Fred,
Here is my two cents as an average builder:
Question 1
- Is Mod 73 a required mod for any aircraft based outside of the
UK?...particularly in the US?
My Comment:
The US declares you are the builder of the aircraft. You may modify or
choose not to modify your kit...It is your decision as the builder, as
the kit manufacturer is a 49% helper, but you are the builder. Just as
if you built the plane from scratch. It is highly recommended that all
ADs/mandatory actions directed by your kit manufacturer be followed. If
the UK's PFA or LAA grounds their planes, technically you don't have to
ground your experimental, but as some kit manufacturers have found, the
FAA can ground a kit if it believes losses are occurring due to design
problems or recommended/directed construction procedures... Your plane
is an experimental, each is technically different and the rules for FAA
involvement in monitoring the accidents, as in certified aircraft, does
not receive the same scrutiny... SLSA/ELSA have different rules like
certified aircraft.
Question 2
- If not, why implement Mod 73 when there is no evidence that a
problem with the original design exists?
My comment: This is a builder/maintainer issue. All builders are not
created equal nor is care always taken putting the tailplanes on and
off. Occasionally, the tailplanes are never taken off and rust on.
When taken off for inspections, so much force is used, the inner and or
outer bearing may be loosened and or broken loose and missed by the
owner. I have also seen that in their maintenance exuberance, owners
have sprayed oil into the stab holes and melted all the foam away from
the bearings leaving only glass to support the outer bearing. Believe
it or not some of the pip pin holes are so sloppy, pins can fall out and
other methods are used to secure the pin and tail plane...
If built and maintained properly, you may never have a problem, but the
Mod 73 tailplane mod, adds extra glass and support to ensure your outer
bearing is solidly glassed and in fact glassed more solidly. Down side
is you may need a longer pip pin. Oh well. Go to McMaster Carr.
Question 3
- Is Mod 73 an example of a prematurely arrived at "fix", approved and
implemented in a rush to get the Europa fleet airborne again before
the real culprit was determined...and...does it remain in effect today
out of a reluctance of regulatory agencies to set things right?
Comment:
Yes and no.
It is a quick and necessary bandaid to get the fleet flying abroad and
properly inspect the fleet.
I would prefer to see all of us to use the Europa Club mod of a tube of
glass supporting both bearings. This is a great mod, in my opinion, and
should be the standard. The NG control surfaces bond in the bearings
much more securely...Dare I say properly. But the bandaid of outer
bearing reinforcement is a great way of getting more support around the
bearing and checking the fleet.
The problem with the accident investigations is the cart and horse.
What caused Williams accident for sure? He had two problems, both
should have been caught and fixed during the build and through
subsequent inspections. The tail plane wobble is a point I harp on
constantly, that the stab should have no movement when attached. Yes, I
disagree with wallowing out the tube to allow the movement. Andy and I
have never seen eye to eye on this, but it doesn't hurt anything and
should flutter begin, the outer bearing is free to move a little. Dare
I say any flutter is BAD, and now you see why I disagree.
I have only found two flying aircraft with tailplane bearings broken
here at the shop. But I have done all the tailplanes IAW the mods,
because I believe it makes for a better product, and it is easy to sell
a plane with all the mods properly documented.
As an accident investigator in a prior life, we all die a little when we
loose a fellow aviator. It is our mission not to bury our loss by
saying it can't happen to me, but to try to make the aircraft,
procedures, or training better to save not just ourselves, but others
who come after us so they don't have to experience our loss.
Just my thoughts.
Bud Yerly
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