---------------------------------------------------------- Yak-List Digest Archive --- Total Messages Posted Thu 01/26/12: 7 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:41 AM - Re: Tailplane front spar crack (Etienne Verhellen) 2. 12:42 AM - Re: Tailplane spar... (Etienne Verhellen) 3. 10:34 AM - Re: Re:Tailplane front spar crack (Brian Lloyd) 4. 10:38 AM - Re: Re:Tailplane front spar crack (Brian Lloyd) 5. 10:56 AM - Re: Tailplane front spar crack (Elmar & Manuela Hegenauer) 6. 03:16 PM - Re: Tailplane AD (Jay McIntyre) 7. 05:30 PM - Re: Re:Tailplane front spar crack (Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E) ________________________________ Message 1 _____________________________________ Time: 12:41:03 AM PST US Subject: Yak-List: Re: Tailplane front spar crack From: "Etienne Verhellen" Here is the UK CAA version : http://www.caa.co.uk/docs/33/20111216MPD2011010.pdf Read this topic online here: http://forums.matronics.com/viewtopic.php?p=364864#364864 ________________________________ Message 2 _____________________________________ Time: 12:42:13 AM PST US Subject: Yak-List: Re: Tailplane spar... From: "Etienne Verhellen" Here is the UK CAA version (Mandatory Permit Directive) : http://www.caa.co.uk/docs/33/20111216MPD2011010.pdf -------- http://www.flyforfun.be/?q=yaks http://www.planecheck.com/eu/index.asp?ent=dv&id=6711 http://www.airshowactionphotography.com/san07/page1.html http://www.irishairpics.com/photo/1029467/L/Yakovlev-Yak-52/G-CBSS/Etienne-Verhellen/ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=364865#364865 ________________________________ Message 3 _____________________________________ Time: 10:34:30 AM PST US Subject: Re: Yak-List: Re:Tailplane front spar crack From: Brian Lloyd On Tue, Jan 24, 2012 at 8:06 PM, doug sapp wrote: > Craig, > I think we may have had this discussion before, I can't recall for sure, but > you are correct in that an fix was engineered, but rather it was actually > "accepted by the FAA" is up for debate and really does not matter. It is in > my opinion a very poor fix indeed, it simply makes the center of the spar so > stiff that it cannot flex, the result is that iteffectively shifts the > stress the the edges of thedoubleras you have correctly stated. Yes, you are right Doug. We had this discussion on here when the list was first started. I remember suggesting that the doubler transfers the stresses to the spar at the end of doubler, just moving the problem rather than solving it. I suggested a tapered or laminated doubler so that the stresses are transferred gradually from the doubler to the spar along the length of the doubler. OTOH, since no one seems to be seeing new cracking at what appears to be the new stress point at the end of the doubler, we have solid empirical evidence that there isn't a problem with the current doubler design. So even if it appears to be a poor design, the evidence suggests that it is working OK. At this point I think I am going to come down on the side of, "if it ain't broke, don't fix it." -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 brian@lloyd.com +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) ________________________________ Message 4 _____________________________________ Time: 10:38:16 AM PST US Subject: Re: Yak-List: Re:Tailplane front spar crack From: Brian Lloyd On Wed, Jan 25, 2012 at 12:32 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote: MALS-14 64E" > > Based on Dougs less than positive support for this fix, it would seem that a wise thing to do would be to see the actual recommendations made by the FAA Designated Engineering Representative (DER) regarding the repair of this specific crack. Well, as I suggested in my last email, we don't seem to be seeing any cracking of the spars that have this mod, even if it appears that the mod may not be the best design possible. The doubler appears to be working just fine. I would counsel that people just keep monitoring those aircraft that have the mod to see if it ever becomes a problem. I would *not* counsel inventing problems and raising red flags with the FAA if there is no immediate evidence of a problem, and there appears to be no evidence at this point in time. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 brian@lloyd.com +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) ________________________________ Message 5 _____________________________________ Time: 10:56:01 AM PST US From: Elmar & Manuela Hegenauer Subject: Yak-List: Re: Tailplane front spar crack Please see attached picture. cheers Elmar ________________________________ Message 6 _____________________________________ Time: 03:16:05 PM PST US Subject: Yak-List: Re: Tailplane AD From: Jay McIntyre Hmmm... that is interesting. Try http://www.caa.govt.nz/Airworthiness_Directives/Airworthiness_Directives_Ae roplane.htm and then scroll through the list until you get to "CJ-6 series" Cheers, Jay On Fri, Jan 27, 2012 at 9:52 AM, Jerry Painter wrot e: > *Hi Jay--* > ** > *Can't get your AD link* > > *http://www.caa.govt.nz/Airworthiness_Directives/CJ6.pdf* > > * to open--right URL?* > ** > =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF =BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB =EF=BB > *Jerry Painter* > ** > ** *Wild Blue Aviation* > *425-876-0865* > *FlyWBA@gmail.com* > *www.FlyWBA.com* > > *Flight Training* > *Aircraft Restoration and Maintenance * > *Pilot Supplies* > > *Hangar 28* > *Arlington Municipal Airport* > *18228 59th Dr. NE* > *Arlington, WA 98223* > [image: FREE Animations for your email - by IncrediMail! Click Here!] > ________________________________ Message 7 _____________________________________ Time: 05:30:37 PM PST US Subject: RE: Yak-List: Re:Tailplane front spar crack From: "Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E" I don't own a CJ-6, so I really have no dog in this fight. Whatever you all think is best is just peaches with me. Mark ________________________________ From: owner-yak-list-server@matronics.com on behalf of Brian Lloyd Sent: Thu 1/26/2012 1:35 PM Subject: Re: Yak-List: Re:Tailplane front spar crack On Wed, Jan 25, 2012 at 12:32 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote: > > Based on Dougs less than positive support for this fix, it would seem that a wise thing to do would be to see the actual recommendations made by the FAA Designated Engineering Representative (DER) regarding the repair of this specific crack. Well, as I suggested in my last email, we don't seem to be seeing any cracking of the spars that have this mod, even if it appears that the mod may not be the best design possible. The doubler appears to be working just fine. I would counsel that people just keep monitoring those aircraft that have the mod to see if it ever becomes a problem. I would not counsel inventing problems and raising red flags with the FAA if there is no immediate evidence of a problem, and there appears to be no evidence at this point in time. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 brian@lloyd.com +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message yak-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Yak-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/yak-list Browse Digests http://www.matronics.com/digest/yak-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.