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frankroskind(at)HOTMAIL.C
Guest

Posted: Mon Apr 27, 2009 7:26 am Post subject: New Zenith Statement

Does anyone know what the fracture patterns on the failed main spars looked like?  If aileron flutter were the cause C the fracture would have been because of a torsional stress C which might make stress lines with almost a circular pattern around the center of the spar.  If the failure were due to a single overstress C then we would see a single big tear C with few lines parallel to the final line of failure.  If the wing had a previous crack which grew C we would see a bunch of lines where small tears contributed to the final depth of the crack.  If we know how the spar failed then we can exclude some of the conjecture.

[quote] Date: Mon C 27 Apr 2009 11:01:04 -0400

 From: tigerrick(at)mindspring.com

 To: zenith-list(at)matronics.com

 Subject: Re: Zenith-List: Re: New Zenith Statement

 --> Zenith-List message posted by: Rick Lindstrom <tigerrick(at)mindspring.com>

 Sudden incapacitation comes to mind.

 Rick

 --

William Dominguez

Joined: 09 Apr 2008
Posts: 118

Posted: Mon Apr 27, 2009 7:35 am Post subject: New Zenith Statement

The use of the word "Large" or "small" is relative and subject to bias. The important piece of information is the answer to this question; how many other designs (with similar fleet size) have experimented 6 crashes due to wing failures in the last 3 years.



William Dominguez

Zodiac 601XL Plans

Miami Florida

http://www.geocities.com/bill_dom



--- On Mon, 4/27/09, Rick Lindstrom <tigerrick(at)mindspring.com> wrote:

[quote]

From: Rick Lindstrom <tigerrick(at)mindspring.com>

Subject: Re: Zenith-List: Re: New Zenith Statement

To: zenith-list(at)matronics.com

Date: Monday, April 27, 2009, 10:41 AM



--> Zenith-List message posted by: Rick Lindstrom <[url=/mc/compose?to=tigerrick(at)mindspring.com]tigerrick(at)mindspring.com[/url]>



Excuse me, Mike, but I have to ask.



Do you have ANY personal experience with this design, or the airplane itself?



You've posted some really outrageous statements, such as saying the airplane will disintegrate in mid-air if your cable tensions aren't perfect. Based on what evidence?



And now you're painting a picture that these crashes are endemic ("Bottom line is these accidents are HAPPENING, if wont matter what the cause is if you are in the airplane that breaks up in flight.") in spite of hard data to contrary. There have been six crashes over two years, with 10 fatalities, with a small variety of contributing factors suspected so far. You ignore the tens of thousands of successful flight hours racked up by the XL in its history, that debunk your claim of "...having a large number of structural failures,  and coming apart in flight."



And now you're insinuating that we don't care about "the dead guys." What nerve. Those of us who have built and fly the 601 are a family, after all, and we do care about each other. And like most families, we aren't shy about disagreements. How dare you insult the group like this? Are you one us, or just someone wading into the discussion from the outside just to stir up some crap?



What exactly are your motives here?



Rick



--

_________________
William Dominguez
Zodiac 601XL Plans
Miami Florida
http://www.geocities.com/bill_dom

d.goddard(at)ns.sympatico
Guest

Posted: Mon Apr 27, 2009 7:35 am Post subject: New Zenith Statement

Entirely possible of course, at any age. But it's another theory with no 

root in fact or knowledge, wasn't that one of the things we want to avoid?



Do Not Archive

---

tigerrick(at)mindspring.c
Guest

Posted: Mon Apr 27, 2009 7:51 am Post subject: New Zenith Statement

Exactly right!



There are many airplanes out there that have checkered accident histories, not because the design itself is flawed, but because they're easy to fly beyond design limits.



Toss in widely varying construction and maintenance quality, and who can precisely say?



I'm sure someone will jump in with the NTSB statistical averages here sooner or later...



Rick



do not archive



--

tigerrick(at)mindspring.c
Guest

Posted: Mon Apr 27, 2009 7:59 am Post subject: New Zenith Statement

That's why it only crossed my mind, along with all the other possibilities. Everyone wants to find a single causal "smoking gun", like aileron flutter, and move on. Yes, we do want to avoid wild speculation. However, we also shouldn't develop tunnel vision either, and be willing to at least consider other possibilities until all of the facts are in.



Rick



do not archive

--

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Mon Apr 27, 2009 7:59 am Post subject: Re: New Zenith Statement

 	  d.goddard(at)ns.sympatico wrote: 	
		  Entirely possible of course, at any age. But it's another theory with no 

root in fact or knowledge, wasn't that one of the things we want to avoid?



