Douglas,

A standard AI is what I choose as my back-up to my 2 screen Chelton system.  I used the TSO'ed Mid-Continent 4300 series and am very happy with it. 

My thinking was this, flying with EFIS's will be significantly different than what I am used to and what I have been trained to fly.  EFIS failures are a rather common occurence, I don't know of anyone who has flown for any significant amount of time in their EFIS experimental who hasn't had a failure of some type.  (reboots, lockups, sensor errors, etc.)  Therefore, my backup is not only significantly different than primary, but it is also what I am comfortable using. 

Chelton recommends pilots new to EFIS to get 40 hours of hood work before launching into IFR weather.  Do you want backup instruments that also require new pilot training? 

Micah Froese
Lancair Legacy
150 hours



Douglas Brunner wrote:

My panel is a dual Chelton panel with 3 backup instruments; altimeter, air speed and Tru Trak ADI. I specified a Tru Trak ADI rather than a standard Attitude Indicator because of price and the fact that the Tru Trak could also show heading.  In case of a failure of my dual Cheltons (hopefully very unlikely) I would still have; altitude, air speed, heading and attitude. 

 

However, I have been re-thinking my choice of the Tru Trak ADI for the following reason.  The ADI does not display pitch, but instead displays "gyro enhanced vertical speed".  In most situations the "gyro enhanced vertical speed" should parallel pitch.  However in a situation close to stall speed, I could be nose up but descending.  In this case the ADI (if glanced at quickly) could lead me to believe that I was nose down and should pull back on the stick.  A standard Attitude Indicator would show me nose up and give me a better idea of the true situation. 

 

I spoke to the Tru Trak representative at Sun n Fun and he stated that there are stall warnings built in to the system and that I could "retrain" myself to interpret the ADI properly.  Nevertheless, I am concerned that in a difficult situation, I would interpret the Tru Trak in the way I would a standard AI.  Your thoughts and advice?

 

A drawback to going with the standard AI is the loss of the heading information that the Tru Trak can provide.  Of course, I would still have my wet compass.

 

D. Brunner

Legacy N241DB

hoping to fly in June