Cambridge L-Nav audio vario just ate it...

On Nov 13, 3:26*pm, Papa3 wrote:
On Nov 13, 5:50*pm, Bruno wrote:

On my last flight my audio vario suddenly started to read a consistent
300-400 fpm too high for the present conditions. *I have a mechanical
vario that remained accurate and on my L-Nav screen my average fpm
sink rate was correct. *Any ideas what I can check? *It was really
annoying when I was sinking at a true 300 fpm on glides but my audio
was telling me I was going up 100fpm. *If only it was always that way
in real life! *

Thanks,
Bruno - B4

Hi Bruno,

What you wrote is a little confusing. *I wonder if you meant that the
dial was showing high along with the audio tone, while the LNAV LCD
screen showed a believable average (and netto)? * *As you probably
know, it is possible to adjust the zero and gain on the vario through
the configure screen, and the manual tells you what the acceptable
zero number ranges are. * *It would at least be interesting to have a
look at those values and see what they show. * But, it wouldn't
explain (at least to me) while the dial and audio are out of sync with
the other values.

Sounds like a trip to NK is in order.

P3

That's interesting. I have an old Cambridge CAV series audio vario in
my Speed Astir. Every once in a great while, it will start to read
200-300 fpm climb when I'm NOT climbing. This usually happens several
hours into the flight, when I'm fairly tired of the annoying noises it
makes too much of the time anyhow. In its defense, it is probably just
trying to make up for the seemingly endless fields of sink that force
it to honestly inform me that I'm dropping like a frigging rock (and
have been for the last dozen miles). Perhaps it's just trying to cheer
me up?? I used to think maybe it was voltage related, when I was using
a 12v battery, but it does it even with my 14v setup.