On Jun 23, 6:58*am, John Smith wrote:
Am 23.06.10 04:23, schrieb BT:

Reading the MB, It appears that based on the "flight data" of the
aircraft, and high number of launches per flight hour, the concern is
overstressing from repeated winch launches. LET is requesting all users

Sigh. The urban legend lives.

Can you please clarify that remark? I don't see any urban legendry
here.

Winch launching inherently load the wings in bending more than
aerotow. Maybe not enough to actually exceed the design load of the
wings. But certainly enough to contribute a substantial amount of
fatigue and to make a measurable difference in long-term service
life.

When fatigue has weakened a structure, and then you apply a load that
exceeds the diminished capacity of that structure, it will fail. You
can say that it was overstressed, or you can say that it wasn't
overstressed and that it just exhibited a fatigue failure. Whatever
you call it, you still have a broken structure.

Thanks, Bob K.