"Brad Zeigler" wrote in message

"Yeah, its a limitation." He reasoned as he showed me the POH W&B graph.
The line to calculate moment stops at 400lbs.
I've never heard this before. Has anyone else? Otherwise, I've broken
the rules on nearly every flight with a passenger or student more than
140lbs

Yes, we had to live with this when I was instructing in the seventies. As
explained to me, the source limitation is the structural capacity of the
floor structure when subjected to max certificated g loading. But you are
right in that it is mentioned nowhere in the text of the limitations
section.