Actually, I don't believe flying at max gross is necessarily safe
either.

If you have ever flown slightly gross weight, then you have already
flown as a test pilot. First, the official weight and balance is
probably decades old, and your aircraft most likely weighs several
pounds more now. Second, people under-estimate their weight. Unless you
have a weighing scale as people board, you can never be sure of the
actual weight. Finally, the aircraft is far different from when it was
tested during manufacture. A dirty airframe will reduce performance,
and an old prop will not work as well as a brand new one. Most
importantly, your engine definitely will not perform like a brand new
engine. So, whether you like it or not, you have already been a test
pilot. For this reason, I never fly an aircraft near its max gross. I
have seen pilots diligently trying to unload weight until it is exactly
equal to the max gross weight.







"Peter Duniho" wrote in
:

"Mike Granby" wrote in message
oups.com...

"once you go over the max weight,
you are essentially a test pilot".

That's putting it a bit strongly.

No, it's putting it quite accurately.

As long as the CG issues are OK, the
effects of being reasonably over-weight are quite predictable in
terms of stall speed, take-off requirements etc.

The effects of flight at any weight are quite predictable in terms of
stall speed, take-off requirements etc. And yet, during
certification, the airplane is required to be *tested* at in a variety
of configurations by a *test pilot* to demonstrate the actual
performance.

Just because one can predict the performance, that doesn't change the
fact that a person flying an airplane in an untested (as far as they
know) configuration is a "test pilot".

The structural issues won't
come into it as many aircraft have their max gross determined by
other things (eg. stall speed low enough for Part 23, or the need to
go-around at max gross with full flaps)

Very few single-engined airplanes have a stall speed at the maximum
allowed value (noting, of course, that the "maximum allowed value"
isn't really so much a hard limit, but rather one that a manufacturer
is required to meet in order to avoid other things). It's true that
max gross weight may be affected by things other than structural
issues, but there is no way to know whether this is true without
consulting the manufacturer (which I doubt the theoretical over-gross
pilot is going to do), and I can think of at least one common airplane
for which structural issues DO limit the maximum landing weight (which
is lower than the maximum takeoff weight for that airplane).

and in any case, there's a
large safety margin in there.

The reason for that safety margin is for normal, legal weight
operations. It's not so you can operate over the legal limits.
Operate over the legal weight, and you've just abandoned your "large
safety margin".

The fact is that assuming you're not on
the edge re DA or runway length, 5% overweight is going to be safe.
It isn't legal, but it will be safe.

It *might* be safe. You are still a test pilot when flying over the
legal weight, which is the comment to which you replied.

As to the arguement that breaking one
rule leads to breaking another, with respect, that is nonsense.
That's like saying speeding leads to murder...

That's a matter of opinion, I guess. I personally believe that if we
had better enforcement of the little laws, we wouldn't have so many
people disregarding the more important ones. Looking the other way
when it comes to speeding (and similar) simply teaches people
disregard for rules. Each person winds up setting their own limits,
rather than respecting the limits society claims to have made. And
yes, in some cases, those limits go way beyond just speeding.

Obviously each individual who speeds doesn't wind up a murderer, but
general disregard for the rules does certainly lead to other negative
behavior.

Pete