Cirrus... is it time for certification review?

Recently, Stefan posted:

Neil Gould schrieb:

I can tell you there is little similarity between how the planes I've
flown stall or spin, though they are all basic SEL.

But all respond to the same technique of spin *recovery*, otherwise
they would not have been certified. (Only true for newer airplanes,
obviously.)

They all respond to different degrees to the same technique of spin
avoidance, but some have a lot more rudder or aileron authority than
others, and require different inputs after entry into a spin. At question
is what inputs are necessary to recover from a spin in a Cirrus?

Neil

Jose,

From googling this group, Ilan Reich, the accident pilot, was quoted
with a detailed account here. That contained the key sentence "On the
descent, I steered the plane clear of a fuel tank farm, and
crash-landed into the water near Haverstraw, NY.". It goes on to
describe in detail how he used throttle bursts to stear clear. The
"lucky oversight" was/may have been that he left the engine running
during chute activation, which is contrary to the recommended
procedure.

You were involved in that thread, too.

Yes, that is exactly what I meant.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

Jose,

Yes, that is exactly what I meant.


But the chute activation could have been followed by intentional engine
activation...

--
Thomas Borchert (EDDH)

But the chute activation could have been followed by intentional engine
activation...

Yes, it could have. My reccollection is that it wasn't. I remember
reading that the pilot had inadvertently neglected to turn off the
engine, and then used that fact to his advantage.

There's no windmilling prop if the engine is off, so starting it again
may not have been so simple.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

On Tue, 31 Oct 2006 01:20:54 GMT, Ken Reed wrote:

Actually both the Mooney and Bo are far easier to slow down even with
the tendency to float by the Mooney and they have roughly 30% less
wing loading than the SR-22.

Having owned both, I disagree. The Cirrus was easier to slow down than
my 'C' model Mooney. The only reason my 'M' model Mooney is easier to
slow down than the SR-22 is due to the speed brakes.

I've not flown all models of the Mooney but I stick with the statement
the one I flew was almost as easy to slow down as the Deb. The SR-22
was not. I'd not call the SR-22 difficult to slow down for an
experienced high performance pilot, but I would for a low timer.

When you stick the gear out the retracts feel like some one put the
brakes on. In a circle to land in the Deb you bring in about 23" OTOH
that is keeping it in close and tight turns. Turns are a really good
way to slow down about anything.


---
Ken Reed
M20M, N9124X
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Jose,

so starting it again
may not have been so simple.


Well, it always seems real simple when I do it before taxi ;-)

--
Thomas Borchert (EDDH)

I hate to tell you guys this but you better look more carefully. I am a
mechanical engineering student at a very well known and respected
engineering university (I won't comment on which one because I don't feel
it is ethically correct for this letter). I am currently working full time
in the field of mechanical engineering (not aeronautics yet) and I have
only begun to research a project for an engineering reliability report and
already some pretty clear facts are starting to pop up. It seems that
pilots enter turbulence or icing conditions and that starts to cause
delamination problems with Cirrus's high tech polymer/foam shell.
Hypothetically what might happen next is the pilots try like hell to get
the things under control while they are falling apart in the sky. Again,
hypothesizing, they might try rapid maneuver's to get the plane that is
now falling apart under control and end up stalling out the engine. They
are now completely losing it and instead of trying to glide down to a safe
height and speed to deploy the parachute they deploy at high altitudes and
speeds and the parachute rips away. Who knows maybe they can't get the
plane under enough control to safely deploy the parachute, after all, if
the plane is in the process of delaminating itself (i.e. layers of polymer
ripping away) maybe it is not possible. Now I am not a pilot and as I said
my report is not complete but I can tell you that maybe some people better
start asking the right questions like why is this thing delaminating under
mildly icy conditions. I mean most of these pilots in these accidents were
trying to get away from the clouds and some of them had the de-icing
option?????? Why have a de-icing option if it doesn't work - and
typically most mechanical designs are designed to fail slowly to allow
time to take alternative, life saving action. It seems this failure is
happening way too quickly and without enough of a safety factor for the
possible working environment. I personally love the look and the
"high-tech" of the plane but if I were a pilot this delamination thing
would have me spooked. You guys as pilots should really check out the
NTSB site (http://www.ntsb.gov) before forming an opinion. Of course, as
I said as an engineer I would decline to comment rather than get my rear
in a sling but, as a concerned citizen, you guys should do some more
research before endorsing this plane. Oh by the way the plane does have a
33% higher failure ratio than other planes in the competing class
(http://www.newsday.com/news/local/ne...-nynews-print).
Again, obviously I really don't know what I am talking about, this is not
an official statement, and all the other disclaimers I can possibly
include but just some information I thought you guys might want to know.

