---------------------------------------------------------- Zenith-List Digest Archive --- Total Messages Posted Sat 03/07/09: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:55 AM - Re: Re: crash B.S. (=?iso-8859-1?Q?Fran=E7ois_CHAPPERON?=) 2. 04:36 AM - Re: Re: crash B.S. (Paul Mulwitz) 3. 05:48 AM - Re: Re: crash B.S. (Dave Austin) 4. 12:20 PM - Re: Re: crash B.S. (Afterfxllc@aol.com) 5. 12:22 PM - Re: Re: crash B.S. () 6. 12:56 PM - Re: Re: crash B.S. (LarryMcFarland) 7. 01:06 PM - Re: Re: crash B.S. (Dave) 8. 01:52 PM - Antennas (Bill Naumuk) 9. 02:09 PM - O-200 Electronic Tacho (Peter W Johnson) 10. 03:13 PM - Re: O-200 Electronic Tacho (Sabrina) 11. 04:17 PM - Re: Antennas (Lawrence Webber) 12. 08:36 PM - Re: Lightning holes flange dies & sizes (Lee Steensland) ________________________________ Message 1 _____________________________________ Time: 12:55:12 AM PST US From: =?iso-8859-1?Q?Fran=E7ois_CHAPPERON?= Subject: Re: Zenith-List: RE: crash B.S. Hello all of you over the Atlantic ocean ! I react to Paul Mulwitz post. because he is speaking of what is happening in Europe and I=92m living in France with my 601xl built from a 100% kit . I already introduced myself to you last year. It=92 is right Dutch authorities decided ( maybe too quickly)to stop flights with 601; In the same time, German people did the same , a few weeks ago ! they have considered, exactly as you said, that. Design sounds good and number of 601 flying world wide a kind of proof. However, they said that dynamic tests were not run and that is not correct .. So you must know that last week , ZENAIR FRANCE (Michael Heintz) sent a 601XL to a private laboratory in HAMBOURG (Germany) to have dynamic examination in an artificial speed room ( blowers) They also asked ZENAIR to have a dynamic =93g=94 test by loading wings , both sides, (intrados and extrados) with a charge of sand sacks . So you see that tests that were never ran in the past are going to be done! All buzz will stop that day ! Be sure that ZENAIR EUROP will communicate the very results if they are positive Be sure German authorities will communicate the very results if they are negative ! Yours, Fran=E7ois Chapperon 407 r=E9duite_modifi=E9-1 ________________________________ Message 2 _____________________________________ Time: 04:36:04 AM PST US From: Paul Mulwitz Subject: Re: Zenith-List: RE: crash B.S. Bon jour Francois, Thank you for writing to announce the dynamic testing in Germany. Also, I thought Michael Heintz was in California and Nicholas and Chris were in Europe. Those guys move around very quickly. My understanding of dynamic testing is different from your description. As I understand it, vibrations are introduced into various parts of the airframe. The hope is to find a particular vibration frequency and location that becomes resonant. This makes the amplitude of the vibration much larger and can lead, very quickly, to structural failure. The problem with this type of test is the number of different vibration frequencies and locations for introducing the vibrations is nearly infinite. That makes this kind of testing very difficult and expensive. It is done (required?) for many certified aircraft, but not usually done for experimental ones. I am not familiar with the wind tunnel testing you described. It sounds like a good idea, but I have no idea what sort of issues it examines. Perhaps this is a way to look at the possibility of control flutter. I believe the sand bag loading test is called static testing. This kind of test has been performed at least twice on the American version of the Zodiac XL. I don't know if it has been done on the European version at all. I am glad to learn there are competent people still looking for true explanations for the problems with the XL. I will be flying mine very soon (a month or two?) and don't expect to have any problem. Still, I am concerned that there might be a very small chance for a very big problem. Best regards, Paul XL getting close At 12:51 AM 3/7/2009, you wrote: >Hello all of you over the Atlantic ocean ! > > >I react to Paul Mulwitz post. because he is >speaking of what is happening in Europe and I=92m >living in France with my 601xl built from a 100% kit . > >I already introduced myself to you last year. > > >It=92 is right Dutch authorities decided ( maybe >too quickly)to stop flights with 601; > >In the same time, German people did the same , a >few weeks ago ! they have considered, exactly as you said, that. > > >Design sounds good and number of 601 flying >world wide a kind of proof. However, they said >that dynamic tests were not run and that is not correct . > > >So you must know that last week , ZENAIR FRANCE >(Michael Heintz) sent a 601XL to a private >laboratory in HAMBOURG (Germany) to have dynamic >examination in an artificial speed room ( blowers) > >They also asked ZENAIR to have a dynamic =93g=94 >test by loading wings , both sides, (intrados >and extrados) with a charge of sand sacks . > > >So you see that tests that were never ran in the >past are going to be done! All buzz will stop that day ! > > >Be sure that ZENAIR EUROP will communicate the >very results if they are positive > >Be sure German authorities will communicate the >very results if they are negative ! > > >Yours, > > >Fran=E7ois Chapperon > > >407 