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AOPA Stall/Spin Study -- Stowell's Review (8,000 words)



 
 
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  #21  
Old September 3rd 03, 02:34 AM
G.R. Patterson III
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Roger Long wrote:

I've had good luck doing the power thing with 40 degree flaps, arresting the
descent more with a burp of power than flare. Of course, if you got to that
point and discovered that your engine was just windmilling on you, you'd
probably make a spectacular bounce.


Never happen with my Maule. Anything below 1.3 with full flaps requires back
pressure on the yoke and some power. There's no way you'll fly final at, say,
55 mph with a windmilling engine and not know it.

George Patterson
A friend will help you move. A really good friend will help you move
the body.
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  #22  
Old September 3rd 03, 12:43 PM
Roger Long
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Come to think of it, that may be true of the 172 also. I usually fly short
final at 1500 RPM and go to idle crossing the numbers. I think I often put
in a bit of power with the last notch of flaps to set a good descent rate.
At this point, I'm not paying much attention to numbers but flying by the
windshield. I do keep an eye on the airspeed however.

If the engine quit, it would probably be pretty evident by the far end of
the runway disappearing behind the sun visors and a dramatic descent rate if
you kept the airspeed up. That would still be pretty exciting if you
weren't paying attention. Maybe that's why the lawyers made Cessna reduce
maximum flaps to 30 degrees.

Back when I was still learning to land, the steeper my descent, the better
my touchdowns. I gather the reverse is true for most people.

--
Roger Long


  #23  
Old September 3rd 03, 04:01 PM
G.R. Patterson III
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Roger Long wrote:

If the engine quit, it would probably be pretty evident by the far end of
the runway disappearing behind the sun visors and a dramatic descent rate if
you kept the airspeed up.


Actually, the descent rate would be most dramatic if I kept the airspeed down.
In my aircraft, the ROD increases dramatically below 57 mph.

My best chance of making the field would be to raise the flaps, lower the nose,
and get the speed up to 80 mph.

George Patterson
A friend will help you move. A really good friend will help you move
the body.
  #24  
Old September 9th 03, 04:02 PM
Rich Stowell
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In the interest of fairness, following is the AOPA ASF response to my
review. All of this, including the link to the original study, is
posted on my web site as well at http://www.richstowell.com/aopa.htm:


-------START-------

September 8, 2003

Dear Rich:

Thanks for your review of ASF's report on the role of stall/spin
accidents in general aviation. Having an extra voice on the subject -
especially from a respected unusual attitude trainer like yourself -
can only help in our common mission of educating pilots and improving
the GA accident rate.
Reading through your comments, it sounded a bit adversarial in places
and yet we agree on many points. In the very first paragraph, you
accuse ASF of fabricating a myth [ Pilots who believe that aerobatic
training will enable a recovery from an inadvertent spin in the
traffic pattern are fooling themselves. ] solely for this study. To
provide a more balanced viewpoint, you might also have quoted the next
few sentences "This study is not intended to discount the value of
properly conducted aerobatic and spin training. Training in a
controlled environment with a trained instructor is beneficial. The
most important aspect of the training should be recognition and
prevention."

That doesn't sound like we ".essentially missed the point of spin
training."

Regarding the myth, I'd suggest that the reason you hadn't heard it
is that it exists mostly among the pilots you HAVEN'T been associating
with - those who haven't sought out spin training, and who aren't
professional spin or aerobatic instructors. The pilots who subscribe
to this myth are among many all over this country who pick up much
incorrect information in the process of hangar flying. They may be a
minority, but minorities are precisely the ones who make the accident
statistics, but let's get to some of your key points.

"The study claims that this myth ("watch your airspeed, or you're
going to stall this airplane") is largely propagated by flight
instructors...."

We agree that it IS largely propagated by flight instructors. It was
nice of you to add that many of those instructors are low-time,
under-trained and/or under-informed, but that's something we've agreed
upon in the past and continue to do so. We also clearly laid out the
true path to safety lies in the angle of attack.

"AOPA has been known to disseminate stall/spin mythology as well."

We did explore the possibility of proving (or disproving) the
statement that more pilots were killed in spin training accidents than
in real emergencies. That information was provided by several FAA
officials, who believed that to be the case. We couldn't prove that,
either way, if the "more" was correct. There were certainly training
accidents, however. Older NTSB records were only recently made
available online, and even then only back to 1962. Again, you left
out context by not quoting the sentence preceding, " Because of
improved aerodynamics and an emphasis on avoidance, the number of
spin-related accidents has dropped significantly."