Do Not Archive

--- 	




That doesn't seem to be slowing down the NTSB. There was no sign of flutter in the Yuba City accident.



I agree that guessing sucks. But that is how the scientific process works. (See #3)



1. Ask a Question 

2. Do Background Research 

3. Construct a Hypothesis 

4. Test Your Hypothesis by Doing an Experiment 

5. Analyze Your Data and Draw a Conclusion 

6. Communicate Your Results

  



But the NTSB and others have skipped #4. I'm not even sure they spent that much time on #5.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

Juan Vega Jr

Joined: 13 Jan 2009
Posts: 157

Posted: Mon Apr 27, 2009 8:09 am Post subject: New Zenith Statement

Jay, 

i believe the accident cuased the two occupants to fly through window not before some kind of large negative g manauver cuased them to break the seat belt, tossing them through the wind shield out the plane.  That does not happen by a flutter, but by a violent stick movement exceeding -8 gs.  NTSB report does not say all the facts occuresd. Hientz Bros actually go to the accident scenes and check the scene along witht he NTSB.  NTSB reports dont always say all the details.



Juan



--

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Apr 27, 2009 8:29 am Post subject: Re: New Zenith Statement

 	  William Dominguez wrote: 	
		  The use of the word "Large" or "small" is relative and subject to bias. The important piece of information is the answer to this question; how many other designs (with similar fleet size) have experimented 6 crashes due to wing failures in the last 3 years.



William Dominguez



-- 	




William has got it right on, when you have 6 in flight breakups of a model of airplane in two years you have a PROBLEM.   Some dishonest people here that do not want to admit that their airplane may have a design flaw will try to distract others by saying, " People were not flying them right, or we don't know what caused it ".    It does not matter, Six in flight breakups in 2 years is UNACCEPTABLE, PERIOD.  This is NOT happening with other comparable LSA airplanes.



There are not that many Zodiac 601's out there flying that many hours.  This would be like having 100 Cessna 152's breaking apart in flight in two years, and then having a some fool saying,  " The pilots did not fly them correctly " or " Because we don't know for sure what caused it, there is no problem and we should not blame the airplane "..



Any honest and rational human without an agenda will see that six in flight breakups in two years is EXCESSIVE, especially considering the few number of these plane in service.  I have no use for dishonesty and denail.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

Last edited by JetPilot on Mon Apr 27, 2009 8:38 am; edited 1 time in total

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Apr 27, 2009 8:36 am Post subject: Re: New Zenith Statement

...

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

ggower_99(at)yahoo.com
Guest

Posted: Mon Apr 27, 2009 8:43 am Post subject: New Zenith Statement

--- On Mon, 4/27/09, Rick Lindstrom <tigerrick(at)mindspring.com> wrote:

 [quote]From: Rick Lindstrom <tigerrick(at)mindspring.com>

Subject: Re: Re: New Zenith Statement

To: zenith-list(at)matronics.com

Date: Monday, April 27, 2009, 10:41 AM

[quote]--> Zenith-List message posted by: Rick Lindstrom <tigerrick(at)mindspring.com>  Excuse me, Mike, but I have to ask.  Do you have ANY personal experience with this design, or the airplane itself?  You've posted some really outrageous statements, such as saying the airplane will disintegrate in mid-air if your cable tensions aren't perfect. Based on what evidence?  And now you're painting a picture that these crashes are endemic ("Bottom line is these accidents are HAPPENING, if wont matter what the cause is if you are in the airplane that breaks up in flight.") in spite of hard data to contrary. There have been six crashes over two years, with 10 fatalities, with a small variety of contributing factors suspected so far. You ignore the tens of thousands of successful flight hours racked up by the XL in its history, that debunk your claim of "...having a large number of structural failures, and coming apart in flight."  And now you're insinuating that we don't care about "the dead guys." What nerve. Those of us who have built and fly the 601 are a family, after all, and we do care about each other. And like most families, we aren't shy about disagreements. How dare you insult the group like this? Are you one us, or just someone wading into the discussion from the outside just to stir up some crap?  What exactly are your motives here?  Rick  --

ggower_99(at)yahoo.com
Guest

Posted: Mon Apr 27, 2009 8:48 am Post subject: New Zenith Statement

Hello Mike,

 

Very easy, just answer Rick with the Serial Number of you 601XL

 

Saludos

Gary Gower

601 XL   



--- On Mon, 4/27/09, Rick Lindstrom <tigerrick(at)mindspring.com> wrote:



From: Rick Lindstrom <tigerrick(at)mindspring.com>

Subject: Re: Re: New Zenith Statement

To: zenith-list(at)matronics.com

Date: Monday, April 27, 2009, 10:41 AM




<tigerrick(at)mindspring.com>



Excuse me, Mike, but I have to ask.