r=E9duite_modifi=E9-1 ________________________________ Message 3 _____________________________________ Time: 05:48:50 AM PST US From: "Dave Austin" Subject: Re: Zenith-List: RE: crash B.S. Could we give this subject a rest, please. And don't forget the do not archive, because we won't want to go searching this stuff anytime. Dave Austin 601HDS - 912 ________________________________ Message 4 _____________________________________ Time: 12:20:36 PM PST US From: Afterfxllc@aol.com Subject: Re: Zenith-List: Re: crash B.S. Take me with you this is getting old. Oh, boy. Here we go again. I'm going out flying to get away from all this. **************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! %3D62%26bcd%3DfebemailfooterNO62) ________________________________ Message 5 _____________________________________ Time: 12:22:10 PM PST US From: Subject: Re: Zenith-List: Re: crash B.S. Rhino, they may have something there. The fact that there were tire marks on one wing suggests that the wing may have folded down in flight. The only way I can think to explain that one is that the plane may have experienced a violent updraft, followed by one hellacious downdraft. My thinking is that at the top of the updraft, and at the moment of entering the downdraft, the inertia of the fuselage would have been to continue up, while the downdraft was acting on the wings. Just a thought. I seem to remember something similar happened to some T-28s a long time ago. Paul Rodriguez DO NOT ARCHIVE ----- Original Message ----- From: Rhino To: zenith-list@matronics.com Sent: Friday, March 06, 2009 4:59 PM Subject: Zenith-List: Re: crash B.S. > jmaynard wrote: > On Fri, Mar 06, 2009 at 12:38:38PM -0500, Juan Vega wrote: > > > Lets start looking at the facts, that most to all the accidents are due to > > pilot or maintenance issues. You guys that keep hunting for a problem > > after it is stated over and over again there is no design problem, need to > > find something else to do like go hunt for UFOs in the desert. My brand > > of BS smells more like perfume when compare to the BS you guys are dishing > > out over the wrong thing. > > Juan, you keep ignoring N158MD. How does that accident fit into your view? I can't speak for Juan, but N158MD seems to fit perfectly into what he said. > While cruising toward Willows, about 10 minutes after takeoff and 16 miles west of Lincoln, five ground-based witnesses heard the airplane. Two of the witnesses also observed the airplane prior to the breakup. > > In summary, three of the auditory witnesses reported hearing a "bang" sound. One of these witnesses reported that for about 10 seconds prior to hearing the "bang," the engine was misfiring or sputtering. The sound increased in loudness and ended with a loud "bang." > > The fourth witness reported to a Sutter County Sheriff's deputy that he had been working in his field when he heard an airplane overhead. The witness opined that the airplane's engine was missing really badly. A few seconds later, as he was looking at it flying an estimated 800 to 1,200 feet above ground level, the airplane "blew up." The wings flew off, parts went everywhere, and the cockpit turned in circles as it descended. > > The fifth witness reported to the Safety Board investigator that he was a retired United States Air Force mechanic and was familiar with light airplanes. The witness was standing outside his residence, about 0.5-mile southeast of the accident site. In summary, the witness reported that he heard the sound of the airplane's engine, and it sounded fine. It was operating smoothly, its rpm sounded steady in that it was producing a constant tone, and it was not backfiring or sputtering. Then, the witness looked upward in the direction of the engine sound and immediately observed the airplane. The airplane was northwest of his location, and it was cruising in a northwesterly direction. Its wings were level. The airplane was not turning, climbing, or descending. The witnesses further stated that he could clearly see the airplane and saw no evidence of fire or smoke trailing from it. > > The fifth witness additionally reported that, after a few seconds, he stopped looking at the airplane and started talking on his cell phone. The witness estimated that he looked away from the airplane for about 5 seconds. Then, he heard the sound of the airplane's engine rapidly change rpm. Within about 0.5 seconds, it decreased and then increased, as if the pilot had retarded the throttle and then suddenly changed his mind and restored the power. When the rpm came back up, it did not sound like the engine had over revved. The tone sounded the same as before the power had decreased. The witness reported that immediately after the engine power came back up, he heard the sound of an explosion, which was followed by the sound of metal scraping. > > Thereafter, he saw what he believed were three distinctive large components falling. The components were the wings and the fuselage. The witnesses stated that it took perhaps 6 to 8 seconds for the airplane to fall, and it fell straight down. As the components descended, the fuselage spiraled around. There was no fire or smoke. > > The witness opined that, originally, he thought there had been a mid-air collision. However, there was no other aircraft in the