On 1/30/2014 5:09 PM, wrote:
An email correspondent asked me to explain why low-altitude thermaling is
apparently so dangerous. After all, he (and I) have never unintentionally
spun at high altitude, so why is it so bad to thermal down low? He
suggested the answer might be of more general interest so here it is.

---

It's not really "more likely to spin" but surely "more likely to get in to
big trouble."
Much good stuff snipped...

The stall-spins come from very low altitude maneuvering after the
thermaling attempt expires. If you try to thermal at 400 feet, you give up
at 300 feet... and 40 knots and pointed the wrong way. Now you have to do a
lot of last minute maneuvering to get to the field.
More snippage...

The biggest danger is that these attempts will lead to a
low, tight, slow pattern, and the last minute maneuvering can easily set up
the stall spin.

John's assessment concludes (and I agree with him) that low thermalling
attempts can easily lead Joe Pilot to enter what I call a "drunken sailor"
landing pattern. You know...staggering around erratically while J.P. figures
out what to do, when.

Be aware this tendency isn't limited only to unsuccessful attempts to thermal
away from down low. Over the years, I've seen it with some regularity at club
camps (when pilots of various skills fly from a new-to-them field) and when
winching (ditto the camp/unfamiliar field scenario, plus perhaps, patterns
entered from an unusual point (e.g. directly above the intended landing
runway, from a lower than home-field-typical height after a poor launch or
premature release or whatever...).

The drunken sailor pattern isn't limited to lower time pilots, either, in my
observation.

One of the funnier (to my dry sense of humor, anyway) instances occurred at a
winch camp (no other power or glider traffic; single paved runway;
calm/unsoarable conditions) when a multi-hundred-hour, XC-experienced, pilot
in a nose-hook-only 2-33 released above the winch at perhaps 600' agl. Under
the circumstances, it shoulda been a no-brainer to simply ease over into a
downwind via a single 180, and land short for the next snap after the 2nd
180...with maybe some practice maneuvering thrown in just because he could and
conditions (no other traffic) safely permitted. Instead, a series of
altitude-devouring, genuinely puzzling - pointless, to inquiring minds, when
the fact a downwind to the paved runway would eventually be required (no
off-field options within reach) - wanderings and meanderings ensued, to the
point I began to worry we might be about to witness a crunch. Happily, the
eventual arrival was crunch-free...but the "actual pattern" was dubiously
worrisome to me, so much so that I engaged the pilot (a soaring friend) in
post-flight conversation, the gist of which was, "What were you THINKing (and
doing)?!?" What was funny about it was his explanation matched what my mind's
eye had seen...it truly HAD BEEN a drunken sailor pattern, and he truly had
not had any plan he was attempting to execute between the release and the
(eventual) moment he realized he needed to "do something" if he was going to
land safely. It was funny only because we both could laugh about
it...lesson(s) learned for him, I figured. In any event I never again saw him
fly with his brain so obviously not fully engaged.

But being my club's newsletter editor, I was subsequently surprised to find
Joe Offending Pilot was offended (happily, only in the short term) to see that
situation described & discussed in the next month's newsletter's safety
article, even though it was done in a manner anonymizing the culprit's
identity. I think he was offended because he was still embarrassed. A year or
so later we were both laughing about it.

So...your future glider arrivals are likely to be safer if you work actively
to avoid the drunken sailor pattern, regardless of actual circumstances, low
thermalling induced or not.

Bob W.