Are 'Single 180 Turn From Downwind to Final' and 'Stall-spin on Turnfrom Base to Final' mutually exclusive?

On 7/29/2016 8:33 AM, wrote:

Turning flight presents a more dynamic visual picture then straight flight.
Most normally equipped humans are better at assessing and reacting to the
changing energy state of the glider (relative to landing area & speed) as
well as detecting conflicting traffic and other hazards during wings level
straight flight than during turning flight. This may be due to the less
dynamic visual presentation in straight flight. This is especially true
while under stress.

Hey Matt, howzis for a data point? The 2nd-most-stressful landing approach I
ever made (microburst [just like #1 & #3] - not recommended for the
faint-hearted!) was done in the Zuni to a (shortish, with drop-off to an
arroyo at the threshold) prairie runway on which I'd never before landed (Owl
Canyon's SE one), from a close-in circling approach, with zero flaps until
v-e-r-y short final, begun from overhead the field at ~3,000' agl and
completed with (essentially) only a 270-degree turn from crosswind to final.
Gives me the mild shakes just recalling it!

Judging the "lower altitude bits" angle of bank was trivially easy compared to
deciding when to steepen the "downwind" portion of the turn into the "downwind
to final" portion. Why? The breathtaking descent rate (estimated later at
~3,000 fpm) "visually overwhelmed" the normally-to-be-expected sight picture
for "normal conditions." How bad was it? It nearly gave me heart failure, when
- for a brief, "I didn't, did I?!?" moment on downwind - the *vertical* ground
rush (contrasted with the downwind's seemingly-absent, more expected,
*horizontal* rush/related rapid progress over the ground) made it seem as if
I'd turned the wrong way onto downwind. I knew I hadn't, but it alarmed me so
much I "wasted" a few moments looking back over my left shoulder just to see
if there was still dust blowing from the SE immediately off the east end of
the target runway. (If I'd turned upwind rather than downwind, a serious
accident would likely have been in my immediate future.) The microburst
downwind sight picture and "over the ground feel" was more akin to what you'd
expect from turning downwind the wrong way on a "normally breezy day...i.e.
agonizingly slow progress over the ground in conjunction with a dismal
L/D....sort of like flying through molasses in terms of "expected downwind
progress." Despite trying to make a conservatively judged approach - e.g. not
planning a base much beyond the approach threshold, etc. - for a while it was
looking as if base would be made entirely within the shortish (2,000'?) runway
length...and crosswind had been at midfield!

As it was, I straightened up on final *maybe* 300' beyond the lip of the
dropoff (quite possibly less...no one on the ground saw the approach to share
their estimates), but I was too focused on judging final approach to give that
estimate much attention. Thermalling-flaps-only until past the threshold lip,
and still several hundred feet aloft; down and stopped well before midfield
after not using the wheel brake (trying to minimize the walking retrieve -
stress removed, we humans revert quickly to "energy saving mode," ha ha!).

I'd reckon prolly 95-98% of my attention throughout the approach was devoted
to "getting the approach path correct" with the remainder being "the usual"
airspeed/coordination cross-checks. There was very little "waiting for the
situation to develop" aspect to this approach, as is typically the case in
more routine patterns. Thanks to the sink rate, things developed "all too
quickly!" as in from 3,000'agl atop midfield. followed by two quick,
thermalling-flaps-only, 360s and on the ground. The first 360 was to clear the
pattern, positively locate a 1-36 I'd figured would opt to land before I did
(he turned out to be clueless, afterward, but got away with it just fine!),
and indubitably verify ground winds (as in "Where in heck is the center of the
downburst?), the second one was the pattern itself.

I don't remember my target pattern airspeed, but it likely wasn't all that
much higher than normal, because throughout, the air - other than being
abbie-normally descendant - was astoundingly smooth, so the primary airspeed
tasks seemed likely to be "only" retaining sufficient energy to deal with
low-level shear while not "overdoing" things. Control wasn't an issue (not the
case with #1 alluded to earlier, and to a lesser extent, #3).
- - - - - -

While it is true that many of you normally performing well trained pilots
can safely fly all kinds of approaches, common sense suggests training and
establishing flying habits that are more likely to result in safe outcomes
when normal conditions and normal performance deteriorates.

I agree with your general sentiment, but would add that "actual reality" is
the ultimate arbiter of "what must be done" in every landing pattern. Under
the above conditions, I doubt I could have pulled off "a full rectangular
pattern" that wouldn't have terrified me even more than the one performed, due
to the (almost certainly likely) need to turn final well within the runway
western/downwind boundary, and (at some point) to be facing a rapidly
decreasing headwind...my overshoot concerns weren't far behind my undershoot
concerns. As with undershooting, the overshooting options on that runway are
nonexistent, short of barbed-wire fence/railway
embankment/fence-in-borrow-trench/interstate highway/fence/etc., or, (major
yikes) trying to convert to a howling crosswind landing to the south on open
prairie. I dunno if the preceding explanation makes sense, but under the
circumstances and at the time, an "analog" circling pattern seemed more
amenable to fine-tuned approach adjustments than did a "digital" rectangular
pattern, while also likely maximizing runway ahead without wasting runway behind.

I didn't "originally plan on" a circling pattern, it simply seemed the best
and most natural of the available options...and worked superbly.
- - - - - -

The fact that we are still debating these things in 2016 makes me want to
beat my head against the canopy.

Aw, c'mon - please don't. The latest scientific evidence suggests doing so can
be harmful to canopies: plastic and cranial (and, the latter's contents)! A
baseline landing pattern standard is a great thing for many reasons...but I
see no fundamental harm in assessing why (and why not) it may not be the cat's
meow for *all* circumstances. You DO want your students to retain, and further
develop, their critical thinking skills, right?

Bob W.

Bob W wrote, "actual reality" is
the ultimate arbiter of "what must be done" in every landing pattern.

I'm not saying that everyone should always fly square approach patterns. I'm saying that in glider operations straight legs with well-banked instead of shallow continuous turns are a generally safer way to operate and train.

And that there are well established aerodynamic and human factors to support this as best practice.