area. http://www.ntsb.gov/ntsb/GenPDF.asp?id=LAX07FA026&rpt=fa The aircraft actually took off 78 pounds over gross and was about 68 over when it crashed, but I don't see that as a factor. All witnesses reported the aircraft in level or near level flight when the accident occurred. If the airframe failed due to some design deficiency, then why did both the wings and stabilizer fail downward instead of upward? In level flight, natural forces push those surfaces up, not down. Indeed, the left wing even had a tire mark on it's underside from striking the landing gear. Several of the witnesses strongly indicated engine trouble prior to the breakup. This is a double edged sword though. While engine trouble may have been the catalyst for this event, it is unlikely that an engine problem would create an explosion of a magnitude that would cause the aircraft to break up. On the other hand, some types of dramatic engine failures have resulted in major changes to the flight characteristics of some aircraft. Such changes could conceivably cause the aircraft to transition into an attitude that created forces beyond it's design limits. It is also possible that a pilots reaction to a sudden problem caused him to inadvertently do the same thing. Both of those types of scenarios have happened before. Teledyne Continental Motors (TCM) reported that AMD had made modifications to the O-200 engine that were contrary to TCM's tested design and TCM had never tested the engine with AMD's modifications. I tend to doubt that's very relevant. The nature of those mods don't suggest a catastrophic failure. The owners had replaced a magneto without documenting it. The new magneto timing was found to be 32 degrees BTDC instead of the required 28. The starter was an aftermarket accessory whose installation was also not documented. The gasket for the starter was not properly. The drive coupling was noted to be loose, and actually fell out when they removed the starter. This alone does not look to have been a factor in the crash. TCM found that a required starter adapter plug assembly had inadvertently not been installed when the engine was manufactured. It is designed to keep oil out of an area of the engine where it is not desired, essentially the area of the starter. TCM said that would not have caused anything more than a leak around the starter, possibly made worse by the improper starter installation mentioned above (the engine was not oil starved at the time of the crash). TCM later admitted that they had detected the oil leak during initial testing of the engine during manufacture, and that they were responsible for the improper starter installation. There was a gear tooth broken off in the crankshaft assembly, but it appeared to have occurred on impact. One of the aircraft owners reported that they sometimes noticed an unusual vibration in the floor area of the cockpit. The report makes no significance of that, but it does make me go hmmmm. Now for the meat of the issue. The right and left wing rear spar attachment plates, the rear spar root doublers, the wing rear channel (spar), the center spar web, front and rear, the center spar cap (main wing spar), center section; and the rear spar attachment for the stabilizer. were measured to determine conformity with construction specifications. The thickness measurements of all examined components were found consistent with the design specifications. No anomalies were noted by the Safety Board investigator or the AMD participant. That means that the previously tested, proven and approved design limits were present in the construction of the crashed aircraft. The aft 4 feet of the airplane's rear empennage, horizontal stabilizer with attached elevator, vertical stabilizer, rudder, and the left aileron were examined by a metallurgist from the Safety Board. The metallurgist did not report finding any evidence of preimpact cracking or damage in any of the examined parts. In other words, there was no evidence of an inflight breakup of the horizontal stabilizer. And finally, the airplane's entire structure was examined by an aerospace engineer from the Safety Board. The engineer reported that all of the fracture surfaces examined exhibited features consistent with static overload. In other words, they happened as a result of stresses beyond the design limits of the aircraft, which means there was no design deficiency that caused the breakup. All breakups, fractures, etc were caused by the aircraft exceeding the design limits after whatever unknown factor initially caused the accident scenario to unfold. In the end the NTSB determined "In-flight structural failure of the horizontal stabilizer and wings for undetermined reasons." It says undetermined for a good reason, because they have no evidence to indicate a specific reason, to include a design deficiency. On the contrary, their investigation very strongly indicates that there was no design deficiency at all related to this crash. With zero evidence to indicate a design deficiency in this crash, or in any other 601 crash for that matter, it really isn't necessary for Juan to explain how N158MD fits into his view. Is it possible that that particular aircraft crashed due to some construction deficiency? Sure it is, but none of the evidence points to that, and a lot of the