Do you have ANY personal experience with this design, or the airplane itself?



You've posted some really outrageous statements, such as saying the

airplane will disintegrate in mid-air if your cable tensions aren't perfect

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Mon Apr 27, 2009 8:56 am Post subject: Re: New Zenith Statement

It would only be like Cessna of the the 100 Cessnas were built in 95 different factories and most by people that never built a plane before and only a few of them were ever worked on by an A&P.



AVEMCO found that LSAs were twice as likely to have a claim as a conventional factory build SPAM can. But they also found that it wasn't because of any design or certification problem it was a training issue. The really interesting thing was that it wasn't that the pilots were inexperienced in general it was they they were not experienced in planes that were as agile as the LSA they had the accident in.



Let's put a few things we do know on the table.



1. There are lots of 601XLs flying lots of hours without a problem.



2. The NTSB and outside engineers have stated that the design exceeds the +4G design goal though one outside engineer says the plane may not quite make the +6 Ultimate goal.



3. If the plane makes the design goal (and there is no evidence to say it doesn't and there is evidence to say it does) then something is happening to make the aircraft exceed that limit or the plane wouldn't be breaking up in flight.



4. There is no physical evidence of flutter.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Mon Apr 27, 2009 9:05 am Post subject: New Zenith Statement

No, it would not be like having 100 Cessnas breaking apart in flight.  

Six is still a small number. I'm no expert at statistics, but even I  

know that it's not that simple. Simple linear interpolation doesn't  

work that easily when you go from a population of a few hundred to  

tens of thousands. It's very easy to skew the statistics all out of  

whack when you have such a small population to start with. it's  

entirely possible to toss a coin twenty times and get twenty heads or  

twenty tails. It's possible that we are just be seeing a short term  

aberration, even if it's not very likely.



On Apr 27, 2009, at 12:29 PM, JetPilot wrote:



 	  Quote: 	
		   



 William has got it right on, when you have 6 in flight breakups of a  

 model of airplane in two years you have a PROBLEM.   Some dishonest  

 people here that do not want to admit that their airplane may have a  

 design flaw will try to distract others by saying, " People were not  

 flying them right, or we don't know what caused it ".    It does not  

 matter, Six in flight breakups in 2 years is UNACCEPTABLE, PERIOD.



 There are not that many Zodiac 601's out there flying that many  

 hours.  This would be like having 100 Cessna's breaking apart in  

 flight in two years, and then having a some fool saying,  " The  

 pilots did not fly them correctly " or " Because we don't know for  

 sure what caused it, there is no problem and we should not blame the  

 airplane "..



 Any honest and rational human without an agenda will see that six in  

 flight breakups in two years is EXCESSIVE, especially considering  

 the few number of these plane in service.  I have no use for  

 dishonesty and denail.



 Mike



 --------

 &quot;NO FEAR&quot; -  If you have no fear you did not go as fast as  

 you could have !!!



 Kolb MK-III Xtra, 912-S




	


-- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Mon Apr 27, 2009 9:21 am Post subject: Re: New Zenith Statement

 	  ggower_99(at)yahoo.com wrote: 	
		  --- 



 ("Bottom line is these accidents are HAPPENING, if wont matter what the cause is if you are in the airplane that breaks up in flight.") in spite of hard data to contrary. There have been six crashes over two years, with 10 fatalities, with a small variety of contributing factors suspected so far.   Rick  -

	




The hard data is 6 in flight breakups in 2 years.  Other LSA designs, not even designs with much greater numbers produced, and flying many more hours  than the Zodiac 601 XL are NOT having in flight breakups.  That is the FACT...    So what is your " Hard Data to the Contrary " ???



Your assertion that anyone that does no fly a Zodiac 601 is not able to recognize that a very high structural failure rate is a problem is nothing short of stupid.  I do not have any flight time in the Zodiac 601, nor do I need any to know that 6 in flight breakups in a fleet size that small indicates a problem.  Again, there is you go trying to distract others away from the FACTS again.



