Capt.Doug wrote:
"William W. Plummer" wrote in message Is it the tail or the wings that

get snapped off. Hauling back on the

yoke loads up the elevator. The wings are near the center of gravity so
they don't get stressed as much.


It depends on the structure. The T-28 Trojan was used by the South
Vietnamese in their conflict for ground attack roles. The pilots were
pulling the wings off much too often and the engineers couldn't understand
because those wings should support a battleship. It turns out that the
horizontal stabilizer was actually the first component to fail. After it
failed, the plane would pitch over with enough force to break the wings off.
This happens in less than a second. Once the engineers understood the
problem and strenghtened the horizontal stabilizer, the problem went away.

Other planes break apart in different ways. The T-34 has been in the news
quite a bit lately because of wings falling off. It appears that the tail
isn't breaking. The cause is attributed to metal fatigue from repeated large
stresses. A C-130 water bomber was videotaped as the wings came off. The
cause has been determined to be undetected cracks in the bottom wing skins
that were hidden by doublers. An airworthiness directive was recently aimed
at the Cessna 400 series because of a wing seperation. It turns out that the
causal factors of the seperation were damage during building by the
manufacturer and repeated overstressing during years of abuse in Alaska.

D.


Metal fatigue, cracks and construction defects are not caused by
turbulence although turbulence may be the straw that breaks the camel's
back when those problems exist.

IIRC the Convair Electra was the first plane that metal fatigue was
determined to be the cause of its wings coming off. And, it took
years. What caused the fatigue? Gyroscopic motion of the wings.