On 8/22/2011 9:11 PM, Bill D wrote:


Eric, I would think if an airspeed indicator fails because the pitot
is plugged the pilot would know it long before deciding to try a low
pass.

Maybe, unless he flew through the virga or rain shortly before landing.
I've done that a number of times. My problem occurred at least 10
minutes after flying through the virga.

Now, flying a low pass with a known-bad ASI is really dumb. I
suspect if the pilot thought anything whatever was wrong with the
glider or himself, he wouldn't have tried the pass.

I agree.

We know the low pass happened - anything else is speculation. That
pretty much leaves pilot error as the top suspect for now.

One possibility: the water lies spread out in a horizontal tube in
normal fight, but pulling up lets it slide back to a bend, and Ta-da,
the pitot is now blocked. I think this water might be hard to discover
after the wreckage is moved and lies around for several days.


Low passes in a BG-12 are certainly possible to do safely - I used to
watch Ross and Kenny do some spectacular ones. However any well
trained pilot has to know it is a maneuver with very low safety
margins.

I remember thinking I wanted to do one. Just going for it seemed dumb
so I practiced at a safe altitude to see how much height I would
gain. With the glider I had, 300 feet was about the max which seemed
to leave no margin at all. I gave up the idea.

Now I'm curious - what glider and what initial airspeed did you use?

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what
you need to know tinyurl.com/yfs7tnz