TCDS
here for those interested. Can't immediately see which model you are looking at but the comments are generic.
The CG limits are 85 to 93 inches, and starting from 2400lbs up to 2900lbs, the forward limit gets closer to the aft limit, with MTOW having 89 to 93 in of buffer.
Not too sure what you mean by "buffer" but let's not get bogged down with that one.
The aircraft in question has a BOW of 1808lbs since its last weight and cg determination, and the CG was at 79.96 inches. I found it strange .. but the cg is off the charts!
Empty CG entirely dependent on build and configuration. Generally see forward-ish CG for light 4 place singles otherwise the loaded case can get a tad aft-ish.
We are not all that concerned with the empty CG .. rather the ZFW, TOW CG and what the fuel burn might be doing in between.
I redid several times with different calculations ... Everytime the CG is off limits, too forward.
This suggests one of
(a) the empty weight data is wrong
(b) the configuration is inappropriate and either the aircraft needs to be reconfigured or ballasted to remove the problem
(c) your sums are wrong
a culture where people disregard doing W&B for small aircraft
you MUST do whatever is appropriate to determine that the flight is inside the envelope. This doesn't necessarily mean you have to do a calculation every flight but you must be able to satisfy yourself (and demonstrate to the Regulators, Insurers, etc) that you are inside the envelope throughout the flight
a few inches off the envelope doesn't do harm
might not do any harm other than killing you and your passengers ....
is it 3 or 4 inches forward of the cg limit (if the forward limit is 85 inches, I'm talking here 81, 82 inches) not to worry about?
I do hope that you are not serious with this question.
From the regulatory/legal/insurance viewpoint, you have a problem as soon as you are forward/aft of the relevant limit.
From a more practical concern, the limits represent compliance with the Certification Design Standards. It follows that, as you move outside the limits, the Standards are being compromised in one or more respects. Progressively you eat into the margins until you kill yourself .. pretty simple.
People constantly tell me that the roundout to touchdown the aircraft has a heavier nose and it's hard to pull, to trim up, etc. But that does seem normal with some aircraft.
Increased stall speed - what margins are you carrying ?
Increased structure loads on the tail and nose wheel. Does that worry you at all ?
Increased stick loads associated with increased long static stability. Do the handling implications bother you at all ?
Should I worry about this or not?
.. and then some.
If a CG more forward than the certificated limit is acceptable
that's the basic problem .. it's NOT acceptable.
and the aircraft has been flying for a long time without any incident,
your luck might be about to change ...
how does one measure the actual true value of the CG limits of light aircraft's AFM/POH?
one does that by referring to the information in the weight and balance section of the POH. The aerodynamicists have done the sums and come up with the figures. The TPs have gone out and verified/amended those figures .. and the end result is published in TCDS and POH. There is NOTHING left for the pilot to measure .. just a matter of complying with the rules.
How do you convince the pilots and operatores of this small aircraft to respect the manual and the W&B procedures, when they always operate out of the envelope and nothing dangerous ever happens?
The owner should be worried about his insurance when he ends up with the bill after the accident .. whenever it might happen .. as it eventually will almost certainly do.