"I believe... however, that... in exchange for relaxing spin training
and aircraft spin certification requirements, manufacturers were to
develop more spin resistant designs. Manufacturers have largely failed
to live up to their end of the bargain."
We agree again and it's right there in the ASF study: "Officials at
the time also reasoned that if there was no spin requirement for
private pilots, then aircraft manufacturers would also be encouraged
to produce aircraft with greater spin-resistant characteristics." In
addition, ASF's new premier live seminar on Maneuvering Flight (which
will debut at AOPA Expo in October and will run through the first half
of 2004 nationwide) uses a NASA study and other evidence to clearly
establish that not everything possible has been done through aircraft
engineering to minimize stall/spin accidents.
There is some movement in that direction recently with the
certification of spin resistant aircraft and your own point, that one
reason for the drop in accidents was that newer aircraft introduced in
the 50's and beyond were somewhat more spin resistant. So technology
does make a difference, perhaps more reliably than other methods. By
the way, in the seminar we recommend that if pilots elect to take
unusual attitude and spin training, that they go to professionals like
you who have the expertise and the equipment to do the job safely.

"Of interest is AOPA's conclusion that "it appears that ATP's are
generally the most experienced and knowledgeable pilots, while
students are under very close supervision to ensure their safety."

The additional study of ATP stall/spin accident rates in your report
certainly is interesting, but it only confirms ASF's original
conclusion that private and commercial pilots were the groups most in
danger of a stall/spin accident. We did NOT look at aerobatic
involvement.
"If the reason Student pilots have a 4 percent stall/spin fatality
rate is due to "very close supervision to ensure their safety" as
concluded in the AOPA study, then wouldn't it follow that flight
instructors would also have a comparably low stall/spin fatality
rate?"

Students, by regulation, are required to have very close supervision
in all phases of training leading up to the private pilot certificate.
Regarding CFI's being as safe, No, not necessarily. It is the CFI's
doing the supervising for solo students and they appear to apply
different standards to themselves when in a dual flight situation.
As the ASF study points out, the numbers involved are fairly small: a
total of only 44 fatal stall/spin accidents in an instructional
setting over a 10-year period. That the majority (91%) happened with
CFIs on board may very well be due to insufficient spin training of
CFIs today, as those CFIs provide dual instruction in some of the most
risk-prone corners of the flight envelope.
"(The decrease in stall/spin accidents after 1949) myth attempts to
create a non-existent cause-and-effect relationship."
Not quite sure what you're saying here, but there is no myth that spin
accidents when down, coincident with the deletion of the spin demo
requirement. We absolutely agree this was also influenced by multiple
factors previously mentioned.
Aviation accident investigation and reporting not only isn't an exact
science, but (as we all agree) has changed and evolved over the years.
Your report on the ASF study points out quite correctly that many
factors could be involved in the decrease in the number of stall/spin
accidents since deletion of the spin requirement from the private
pilot certificate in 1949, including changes in training and testing,
training methodologies, aircraft engineering and other things. Even
definitions of accident causes have evolved over the years, further
muddying the water. But on its most essential level, NTSB accident
reports clearly show that GA accidents due to stalls and spins have
indisputably decreased over the years.

"The discussion of altitude losses during stalls and spins referenced
in the AOPA study lacks context; the information as provided,
therefore, is misleading."

No, all the context is there, including the sources for data ASF used
in the study. In the case of average altitude loss during stalls, we
used the best available information from the manufacturers. Most
pilots understand that professional test pilots using new aircraft
conduct these tests, and that the individual pilot's mileage may vary,
usually in the direction of more, rather than less, altitude loss. Is
there a CFI anywhere who has not warned students, "give yourself some
margin when calculating aircraft performance?"
For other aspects of altitude losses, we used the best available data
from extensive FAA and NASA tests, as well as an in-depth study of our
own GA Accident Database. Bottom line - the numbers in the POH are
the basis upon additional decisions should be made. You have to start
somewhere and this conversation proves our point - recovery from a low
altitude spin is unlikely.

"Here, too, the AOPA study misleads readers regarding so-called
significant differences between Tomahawk and Cessna 150/152 spin
behavior."

We've been down this road before, and our conclusion that the Piper
Tomahawk is NOT a particularly dangerous airplane when properly flown
stands. It does have spin behavior that - while meeting FAA
certification standards - is not as docile as most, other training
aircraft, but that in itself doesn't make it dangerous. As with many
aviation safety issues, it's the pilot who makes the difference,
especially when dealing with matters of aircraft design.
Since our last go-around on this issue, we've been watching the
accident record for Piper Tomahawks very carefully to see if your
concerns about the design could be validated. So far, they can't: the
last stall/spin accident involving a Tomahawk was in 1999, near
Warrensburg, Illinois. The aircraft had been loaded nearly 100 pounds
over its maximum gross weight, which the NTSB cited as a contributing
factor. If there was a systemic problem I believe we'd see more than
one accident in 4 years. Will there be another PA38 spin accident in
the future? Probably, which will raise all the old arguments but
pilots do have to understand the nature of their machines. Occasional
individual failures, as tragic as they may be, do not show
non-compliance with certification rules. It shows that some aircraft
are not as docile as others in certain flight regimes. Your original
position, as I recall was that the Tomahawk was a dangerous aircraft.
ASF's consistent position is that this aircraft, like many, that has
some different traits that pilots should be aware of.
We'd also direct your readers to my feature article that appeared in
February '03 AOPA Pilot - Spinning In -
http://www.aopa.org/asf/asfarticles/2003/sp0302.html. It reviews some
of this history, interesting NASA research and of the challenges of
educating pilots in spin resistant aircraft. Like any airplane, they
shouldn't be flown contrary to explicit warnings in the POH.
Rich, I'd like to thank you for your analysis of the ASF study,
because it provides solid additional information that - for the most
part - reinforces the conclusions in the ASF study. There are some
points that were taken out of context, but generally, we agree. I also
remind your readers that we are proponents of quality unusual attitude
training as stated in the opening paragraph of the study.

