Snowbird wrote:


As far as manifold-driven backup vacuum, my issue is: between us,
DH and I have about 1000 hrs. Our collective tally is:
AI failure (new instrument, less than 1 yr old) --- one
DG failue (overhauled instrument, age 4 yrs) --- one
vacuum pump failue (about 700 hrs best guess) --- one


I concur with your failures. In 1100 hrs, I've had
3 DG failures,
1 AI failure
1 Vacuum pump failure (and that was discovered in the runup).

...and...


IIRC part of the installation (and the later AD) is to establish a
chart of power settings for adequate operation in the plane in which
its installed. Your club plane should have this lurking around in the
paperwork, and it should give you a good understanding of when and
to what degree it's likely to be helpful.

The STC requires a placard with power settings measured in a flight test in your airplane at various RPM settings.



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