Anonymous Mechanical Engineering Student (senior)

Anonymous Engineering Student

____________________________________
Posted via Aviatorlive.com
http://www.aviatorlive.com

On Sun, 05 Nov 2006 22:24:05 -0600, "anonymousengineeringstudent"
wrote:

... Again,
hypothesizing, they might try rapid maneuver's to get the plane that is
now falling apart under control and end up stalling out the engine.
^^^^^^^^^^^^^^^^^^^^^^^^
You do realize this costs you any credibility about aeronautical matters, right?

I personally love the look and the
"high-tech" of the plane but if I were a pilot this delamination thing
would have me spooked. You guys as pilots should really check out the
NTSB site (http://www.ntsb.gov) before forming an opinion.

I used the NTSB accident page to run a search for Cirrus accidents where the
words "delaminate", "delamination," or "delaminated" appear. I found just one
hit (DEN06FA114) where, by the context, it appears that the parts delaminated on
impact.

In which other accidents did delamination occur?

Ron Wanttaja

...turbulence or icing conditions and that starts to cause
delamination problems with Cirrus's high tech polymer/foam shell.

Cite? Upon what do you base these "pretty clear facts"?

and end up stalling out the engine.

What does the wing delaminating have to do with the engine? And what
does "stall" mean in this context?

To a pilot, these words have different meanings.

Oh by the way the plane does have a 33% higher failure
ratio than other planes in the competing class...

Newsday is hardly a reliable source of engineering statistics. And for
an engineering student at a well known and respected university to use
"33% higher failure ratio" (with no numerator or denomenator specified)
is exceptionally sloppy. Perhaps you mean "rate", in which case you
still need to specify "per what" if you want to say something meaningful.

I suspect you mean well, but more care in your dissertation would be
appropriate here.

Jose
--
"Never trust anything that can think for itself, if you can't see where
it keeps its brain." (chapter 10 of book 3 - Harry Potter).
for Email, make the obvious change in the address.

anonymousengineeringstudent wrote:
I am a mechanical engineering student at a very well known and
respected engineering university (I won't comment on which one
because I don't feel it is ethically correct for this letter).

If there's a Computer Science department at your school, or an IT
department that runs the school's computers, you probably want to talk
to them. They should be able to tell you ways to post to Usenet that
can help hide the fact that you're probably posting from a Comcast
cable modem in New Jersey, 68.46.165.176 or
c-68-46-165-176.hsd1.nj.comcast.net .

I am currently working full time in the field of mechanical
engineering (not aeronautics yet) and I have only begun to research
a project for an engineering reliability report and already some
pretty clear facts are starting to pop up.

Assuming for the moment that you are in New Jersey: Both Princeton and
Rugters list departments or degree programs in "mechanical and aerospace
engineering", which is a slightly different phrasing than "aeronautics".
NJIT and Stevens simply call their programs "mechanical engineering".
Of course, you could be attending some other school in New Jersey, or a
school in a nearby state. Or, maybe you aren't in or near New Jersey at
all.

Organization: Aviatorlive.com

This site appears to be a sponge site, that is simply a "Usenet for
dummies" web gateway to r.a.p, plus the obligatory Google ads. Running
a search on that site does find your post, but because of the completely
broken threading in the web interface, it won't actually pull up there.

Headers as received he

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Subject: Cirrus... is it time for certification review?
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Matt Roberds