Look at the Dynon D10A or D100A for a
backup instrument. Cost is right and they perform very well. Flown several
approaches with this instrument for attitude and heading and found it to be
very accurate. You can increase the directional accuracy by purchasing an
optional MSU.
Pat Brunner
-----Original Message-----
From: Lancair Mailing List
[mailto:lml@lancaironline.net] On Behalf Of Douglas
Brunner
Sent: Tuesday, May 29, 2007 9:51
AM
To: lml@lancaironline.net
Subject: [LML] Tru Trak ADI vs.
Standard AI
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.