Easy. As a new 'coupe owner, I'm not willing to take the chance of my airplane being grounded for a couple years while the FAA and Univair figure out an expensive solution. I plan to install a new center section with a factory-standard two-hole main spar cap. Yes, I know it's a radical solution and will be expensive, but the people telling me to hold off don't have 12 additional holes drilled into their main spar cap and a daughter who wants to fly. It's a huge investment, but nobody can predict what it's going to cost to remedy the problem later vs. doing it now. So I'm willing to donate my main spar to the FAA or EOC to perform destructive testing if that's what it takes. Someone needs to find out where the failure point is. That's the good news. The bad news is that I won't have it out until sometime in November. We need to slow this train down long enough to get the data we need.
--- In [email protected], Caliendo Dan <djcalie...@...> wrote: > > So how do we "prove" this to the FAA. I wonder if we need to hire a > DER which I understand the FAA listens to? > I don't propose doing this until we are in the comment period of an > actual AD; but maybe we need to be ready > for it. I see very little emphasis placed on the overloading of the > wings by "manuevers". If you stress any plane > beyond it's limits it is going to fail someplace (most likely the > wings or aileron). > > Dan Caliendo > Ercoupe Mach 0.14 > 3658H > > On Sep 27, 2009, at 9:19 AM, bigbrownpi...@... wrote: > > > Ed, > > > > You presume that the FAA requires a higher burden-of-proof than > > suspicion that the holes contributed to an inflight breakup. They > > will probably take the most conservative course in the name of > > "acting in the public interest". They don't have to show anything. > > WE do. Without current data to show the FAA that our main spars are > > not subject to increased structural fatigue due to additional holes > > is the main spar cap, I'm afraid all these arguments are moot. They > > can brush off any 337's they approved, the certification of the > > Forney and Alon main spar, and even the Fred Weick letter simply by > > stating that "new information has come to light concerning > > cumulative fatigue in modified main spars as a result of the > > Sebring mishap". It's done all the time-- part of the reason UPS > > parked our re-engined and modernized 727-100 QF's rather than > > comply with the AD's the FAA required under the Aging Aircraft > > Program. > > > > We need data, not arguments. Unfortunately, I'm afraid the burden > > of proof is going to fall on us to prove to the FAA that our > > aircraft are safe. It may not be fair, but it is what it is > > > > Dave > > > > --- In [email protected], "Ed Burkhead" <ed@> wrote: > > > > > > > > > > > > > > > > > > Hartmut suggests these possibilities for holes found in the > > center section > > > spar: > > > > > > > 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) > > > > > > > > > > > > At the least, I would suggest a second remedy to option 4: > > Provide an > > > engineering analysis by a DER or other qualified individual > > showing the > > > extra holes do not degrade the spar strength beyond required limits. > > > > > > > > > > > > For example, the designer's letter: > > > > > > http://edburkhead.com/Ercoupe/fred_weick_reply_on_holes.htm > > > > > > > > > > > > And, indeed, before an AD is issued or amended, the FAA should > > show that > > > spar holes degrade the strength beyond acceptable limits. So far, > > we have > > > only a single instance in which a spar failed, very possibly due > > to extreme > > > loads due to aileron flutter and/or a sudden high-g pull-up, > > possibly at > > > higher than normal airspeed. I question that this instance justifies > > > grounding aircraft due to the spar holes. > > > > > > > > > > > > As always, aircraft which have controls that don't meet the > > specifications > > > in ERCO Service Department Memorandums 56 and 57 are unairworthy. > > > > > > > > > > > > Ed > > > > > > > >