evidence seems to preclude it. Notice that I said it was possible that it crashed due to some construction deficiency, not a design deficiency. If there was indeed such a design deficiency in the 601, the NTSB would certainly have at least hinted at it. And such a deficiency would almost certainly have shown up loooong ago when you consider how many of them are flying. Anyone can opine that there is some very minute possibility of a heretofore unknown design deficiency. But if we really want to venture into the realm of very minute possibilities then we could also opine that the aircraft could have been struck by a meteorite. There's a big difference between making a wild guess and claiming something as true or even probable. It's even a good idea to ask if you think something is true or even probable. But to claim something as true or even probable without some definitive or even remotely associated evidence is quite rightly going to make you subject to disagreement. It is also difficult to raise an incident as evidence of your cause, when the true facts of that incident seems to prove the opposite of what you claim. When it all boils down to it, anybody is free to believe whatever they want. It just saves everyone grief and frustration if people don't claim something as fact when they have no evidence of that. No, jmaynard, I'm not saying you are specifically doing that. It just seems to be an underlying train of thought for some people in discussions like this. -------- Bob Simmons CH 750!!! N750TN (reserved) Read this topic online here: http://forums.matronics.com/viewtopic.php?p=233521#233521 http://www.matronics.com/Navigator?Zenith-List http://www.matronics.com/contribution ________________________________ Message 6 _____________________________________ Time: 12:56:08 PM PST US From: LarryMcFarland Subject: Re: Zenith-List: Re: crash B.S. Exactly right Andrew, The discussion of this problem is painful for most posters XL builders and owners, but it will run on until statistic or proofs resolve the issue. I built a revision 4 HDS that was much heavier than the first edition HDS that first flew with a Rotax 583 at a 580 lb empty wt. The HDS has been progressively upgraded and strengthened by thicker materials to use larger engines, presumably to fly faster, but as a drawing set, revision 4 HDS is still a very light aircraft by comparison to RV and others. The newer XL at first glance with a reduction of wing thickness and flaps assured a way to fly faster and land slower. The concept seemed improved. Bolting a simpler bent-leaf-gear to the bottom of the fuselage was easier to design, package and build. Wings cantilevered from the fuselage required a center spar shortened to fuselage width. Repackaging 601HD and HDS from a more complex construct to a much simpler aircraft allows it to compete with all LSA. The same passenger, pilot, baggage and fuel are unchanged. The shorter center spar and longer wings refocused and magnified stresses within the fuselage across a much shorter and reduced section spar. It is this reduced spar section and length that increases material stress within the spar and fuselage attach points. Discussion seems focused on wings that fail and fold. I dont believe an XL wing has ever failed unless it was damaged externally. The center spar is, in design-terms, capable of doing its job when the aircraft is constructed correctly, not overloaded, and has properly torqued wing bolts. The safety margins in stress on the XL cannot be as forgiving as those found in the HD and HDS series because higher stresses are focused to a shorter lesser cross-section center-spar material. This newer canted angle spar design still meets the requirements and is thought to be statistically safe as demonstrated by a history of many older and actively flying XL. It is the margin of safety that needs to be addressed to preclude continuation of the problem, whether it is better builder-flyer adherence to loading, construction, etc or the introduction of a thicker section spar and better integration of spar connections with the fuselage. This kind of assumption would say that post-accident investigation would be unlikely to find anything that relates to cause until there are lots more broken parts and witnesses for comparing data. Early Bensen Gyrocopters went through a more frequent kind of the same pain until improvements were made much later when Bensens were no longer available. Even though a few Bensons are still flying, 601XLs are still way safer! Do fly safe guys, Larry McFarland 601HDS at www.macsmachine.com rans6andrew wrote: > > Juan, have you read the following, which I posted in December? Nobody has criticised it so I guess it is reasonable, level headed stuff. > > I had been thinking along the same lines as Scotsman (who is from South Africa, apparently) and then I came around to comparing accident types and rates with other Zenair(ith) designs. > > I don't know how many 601XLs there are out there or indeed how many 601HDs there are or 601ULs there are. In the UK we currently have 20 XLs on the register, 28 ULs , 17 HD and 10 HDS models. So less than 30 % of the fleet is XL types. > > Is this typical of the ratio in the world as a whole? > > If it is, assuming that the same sort of people buy/build ULs, HDs, HDSs and XL