Safe Flights,

Bruce Landsberg
Executive Director
AOPA Air Safety Foundation

-------END---------
  #25  
Old September 9th 03, 06:00 PM
Morgans
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"Rich Stowell" wrote in message
om...
In the interest of fairness, following is the AOPA ASF response to my
review. All of this, including the link to the original study, is
posted on my web site as well at http://www.richstowell.com/aopa.htm:


Dead link


  #26  
Old September 9th 03, 08:28 PM
Aardvark
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Morgans wrote:
"Rich Stowell" wrote in message
om...

In the interest of fairness, following is the AOPA ASF response to my
review. All of this, including the link to the original study, is
posted on my web site as well at http://www.richstowell.com/aopa.htm:



Dead link


Live link
http://www.richstowell.com/aopa.htm


WW

  #27  
Old September 10th 03, 12:23 AM
Rich Stowell
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"Morgans" wrote in message ...
"Rich Stowell" wrote in message
om...
In the interest of fairness, following is the AOPA ASF response to my
review. All of this, including the link to the original study, is
posted on my web site as well at http://www.richstowell.com/aopa.htm:


Dead link



Try this:

http://www.richstowell.com/aopa.htm

(the colon I added at the end of the line was mistakenly treated as
part of the hyperlink...)
  #28  
Old September 11th 03, 01:27 PM
Neil Gould
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Recently, Rich Stowell posted:

While not exactly covering the breadth of the issue, this portion is dear
to my heart:

"Here, too, the AOPA study misleads readers regarding so-called
significant differences between Tomahawk and Cessna 150/152 spin
behavior."

We've been down this road before, and our conclusion that the Piper
Tomahawk is NOT a particularly dangerous airplane when properly flown
stands. It does have spin behavior that - while meeting FAA
certification standards - is not as docile as most, other training
aircraft, but that in itself doesn't make it dangerous. As with many
aviation safety issues, it's the pilot who makes the difference,
especially when dealing with matters of aircraft design.
Since our last go-around on this issue, we've been watching the
accident record for Piper Tomahawks very carefully to see if your
concerns about the design could be validated. So far, they can't: the
last stall/spin accident involving a Tomahawk was in 1999, near
Warrensburg, Illinois. The aircraft had been loaded nearly 100 pounds
over its maximum gross weight, which the NTSB cited as a contributing
factor.
(rest snipped for brevity)

Much of my early training was in a Tomahawk. My first attempt at a stall
resulted in a spin. It was... exhilirating... but no big deal to recover
from. Having been provided with many alarmist documents about the dangers
of spinning in a Tomahawk, I researched the matter thoroughly, both
theoretically and in practice. The conclusion that I reached is similar to
the above: to get into trouble, you have to load the Tomahawk pretty far
out of the w/b envelope, and that isn't easy to do.

My instructor and I, along with a full load of fuel, amounted to being in
the same 100 lbs over max gross weight as the above example, and that was
our typical configuration at take-off. However, while overweight, we were
*not* out of balance, and thus all manoeuvers were predictable and
controllable.

To get out of balance, you have to be a light-weight pilot and have some
serious weight (exceeding the posted max load) in the baggage area. Anyone
that could do such a thing is probably pretty dangerous in other regards,
as well, so it would be difficult to pin any consequent difficulties on
the design of the aircraft.

The worst thing that I can say about a Tomahawk in comparison to the
Cessnas is that you have to *fly* the plane at all times... it won't fly
itself for long. I think that makes for a great trainer.

Neil


  #29  
Old January 2nd 09, 03:26 PM
Jim Wills Jim Wills is offline
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Posts: 1
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Quote:
Originally Posted by Chris Hoffmann View Post
The first thing that jumped out at me from your report is this:

Another myth cited in the AOPA study is "watch your airspeed, or
you're going to stall this airplane!"


Pardon me, but if your airspeed gets below stall speed, you ARE going to
stall. Further, if your airspeed is below the usual 1.3 Vso safety cushion,
you are getting to the point where all it takes is a turn too steep, or a
bit of tailwind, or a yank back on the yoke, and you are LIKELY to stall.
This is not "myth".
snip
I was fortunate enough to have taken Rich's EMT training twice many years ago. "Stall speed" as noted in the POH for your airplane really means "stalling speed at 1G". The wing can stall, or not stall, at any speed down to zero - it depends on the AOA and nothing more. Think about a hammerhead turn: you go vertical, and at the top the wing has a nearly zero speed, but also a nearly zero AOA, so it doesn't "stall" and then nose over to the front.
 




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