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!
I hope a current SR driver will clarify, but my understanding is that the S-TEC uses the gyro in the turn coordinator, not the DG. So if there were another source of heading info, the failed DG might be cut out of the loop. That other source could be GPSS, which lets the GPS drive the autopilot directly. My SR20C contract specifies GPSS. Early C’s didn’t get this, but I’ve seen posts on this site from people who have added this in the field. There are articles about this on the http://www.s-tec.com/gpss.html STEC site (showing a DG with a read NO circle over it), and I noticed a more detailed one the other day at the http://www.avionicswest.com/articles/GPSS.htmAvionics West site.
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!
We have a similar story to tell. N747TG, a SR20 C-modell, lost the electrical HSI Gyro 5 hrs after delivery, still in the DLH area (and we got it replaced immediately). What happened was:
The Gyro coasted down, and during this process the autopilot banked into a turn to the left and started flying 360s. Because we were VFR at that time, we just waited what would happen - after 720 degrees we switched the a/p off. Later we were able to fly with the a/p in the HDG mode, but because the HSI was broken, an arbitrary heading had to be used. NO FUN in real stuff. However, never did the a/p bank more than standard rate turns.
Timm Preusser N747TG
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!
It sure does sound like the 430 w/ GPSS will drive the stec 55 directly. After reading that review it is hard to imagine not installing GPSS. Thanks for the link.
I hope a current SR driver will clarify, but my understanding is that the S-TEC uses the gyro in the turn coordinator, not the DG. So if there were another source of heading info, the failed DG might be cut out of the loop. That other source could be GPSS, which lets the GPS drive the autopilot directly. My SR20C contract specifies GPSS. Early C’s didn’t get this, but I’ve seen posts on this site from people who have added this in the field. There are articles about this on the http://www.s-tec.com/gpss.html STEC site (showing a DG with a read NO circle over it), and I noticed a more detailed one the other day at the http://www.avionicswest.com/articles/GPSS.htmAvionics West site.
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!
My understanding is that GPSS is now standard and is equipped in all new aircraft. That doesn’t mean it’s free.
I hope a current SR driver will clarify, but my understanding is that the S-TEC uses the gyro in the turn coordinator, not the DG. So if there were another source of heading info, the failed DG might be cut out of the loop. That other source could be GPSS, which lets the GPS drive the autopilot directly. My SR20C contract specifies GPSS. Early C’s didn’t get this, but I’ve seen posts on this site from people who have added this in the field. There are articles about this on the http://www.s-tec.com/gpss.html STEC site (showing a DG with a read NO circle over it), and I noticed a more detailed one the other day at the http://www.avionicswest.com/articles/GPSS.htmAvionics West site.
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!