L13 Blanik Mandatory Bulletin

Inspection was done on our Blahnik this afternoon....

Our Blahnik has a low number of flight...ie. only 1200 hours with 1750
starts.
No acrobatics flight except a few rare loopings...

Always aerotowed...No winch launches...

Inspection with eyes and bright light showed nothing. We took pictures
wtih a small digital cam equipped with a flash (small Olympus one).

When we uploaded the pictures on the PC, we carefully looked at the
pictures and we saw ...longs thin cracks...
With the eyes it was impossible to detect due to the fact that the
available room for inspection is very limited....

We spoke in the previous post about fatigue....well, I am deeply
convinced that our Blahnik has never been "fatigued"....
The cracks seems to be produced because the rivet from which the
cracks are born, has been installed by a hand process during the
manufacturing. The manual process for installing these rivets is clear
on the picture I took.
I strongly suspect a poorly manual manufacturing process instead of a
fatigue problem.

I am really upset to discover this problem now especially that there
is no repair procedure nor a replacement procedure.

The AD just states that the Blanik is grounded. This is unacceptable

On Jun 25, 8:41*am, nimbus wrote:

When we uploaded the pictures on the PC, we carefully looked at the
pictures and we saw ...longs thin cracks...

I would be really skeptical about things that show up in a digital
photo that don't appear under direct observation. It could be that
what looks like cracks are artifacts of the digital photography or
JPEG compression. I would recommend you get a second opinion before
taking any action.

Also, it could be that what looks like cracks are actually just normal
striations from the extrusion process by which the spar caps are
formed. They could also be local disruptions in the surface anodizing,
if the parts are anodized. We've seen that around rivets on the
anodized spars of RV-series homebuilt airplanes, and it has not been a
structural concern.

Thanks, Bob K.

On Jun 25, 11:41*am, nimbus wrote:
Inspection was done on our Blahnik this afternoon....

Our Blahnik has a low number of flight...ie. only 1200 hours with 1750
starts.
No acrobatics flight except a few rare loopings...

Always aerotowed...No winch launches...

Inspection with eyes and bright light showed nothing. We took pictures
wtih a small digital cam equipped with a flash (small Olympus one).

When we uploaded the pictures on the PC, we carefully looked at the
pictures and we saw ...longs thin cracks...
With the eyes it was impossible to detect due to the fact that the
available room for inspection is very limited....

We spoke in the previous post about fatigue....well, I am deeply
convinced that our Blahnik has never been "fatigued"....
The cracks seems to be produced because the rivet from which the
cracks are born, has been installed by a hand process during the
manufacturing. The manual process for installing these rivets is clear
on the picture I took.
I strongly suspect a poorly manual manufacturing process instead of a
fatigue problem.

I am really upset to discover this problem now especially that there
is no repair procedure nor a replacement procedure.

The AD just states that the Blanik is grounded. This is unacceptable

Would you consider posting those pics somewhere?

- Evan Ludeman / T8