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Path: utzoo!watmath!clyde!burl!ulysses!bellcore!decvax!decwrl!glacier!singh
From: singh@glacier.ARPA (Harinder Singh)
Newsgroups: net.aviation
Subject: Re: biography and story
Message-ID: <3427@glacier.ARPA>
Date: Thu, 23-Jan-86 11:50:42 EST
Article-I.D.: glacier.3427
Posted: Thu Jan 23 11:50:42 1986
Date-Received: Sat, 25-Jan-86 03:53:43 EST
References: <862@unc.unc.UUCP>
Reply-To: singh@glacier.UUCP (Harinder Singh)
Organization: Stanford University, IC Laboratory
Lines: 34
Summary: Another scare from the ground

..........
Mr. Lipscomb's experience with the sound of a large airplane running up
on the ground while he was flying above in a glider reminds me of a 
similar experience:

	I was giving a friend a ride in my favorite glider to-date (no, make
that a sailplane), a Grob Acro, out of Sky Sailing Airport in Fremont, CA.
We had a high aero-tow to five or six thousand feet just outside the TCA and 
just sort of lazed around to get a long ride.
	As we came down to about 2000 feet and I started positioning myself
for imminent pattern entry, we heard a scary thud or buffet coming from the
tail-section. Like nothing I had ever experienced before. I looked back, 
around, and everywhere but could see nothing. Meanwhile, the dull thuds 
occurred again, somewhat irregularly. I could have sworn from the feel of it
that they were coming from the tail section.
	The glider was handling just fine, but I feared imminent structural
failure. Especially since the aircraft IS an aerobatic sailplane that is
flown by many different people, some of whom may push it's limits. You may
think it difficult that someone would take it beyond +6G, but I had had a 
definite admission from someone of something close ( highly illegal in the SF
Bay Area airspace).
	As you can gather from the context of this posting, the "problem"
was on the ground. On the 45 to the pattern entry we saw plumes of smoke 
rising from the upwind side of the runway. Been a tow-plane accident, I
thought. But the runway was clear so our cautious landing was un-eventful -
not that a glider pilot has many choices once he has lost altitude.
	Turned out that everything was OK! No accident or anything - the 
airport is RIGHT NEXT TO a drag-strip where some jet-cars (?) were
starting up. That is where the booms and the smoke had been coming from....

	And now for a question: what can one do during a pre-flight of an
aerobatic rental aircraft to ensure that it has NOT recently been over-
stressed by someone?? Anything other than the usual precautions (which
may NOT reveal latent problems)?