Originally Posted by F1R
If there had of been a low overcast or fog layer in this case , say at 50ft, and you have both large primary displays showing and telling you to pull up how would you catch on quick enough to trust or even look at the small back up?
I think this is a great question that should be asked by more pilots who launch off into the flag. My guess is that the question exists, but isn't verbalized.
I have SV and love it. However, what you're asking is interesting and speaks to actually using SV.
First off, there is the certified aspect of needing an independent backup within the pilot's view (this is has a defined angle and lateral separation requirement in the reg's). If the primary display failed and you had a properly installed backup, it should be fine - assuming you're trained and proficient with your instruments.
Second is the requirement for backup in an experimental airplane, as in - there isn't one.
Now, for the common sense approach. I never take off of an airport that I can't land at. A 50 foot ceiling is well below any legal instrument approaches for standard GA aircraft, which 200' AGL is lowest precision approach minimum I know of, and you'd certainly have very little time to react to any changes, let alone failures.
My direct response to your question is that, no, I doubt you'd have much time to react to anything with a 50' foot ceiling. Considering a 500 fpm descent rate for landing, that's only 6 seconds from the time breaking out to impact; not much time for any reaction - let alone instrument failure determination.
Now, a question I have is "do you trust SV for landing in non-visual conditions?". It's not legal to use SV in lieu of having the runway environment visually, but if you have an emergency - you can use any means necessary, which would include SV, to safety land. For the record, I've used a safety pilot and landed under the hood on SV - right down the centerline.