varients, assuming that the same spread of pilot abilities, the same ratio of aerobatic wannabees buy each model and the same spread of builder competences we should be hearing about 3 times as many in flight break ups of the non XL types as XL types. > > We don't. > > Where are the others? > > This line of thinking tells me that either I have missed something significant or that there is something peculiar to the XL. > Please correct me if there is a fatal flaw in my reasoning. > > Oh, and feel free to flame me 'cos it seems to be par for the course if you post from the UK! > > > Andrew - in the UK and building a 601UL. > I'm going to run the engine for the first time this weekend. > > -------- > A good way through building a 601UL with 912UL. > Still flying Rans S6 with 503. > > > ________________________________ Message 7 _____________________________________ Time: 01:06:49 PM PST US From: "Dave" Subject: Re: Zenith-List: Re: crash B.S. It's strange for an outsider to watch this three sided argument, on the one hand we have those (with money invested, not a neutral stance) who have absolute belief and faith in the XL. There IS not a problem and if the wings fell off in the driveway they would deny it. The opposing side who assumes there IS a problem and until it is proven that nothing can possibly ever go wrong will condemn the design. And the third (condemned by both preceding sides) who looks at what appears to be happening and wonders why that might be the case. Me? I have an idea and no expertise and no proof, so I wait and watch. I DO have an idea how this will play out that I am happy to share though. The XL will go down in history with a lot of other aircraft as a design that for some reason or other developed an undesirable history. Zenith will quietly retire the design and move on (CH-650). Those who have 601XL's will have either positive experiences and crow about the aircraft, others may have less positive experiences and will say nothing, but others will either blame or commiserate with them and post endlessly about it. For history ( and hysteria) look up the Beech (Doctor Killer) Bonanza or the Cirrus and there are others out there. Look folks, sometimes bad things happen, all designs should be endlessly suspect with an eye to making things better. ________________________________ Message 8 _____________________________________ Time: 01:52:02 PM PST US From: "Bill Naumuk" Subject: Zenith-List: Antennas All- Does anyone have any complaints with the stainless steel comm antennas from ACS? You know, the cheap ones? Having a hell of a time locating stuff I bought years ago and am just getting around to putting in. Also in dire need of a Narco -10 ELT antenna (God knows how I could lose something that big!) and a wiring harness for a King KT76TSO Transponder. TSO is actually part of the model number. Thanks. Bill do not archive Bill Naumuk Townville, Pa. HDS 601MG/Corvair 95% ________________________________ Message 9 _____________________________________ Time: 02:09:04 PM PST US From: "Peter W Johnson" Subject: Zenith-List: O-200 Electronic Tacho Hi Guys, How have you O-200 builders attached an electronic Tacho to the engine? Pickups on the P-Leads? Cheers Peter Wonthaggi Australia http://zodiac.cpc-world.com ________________________________ Message 10 ____________________________________ Time: 03:13:28 PM PST US Subject: Zenith-List: Re: O-200 Electronic Tacho From: "Sabrina" Off the P leads--make sure the equipment you are using is good quality and will not ground out your mags if it fails. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=233629#233629 ________________________________ Message 11 ____________________________________ Time: 04:17:53 PM PST US From: Lawrence Webber Subject: RE: Zenith-List: Antennas Bill dont feel bad i lost the fiberglass nose bowl i got from WW for 4 mo nths because i decided to clean up and put stuff where i wouldnt forget where i put them talk about senior moments Larry From: naumuk@windstream.net Subject: Zenith-List: Antennas All- Does anyone have any complaints with the stainless steel comm antennas from ACS? You know=2C the cheap ones? Having a hell of a time locating stuff I bought years ago and am just g etting around to putting in. Also in dire need of a Narco -10 ELT antenna ( God knows how I could lose something that big!) and a wiring harness for a King KT76TSO Transponder. TSO is actually part of the model number. Thanks. Bill do not archive Bill Naumuk Townville=2C Pa. HDS 601MG/Corvair 95% _________________________________________________________________ Windows Live=99 Contacts: Organize your contact list. http://windowslive.com/connect/post/marcusatmicrosoft.spaces.live.com-Blog- cns!503D1D86EBB2B53C!2285.entry?ocid=TXT_TAGLM_WL_UGC_Contacts_032009 ________________________________ Message 12 ____________________________________ Time: 08:36:52 PM PST US Subject: Zenith-List: Re: Lightning holes flange dies & sizes From: "Lee Steensland" At one point I posted about borrowing a set from someone. I planned to make a set of dies or have a set made, but the cheapest price I was quoted was like $500 or some such. I decided to just use a slotted stick with prices like that. If I could borrow a set that would be spectacular. 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