced by radar, only a few left)
Is intended to provide directional assistance to a pilot who may be unsure of their position. You tune in to an FSS, send out a signal via your mic, and they will then be able to give you vectors on where to go.
What are the steps to getting a VDF Steer?
- Set you HI
- Tune in to an FSS and request a VDF Steer. After the request, don’t change your HI again
- Press and hold mic for at least five seconds
How do you know if an airport has VDF Steers avialible?
CFS
What is PSR?
Primary Surveillance Radar
Sends out a inquiry signal but cannot receive a response. So will bounce off the plane and back to the controller. Will also bounce off birds and precipitation and other stuff.
Not super accurate at reporting positions and even less accurate at reporting altitudes.
PSR isn’t super accurate, so what do we also have for similar purposes that is better?
SSR (Secondary Surveillance Radar)
This one sends a inquiry signal to the AC and your Mode C transponder replies with information about your location and altitude.
SSR cannot locate weather like PSR can
What equipment is required in order for SSR to get your position?
A mode C transponder
What is RNAV?
Stands for Area Navigation.
We started out with VORs, with which we creates airways (highways) to fly from one VOR to the next. But this was a pretty zigzaging way to fly and took a lot longer than flying direct.
By adding distance measuring equipment (DME) to the VORs, they could basicaly ‘project’ an imaginary VOR or station along a more direct path from airport to airport. And you could create a path to fly anywhere within the coverage zone of the VOR/DME
The CDI for RNAV shows distance off track in __
NM
RNAV CDI needles show ____ off track in ___.
VOR and ADF CDI needles show ___ off track.
RNAV: Distance in NM
VOR and ADF: degrees off track
What are the three forms of RNAV. Or, what nav systems in place can provide RNAV?
- Multiple VOR/DME stations
- GNSS / GPS
- Inertial Nav Systems (INS) or Inertial Reference Systems (IRS)
What is the RHO-THETA system?
Also called a Track Line Computer, it basically calculates a straight line using VOR/DME stations along the route.
A diagram of how RNAVs are created from VOR/DME stations
What is the Inertial Navigation System (INS/IRS)?
A self contained navigation system. Is in fact a gyro system. Unlike GPS or VORs or anything else that requires the ground station or satelite and then also a reciever in the plane all working together to get a position. This little box in the plane does it all on its own with no outside help.
Requires a small amount of time to fix its initial position on the ground (done in a few minutes while sitting at the gate)
What one important step is crucial to using an INS/IRS system?
Giving them their inital starting point or ‘aligning them’
Following alignment, what is the rate of accuracy decay of an INS/IRS system?
1 to 2 NM per hour
But position updates can either be manually entered using ground based references or by automatic updates using VOR/DME inputs