Nelson Funston

danlj wrote:

I write this not to analyze Mr. Funston's accident, but because the
concepts of "uncommanded roll" and "new obstacle" inspire me to remind
fellow soaring pilots that windy conditions are always accompanied by
significant turbulence close to the ground, exacerbated by nearby
obstacles. This turbulence is invisible, and can indeed roll our
aircraft enough to cause a tip strike or loss of control.

While this does not invalidate what Dan says, pilots may be interested
to know the "obstacle" was basically flags marking changes in the
runway, and would not affect the wind on the runway. They did add some
distraction for the pilot, however, as it was his first launch since the
new runway was marked on a portion of the ramp. Previously, the entire
width of the ramp was "available". My guess is the distraction was a
much bigger factor than the wind.

--
Eric Greenwell - Washington State, USA
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A: Causes of aircraft flight accidents fall into just 3 categories:
1: Something about the a/c "broke" (in the broadest sense,
including linkages not sufficiently connected)
2: Something about the pilot "broke" (again, in the broadest sense,
including natural failures of perception, which we call 'illusion.')
3: Something about the air was "broken" (again, broadly, especially
including vortices = turbulence).


I stick with my use of the term "uncontrolled" and since it appears
that neither the pilot nor the air were broken I choose 1) above as
most likely.

Mike

On May 13, 12:44*pm, Bob Whelan
wrote:
DESCRIPTION
* AIRCRAFT ON TAKEOFF ROLL, WING STRUCK THE PAVEMENT AND THE AIRCRAFT
CARTWHEELED, EPHRATA, WA

In somewhat of a contradiction to the FAA report, newspaper and
eyewitness accounts state that
snipped

I think that "uncommanded" roll might be more precise than
"uncontrolled", for technical reasons.

Good, thoughtful stuff snipped...

Where this thread has gone is - to me - an excellent example of how
*thoughtful* speculation (perhaps it is better described as
"imagination") may wisely be used to enhance one's own safety when
soaring. *No need to wait for the (too often, hopelessly homogenized)
NTSB reports...

Respectfully,
Bob - no fan of off-the-wall speculation -W.-


What a nice thread in response to a sad situation.
Sorry Nelson was hurt, hope he recovers well.

I am very glad to see the shift from "let's not talk 'til a report is
written"
toward a "let's consider possibilities and see how I could avoid
similar scenarios." That is the most productive view to take
following
any breakage, human, airframe or atmospherically.

That was also the total gist of my presentation at the ABQ Convention,
titled "What the NTSB will Never Say About 2007 Fatalities."

Keep after this concept folks. It helps build mental flexibility
which I believe is vastly undertrained in glider cockpits.

Cindy B

Another fan of constructive speculation for personal-use accident-
analysis
www.caracolesoaring.com

Another fan of constructive speculation for personal-use accident-
analysis

Hey Cindy,

If you're a fan of constructive speculation, here's a good one for you
to chew on; I'd welcome your observations.

On Sunday 5/11, a routine pattern at Turf turned into a nightmare on
final approach when I ran into 20+ knot sink. This was one or two
heartbeats after I had deployed spoilers upon judging my altitude to
still be a bit too high. I pulled the brakes back in as soon as I felt
the glider going into freefall, but the sink persisted and I soon
found myself wondering if I could clear the power lines.

Of course, faced with a very serious question of whether I could clear
power lines, I assumed I could not. I turned hard left choosing to
deal with mesquite bushes instead, and hit the ground hard before I
could complete the turn. (That told me that the score would have been
power lines One, tuno Zero.)

As I look back at the incident, which mangled a brand new ASG 29, I
ask myself, as anyone would, what I could have or should have done
different. (Begin Monday morning quarterbacking.) I really can't
identify much. The pattern was textbook, the altitude and IAS good. I
would normally have chosen a little more IAS in the pattern but I was
conscious of a pair of 2-33's landing in front of me so I stuck with
60 knots indicated. Winds were about 10 knots steady right down the
runway.

Very thankful, all the same, to be walking, talking and departing for
Moriarty in high spirits tomorrow morning.

~ted/n2O

On May 15, 10:13*pm, Tuno wrote:
Another fan of constructive speculation for personal-use accident-
analysis

Hey Cindy,


If you're a fan of constructive speculation, here's a good one for you
to chew on; I'd welcome your observations.

On Sunday 5/11, a routine pattern at Turf turned into a nightmare on
final approach when I ran into 20+ knot sink
snip
As I look back at the incident, which mangled a brand new ASG 29, I
ask myself, as anyone would, what I could have or should have done different.

As I look back at the incident, which mangled a brand new ASG 29, I
ask myself, as anyone would, what I could have or should have done
different.

I was giving a field check to a new (rated) club member and after we
turned final i remarked "nice, perfect height, perfect distance". Five
seconds later I couldn't see the rwy because of the tree tops above us.
The only thing that saved our bacon was that we had enough speed to make
the rwy.

Reminds me of a story of where a Shorts pilot hit a micro burst on
approach and fire walled the throttles - mandating a very expensive
teardown and inspection of the engines. At the "inquest", he was asked
"why did you push the engines to 120% of their rated power"? The
response was "because I couldn't push them higher".

