Dynon Skyview HDX GPS Accuracy vs TSO GPS Navigator

[RNicholson]

If someone was flying IFR with a Skyview and one Garmin/Avadyne GPS navigator and the the navigator totally failed:

Would the pilot be able to load/execute an LPV apprach with just he Skyview? Non-LPV RNAV appoach? Would the accuracy of the GPS be different ?

Hopefully thisn't isn't a dumb question.

Thanks very much

Ray

 

[Carl_Froehlich]

The short answer is no, the SkyView database does not have any approaches so there are none to load.

Two options if the TSO GPS and the VOR/LOC/GS receiver (if one is installed) fail and you cannot fly to an airport with VFR landing conditions:
- Use a paper approach chart, or Foreflight to display the approach. Follow the listed waypoints. If you have a lot of time you could enter the approach points into the SkyView as a new flight plan, but not realistic, I do know a couple of SkyView IFR pilots that do this as a backup for the airports they frequently use,
- Use the Seattle Avionics chart data. Here the approach is displayed on the SkyView screen and your position (the nice little moving airplane) is geographically correct as you fly the approach. No vertical nav information is displayed. Follow the non-precision GPS approach rules.

Note, neither options provides CDI or GS indication, or is legal. For such an emergency legal is not the prime consideration.

On the second question, the SkyView GPS accuracy is more than adequate for this non-precision apporach emergency application.

Carl

 

[GalinHdz]

Personally, after 10yrs experience with SkyView, I would not hesitate to use it to do a non precision approach in an emergency.

 

[RNicholson]

Thanks for the replies. That's a big help.

Cheers

Ray

 

[airguy]

Personally, after 10yrs experience with SkyView, I would not hesitate to use it to do a non precision approach in an emergency.

Agreed - I'm in the same boat with you - but in the actual event, if you chose to declare an emergency and follow this route, and a VFR airport existed within your fuel limitations, you might still get called on the carpet with the FAA for not pursuing the non-emergency path. Not sure how that would turn out.

I suppose "Forecasts are unpredictable and weather can change quickly, I used the known option I had at hand" might be a valid argument for the pilot.

 

[GalinHdz]

Agreed - I'm in the same boat with you - but in the actual event, if you chose to declare an emergency and follow this route, and a VFR airport existed within your fuel limitations, you might still get called on the carpet with the FAA for not pursuing the non-emergency path. Not sure how that would turn out.

I'll deal with that situation once I am safe on the ground.

 

[swatson999]

Would the accuracy of the GPS be different ?

Theoretically, the Dynon is probably better. E.g., my GNS 430W updates at 1 Hz, while the Dynon is at 4 Hz. But it also depends on the sensitivity of the antennae and how many satellites are used in the LSQ solution. In the real world, I doubt you'd notice any difference...they're both solving the same system of [dX, dY, dZ, dT] vectors to find pseudorange. The math is the same.

 

[Rhino]

Might be that new math.

 

[swatson999]

Ah, shades of Tom Lehrer...