In Jan 2009, about 360 Zodiac 601's had airworthiness certificates.  Six in flight breakups for a fleet this size is not typical, and not acceptable, PERIOD.   In 1985 when Cessna ended production of all of their light aircraft; by that time, a total of 7,584 examples of the 152 had been built, if the same percentage of 152's broke up in flight as Zodiac 601's have, that would have been 120 aircraft breaking apart in flight over the course of two years.  Yes, that percentage of the fleet breaking up in flight indicates a big problem, especially when it is NOT happening in other comparable airplanes.   



If I were not too deep into a Zodiac 601 right now, I would most defiantly be looking at other aircraft types.  The Sonex is an all metal, low wing airplane, that is faster, has a large number built and flying over the last 10 years, is aerobatic, and has had no in flight breakups even though there are a larger number of them now flying than the Zodiac 601.  Zenith Aircraft has never impressed me much with the design of their airplanes ( See my CH-701 to Kitfox Comparison ), this is just another example of why I would never consider any airplane from this company.



Mike

_________________
"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

William Dominguez

Joined: 09 Apr 2008
Posts: 118

Posted: Mon Apr 27, 2009 9:46 am Post subject: New Zenith Statement

A while ago I took the time to look for structural failure incidents in other popular experimental with with similar or larger fleet size than the Zodiac 601XL. Do you know how many cases I found? zero for Sonex, all KR models, 701, 601HD/HDS. 



The only design I found with several wing failure incidents was in one of the RVs models, 8 cases if I remember correctly. There are 2 important difference between the RV cases and the 601XL. First, in the RV cases, the NTSB where able to conclude that structural failure where the result of hard pulls by the pilot, as we know, all 601XL cases are inconclusive. Second, even thou the RV cases where concluded to be pilot error, Vans published a modification to beef up the spar and no more of this type of accidents have happened since.

William Dominguez

Zodiac 601XL Plans

Miami  Florida

http://www.geocities.com/bill_dom



--- On Mon, 4/27/09, Rick Lindstrom <tigerrick(at)mindspring.com> wrote:

[quote]

From: Rick Lindstrom <tigerrick(at)mindspring.com>

Subject: Re: Re: New Zenith Statement

To: zenith-list(at)matronics.com

Date: Monday, April 27, 2009, 11:50 AM



--> Zenith-List message posted by: Rick Lindstrom <[url=/mc/compose?to=tigerrick(at)mindspring.com]tigerrick(at)mindspring.com[/url]>



Exactly right!



There are many airplanes out there that have checkered accident histories, not because the design itself is flawed, but because they're easy to fly beyond design limits.



Toss in widely varying construction and maintenance quality, and who can precisely say?



I'm sure someone will  jump in with the NTSB statistical averages here sooner or later...



Rick



do not archive



--

_________________
William Dominguez
Zodiac 601XL Plans
Miami Florida
http://www.geocities.com/bill_dom

William Dominguez

Joined: 09 Apr 2008
Posts: 118

Posted: Mon Apr 27, 2009 10:10 am Post subject: New Zenith Statement

I need to make a correction to one of my statement bellow. When I said "as we know, all 601XL cases are inconclusive" this is not entirely correct. The wing failure incident in France was concluded to be a pilot error, he made a hard pull. We know because the pilot survived the incident by deploying a BRS system and he was interviewed by French investigators.

William Dominguez

Zodiac 601XL Plans

Miami Florida

http://www.geocities.com/bill_dom

--- On Mon, 4/27/09, William Dominguez <bill_dom(at)yahoo.com> wrote:

[quote]

From: William Dominguez <bill_dom(at)yahoo.com>

Subject: Re: Re: New Zenith Statement

To: zenith-list(at)matronics.com

Date: Monday, April 27, 2009,  1:39 PM



A while ago I took the time to look for structural failure incidents in other popular experimental with with similar or larger fleet size than the Zodiac 601XL. Do you know how many cases I found? zero for Sonex, all KR models, 701, 601HD/HDS. 



The only design I found with several wing failure incidents was in one of the RVs models, 8 cases if I remember correctly. There are 2 important difference between the RV cases and the 601XL. First, in the RV cases, the NTSB where able to conclude that structural failure where the result of hard pulls by the pilot, as we know, all 601XL cases are inconclusive. Second, even thou the RV cases where concluded  to be pilot error, Vans published a modification to beef up the spar and no more of this type of accidents have happened since.

