William, all
>From what I understand right now, there are authorized and non-authorized >holes. Authorized holes are defined in the factory drawings. The one for the 415 series is available here. http://www.ercoupe.info/uploads/Main/drawings/a-544.jpg Two holes right in the center of the spar , each 4 holes holding frame C and the all the holes for the tanks and the walkway. Any other holes should be authorized per 337 or STC if there is such STC. The same is true for later models, where extra holes for seat and trim installations might have been added. Any other holes beyond that should be authorized to be legal. The request Mr. Caldwell was making was regarding the existence of some other unauthorized holes in the upper spar caps of the center spar. Due to our noise, it should be clear now even to the guys at Univair that there are spars out there that had modifications that included drilling holes. This alone is worth an AD, where any plane with unauthorized modifications to the main spar including holes will be grounded. Now to the authorized installations. If the holes drilled for such installations followed the pattern that the alons were using, they should pose no danger, but if holes were drilled through the spar caps extrusion more toward the edge I'd say it effects structural integrity and is a matter of concern. So what can we do? In our last AD that covered the center section, we made our voice heard and arranged that the center section can be checked with the wings of method or a boroscope. Mr. Caldwell suggests amending to this AD. We should give reasonable advice on how this amendment will look like. 1. First , no extra holes , no further action 2. Extra holes, documented - verify that it follows an approved pattern 3. Extra holes, not documented - certify if it follows the approved number and pattern 4. Extra holes not following an approved pattern or number. Replace spar cap or add stiffener provided by Univair ( has to be developed) Hartmut To: [email protected] From: [email protected] Date: Sat, 26 Sep 2009 23:12:54 -0500 Subject: [ercoupe-tech] Re: ACS 8/14/09 - In-flight Breakup of Ercoupe 415-D, NTSB ERA09FA087 All, Following up on my post of 9/24/09 at 16:06: 1. The holes: I believe the "Unauthorized" holes of concern to be pretty much as those described in my FAA comments thusly: "Per production drawing F53180 (Rev. B dated 6/10/60), the Forney F-1A bucket seats are secured at the front by one left and right hook mounts of similar construction. Centerlines of these hooks are 4.437" outboard of the aircraft centerline and then 10" further outboard on each side. Each such hook is mounted to the main spar by four 8-32 fasteners. Installation required a total of sixteen 11/65" (.171) holes to be drilled through the spar cap. These are drilled in pairs, aligned fore and aft, at eight locations. Per production drawing F53189 L/R (Rev. A dated 2/4/60) the fore-aft separation is .875". Per production drawing F53190 L/R (Rev. A dated 2/4/60) the port-starboard separation is 1.468". Holes drilled in the main spar for the forward attachment of bucket seats installed in later production Forney, Alon and M10 (TCDS 787) airframes may or may not be identical in number, size and location between manufacturers. Please research and advise as to any variations, considering this request my IR#17. The production change to bucket seats received appropriate FAA review, was timely approved almost fifty years ago, and has proven safe in extended service, and has been approved as a retrofit in earlier airframes by approved 337. Accordingly, there should be a strong presumption that any associated reduction in spar strength resulting from the drilling or presence of such holes is of no overall structural significance." 2. Univair: Per Mike Wotovitch, Univair has been in contact with the FAA Denver Aircraft Certification Office regarding this ACS. Comments were submitted about a week and a half ago, and they have requested a "sit-down meeting" before the comment period on this ACS expires on October 7th. I understand that they generally agree that the FAA is presently pursuing an unproductive course as to the likely cause of the Sebring crash and an effective response, and they do take this ACS seriously. 3. EOC: I have heard indirectly that John Wright, Sr., A&P, IA and EOC Technical Representative, has been working with Univair for some time on the issue; and is of the opinion that excess aileron play was the cause. Skip and I have talked at some length and he is personally preparing a response. On Friday I mailed him photocopies of my (revised) personal comments to the FAA and full text copies of documents I referenced therein. I emailed an information package to Marv. Dunlap, who has been working with the FAA for years to get the ERCO Four into the air, and also to several Tech members who have unique and prestigious qualifications for further in-depth evaluation of this ACS, etc. My (revised) personal comments went out Friday to the FAA via U.S.P.S. Certified Mail, Return Receipt Requested with full text copies of documents referenced therein. Regards, WRB -- On Sep 22, 2009, at 13:53, Mike Willis wrote: Does anyone know the answers to these questions please? 1 Do we know yet which holes are of concern? 2 What actions and response are Univair preparing? 3 What actions and response are Skip and the EOC preparing? I’m assuming the FAA will take more note of 2 and 3 than individuals. Thanks, Mike _________________________________________________________________ More than messages–check out the rest of the Windows Live™. http://www.microsoft.com/windows/windowslive/