Tony V.

On May 16, 2:54 am, CindyASK wrote:
So, what happened to you? Gradient, mondo sinkhole,
virga shaft? I don’t know. I would bet a quarter that you fly a
wider, longer, shallower pattern than I would. I would hope that you set
up closer, tighter, higher, dirtier patterns when you get the lovely
Schleicher back from the New Mexico team.

I agree with Cindy, though in my ASH-26E and previously in my ASW-20B,
I would apply landing flaps on base leg, having flown downwind with
thermalling flaps. I apply spoilers while turning final and typically
have 2/3 to full spoilers until touchdown. If the wind is less than
expected, I'll often slip to make up for being a bit too high.

I (almost) ALWAYS stop within less than a fuselage length of where I
had planned, and typically place the wingtip in my wife's waiting
hand.

In an ASK-21, I'll do something similar - 1/3 spoiler on base and 2/3
on final.

At the end of the day, the planned stopping point is mid field on our
3700' runway, so I typically turn base abeam the numbers.

I've encountered a few downbursts here in Colorado, and pretty much
always in the pattern. Prior to base leg, I hope I have time to turn
toward the runway as I push everything forward. On base/final, since
the flaps and spoilers are mostly out, my nose is already pointed down
to maintain airspeed. If the bottom falls out from under me, I slam
the spoilers shut, push the flaps to 0 and at the same time am pushing
the stick forward.

So far, I've always flown out the side before reaching the ground, but
there have been times when I was in what seemed like 45-60 degrees
nose down, near weightless and airspeed dropping. So if that had
continued for 5 more seconds, I would have been hitting the ground
while still in this recovery. Accident statistics indicate that it's
better to hit a bit fast but flying and wings level, than stalled...

The recovery from one of these adventures typically ends up with a
normal, full flap and some spoiler landing maybe 500-1000' farther
down the runway. Once I fly out the side of the sink, I have excess
airspeed which I convert back to enough altitude to allow me to again
extend flaps and spoilers before the roundout and flare to landing.

-Tom

Cindy: Thank you, good stuff. I don't have time to answer all your
questions but the day was clear, blue and quite good soaring -- my
last two thermals were 8 and 10 knots. Observed winds while I was in
the pattern were on the lite side (very little drift in the base leg).
It wasn't a loose pattern, like you I like to keep mine rather tight.
Turf has 3 parallel runways but while I was on base I couldn't tell if
2-33 #2 was taking center or right.

Off to Moriarty

~ted/n2O

On May 16, 7:04*am, Tuno wrote:
Cindy: Thank you, good stuff. I don't have time to answer all your
questions but the day was clear, blue and quite good soaring -- my
last two thermals were 8 and 10 knots. Observed winds while I was in
the pattern were on the lite side (very little drift in the base leg).
It wasn't a loose pattern, like you I like to keep mine rather tight.
Turf has 3 parallel runways but while I was on base I couldn't tell if
2-33 #2 was taking center or right.

Off to Moriarty

~ted/n2O

Bummer Ted - I hope 2NO is quickly and easily fixed. Sounds like the
day, while strong, didn't have any of the classic indicators for
extreme sink.

I've been thinking lately about how good we are (or need to be) at
estimating probablilities - particularly probabilities of rare,
adverse events, and most particularly of rare, adverse events under
conditions where the recovery options are minimal. These obviously
include glides that cross unlandable terrain, final glides generally,
thermalling near mountain terrain, near clouds, under CB shelves, and
takeoffs and landings where there aren't a lot of "outs' for one
reason or another. I'm sure there are lots more. I've been wondering
about the idea of the right amount of margin and whether or not there
are sometimes circumstances where adding margin for one kind of bad
outcome reduces the margin for another (think of speed/height on final
versus the risk of under/overshoot at touchdown as one example).

If you are like me you carry margin around to deal with some estimated
probability of a bad event that is sufficiently out in the tail of the
probability distribution that we have it 99.99+% covered. But we all
come up with these estimates based on our experience, or maybe
observed experience of others. And in all likelihood we let our
margins erode if there is an incentive to do so and we don't directly
or indirectly have a sobering experience to drive us in the direction
of greater conservatism. I've seen enough cases of final glides gone
bad to add margin to account for a bit more in terms of adverse
circumstances but probably not enough for more than 1.5 miles with 20
knots of sink near the end. I tend to thermal at 70 knots near
mountain ridges (or not at all) and even so got a decent scare in a
low thermal that crossed to the downwind side of a spur of a ridge a
couple of years back.

I just wonder for how many of these rare acts of nature I have
significantly under-estimated, or do we all have to live with the idea
that bad luck can just come your way.

9B

On Thu, 15 May 2008 21:28:40 -0700 (PDT), CindyASK
wrote:


That was also the total gist of my presentation at the ABQ Convention,
titled "What the NTSB will Never Say About 2007 Fatalities."

Another fan of constructive speculation for personal-use accident-
analysis


I'd love to read it!
can you please send it to me?
thank you very much

Aldo Cernezzi
www.voloavela.it
nauta
-at-
email.it