William Dominguez

Zodiac 601XL Plans

Miami  Florida

http://www.geocities.com/bill_dom



--- On Mon, 4/27/09, Rick Lindstrom <tigerrick(at)mindspring.com> wrote:

[quote]

From: Rick Lindstrom <tigerrick(at)mindspring.com>

Subject: Re: Re: New Zenith Statement

To: zenith-list(at)matronics.com

Date: Monday, April 27, 2009, 11:50 AM



--> Zenith-List message posted by: Rick Lindstrom <tigerrick(at)mindspring.com>



Exactly right!



There are many airplanes out there that have checkered accident histories, not because the design itself is flawed, but because they're easy to fly beyond design limits.



Toss in widely varying construction and maintenance quality, and who can precisely say?



I'm sure someone will  jump in with the NTSB statistical averages here sooner or later...



Rick



do not archive



--

_________________
William Dominguez
Zodiac 601XL Plans
Miami Florida
http://www.geocities.com/bill_dom

jaybannist(at)cs.com
Guest

Posted: Mon Apr 27, 2009 10:11 am Post subject: New Zenith Statement

I recall a couple of certified aircraft (Robinson R22 and Mitsubishi MU2) having what was considered an excessive number of accidents.  In both cases, it was determined to be a problem of pilot training, not a design flaw.  Both manufacturers responded with more pilot training requirements and the problems all but disappeared.  All helicopters are demanding of pilot skill.   They are exceptionally vulnerable to pilot error that can cause it to fail structurally.  The same goes for the MU2. Does this mean there is something wrong with the MU2 and all helicopters that MUST be corrected by the manufacturers?  By the same token, how many certified airplanes come apart in flight when a pilot flies into meteorological conditions beyond the design of the airframe? Does this place the manufacturer or the designer at fault?  Steve Whittman lost his life when his own airplane came apart in the air d  ue to a construction error on his part.  Does that say that Whittman's design was at fault?  My point is that an aircraft designer has little control over how his design is used, or mis-used. With experimental aircraft, it is up to the builder to assure that it is built to the designers requirements; and it is up to the pilot of that aircraft to fly it within the designer's limitations.  The fact that it WILL exceed the designer's limitations is NOT a condemnation of the design.

 

 Jay Bannister

 

   

 

   

 

 --

JohnDRead(at)aol.com
Guest

Posted: Mon Apr 27, 2009 10:13 am Post subject: New Zenith Statement

Mike;

         Clearly you have an axe to  grind. Please go and do it somewhere else though. Your rhetoric is getting  tedious. WE DO NOT KNOW the cause of the 601 problem, so sit still, be quite and  stop pontificating on the "cause". Certainly we are concerned but conjecture is  just that. If you were not there you cannot possibly know the cause of the  problem. do not archive

  

 John  Read

CH701 - Elbert CO - Jabiru 3300



Phone: 303-648-3261

Fax:  303-648-3262

Cell: 719-494-4567   

  



 A Good Cr575x1220572846x1201387511/aol?redir=http://www.freecreditreport.com/pm/default.aspx?sc=668072&hmpgID=62&bcd=Aprilfooter427NO62>See yours in just 2 easy steps!

  [quote][b]

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Mon Apr 27, 2009 10:34 am Post subject: Re: New Zenith Statement

That's right on point Jay. The FAA even created a Special FAR for the required training, SFAR 74.



William, are you counting the low time, LSA pilot that broke up after taking off into IFR?

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

William Dominguez

Joined: 09 Apr 2008
Posts: 118

Posted: Mon Apr 27, 2009 10:56 am Post subject: New Zenith Statement

Mike,



Your problem seem to be beyond wing failure incidents. It seems like you made a mistake in your decision for some reason, and now you want to blame it on some external factors like wing failures and what not. 

William Dominguez

Zodiac 601XL Plans

Miami Florida

http://www.geocities.com/bill_dom



 	  Quote: 	
		  If I were not too deep into a Zodiac 601 right now, I would most defiantly be looking at other aircraft types.  The Sonex is an all metal, low wing airplane, that is faster, has a large number built and flying over the last 10 years, is aerobatic, and has had no in flight breakups even though there are a larger number of them now flying than the Zodiac 601.  Zenith Aircraft has never impressed me much  with the design of their airplanes ( See my CH-701 to Kitfox Comparison ), this is just another example of why I would never consider any airplane from this company.



Mike



--------

&quot;NO FEAR&quot; -  If you have no fear you did not go as fast as you could have !!!



Kolb MK-III Xtra, 912-S





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_________________
William Dominguez
Zodiac 601XL Plans
Miami Florida
http://www.geocities.com/bill_dom

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