On Wednesday, May 15, 2013 6:01:39 PM UTC-4, Greg Delp wrote:

The pitot system did indeed have two leaks. The first and
largest is inside the Cambridge MKIV Vario itself.
The second smaller leak is inside the MKIV Speed Director.

IIRC the ASI is implemented with a calibrated leak and
flow sensor in that gear; the leak is normal...

Hope that helps,
Best Regards, Dave