Derek Copeland wrote:
snip
T.E. probes produce a small amount of negative pressure
which increases with airspeed

Actually an ideal TE probe creates a "negative" differential pressure
exactly equal to the positive differential pressure of the pitot tube
(relative to static). If the ASI was connected to Pitot and TE (instead
of static) then the ASI would read 70% high, because dynamic pressure
is related to airspeed squarred.

An ASI works by comparing pitot pressure with static
pressure, so reducing the static pressure will as you
say increase the ASI reading. However the glider had
been flown in this configuration for some time, so
the pilot would have been used to any errors produced.

No way he compensated for a 70% high reading.

The AAIB actually set up a rig with the same configuration
and found that the errors where quite small. Presumably
the high pressure generated by the pitot was much greater
than the low pressure generated by the TE probe.

This is not correct. Either the explanation is wrong or there was a
problem with the test.

At 11:06 17 October 2006, Doug Haluza wrote:

Derek Copeland wrote:
The UK Air Accident Investigation Branch (AAIB) has
recently published a report on a fatal accident involving
a DG600 sailplane back in 2005.

The only anomaly found was that the ASI static was
connected to the Total Energy probe, which might have
caused the ASI to misread. However tests showed that
this would only cause minor errors.

This seems completely wrong to me. The TE probe should
produce a
pressure below static equal to the dynamic pressure,
so the
differential pressure to the ASI would be doubled,
and the ASI would
read high by 70%. I would not consider this a minor
error!

I would seriously question the test results, and the
report's
conclusions based on this.