I’ve spent a lot of time thinking about Andy Anderson’s posting about his HSI failure and the way he handled it.
My first observation is that he really handled it well, and dealt with a potentially big problem skillfully.
As a soon to be owner of an SR20 (April 23rd!!) I kept re-hashing what happened, and kept wondering why Andy didn’t just utilize the wing leveler like I have on the S-Tec 30 in my Piper Warrior. I routinely think about that solution for a multitude of problems. A separate solution to a bad DG (HSI) in my Warrior would be to couple the autopilot directly to the GPS. Either solution would give a reliable means to buy some time, safely.
Of course, upon further investigation of my soon to be owned C-Configuration SR20, I realized that neither option is available. The GPS can’t run the autopilot directly (I don’t think) and there’s no wing leveler function on the S-Tec 55.
This begs a few questions. First, are my assumptions correct; is there a way to run the autopilot off the GPS and bypass the HSI?
Does unslaving the HSI guarantee that the card will stay stable? (This is necessary to use the dormant HSI as a poor-man’s wing leveler.) I always thought that with a gyro failure, the card could spin erratically.
It seems that lots of things are riding upon the HSI, which seems to have some questions about reliability. Also, if one were to loose all the electric in IMC, all we’re left with is the attitude indicator and wet compass?
Any thoughts on these questions? Appreciate any input!