Michael wrote:
Can an
average GA plane take off with a load great enough to cause damage in
the event of hitting some chop? I don't know, but I suspect that should
be the least of one's worries.

That depends on the airplane. If you're dealing with a normal category
airplane with old and possibly deteriorated wing structure, I sure
would worry about it. Some of the heavier Cessna twins that served a
lifetime in hauling cargo (where, contrary to regulations, gross weight
is often exceeded, as is zero fuel weight on short runs). Consider
these accidents:

Point taken. I guess I would lump this in with the T-34 accidents we've
seen which IIRC have involved exclusively planes used in weekend
fighter pilot games.

In your opinion, if you have a structure which has been fatigued beyond
book limits over many years (find a 402 that hasn't?), how do you judge
what's safe?

CG seems a more pernicious issue to me, as the plane's behavior can
fool you. Chances are you won't realize you're thoroughly screwed until
after you're up in the air without any good options.

Well, that's overstating the case by quite a lot. The cg needs to be
quite a bit aft of limits before normal flight and a normal landing are
a problem. Oh, you'll feel the reduced longitudinal stability, but it
likely won't be bad enough to keep you from landing the plane. Just
don't stall.

That was kind of my point. Seems like a departure stall is how a good
number of these flights end.

In addition to
takeoff CG, I'd also compute CG with half fuel and very little fuel,
just in case.

It's not a just in case. In the Beech Bonanza, it's a real issue. As
you burn fuel, cg moves aft - and unless you have some real big boys up
front and little or nothing in back, you're never far from the aft
limit anyway. On the other hand, you have to try real hard to get a
Brand C or Brand P aft of limits.

As I exceed FAA standard dimensions considerably myself, I've never
lost too much sleep on this point

-cwk.