Lomcevak
A national regulatory authority can apply any standards seen as reasonable and justifiable irrespective of the country of origin certification basis.
Compliance with an airworthiness certification standard does not automatically guarantee the product is truly fit to fly eg DH Comet.
Anyway, that is not my reading of the OP's comment re FAR Part 23.
It could be the Australian ATSB recommends an artificial stall warning be fitted.
FAR Part 23.203 requires accelerated stall tests at up to 5kts per second deceleration rate. Clearly at 75% power and 30 degrees of bank, light weight, considerable G will be applied for these test. These same test can result in almost aerobatic attitudes with extremely low airspeeds.
Also, 1 turn spin test are required of all (FAR23) single engine aircraft - by implication this gives test pilots further opportunity to assess stall characteristics.
I am not sure why changes in longitudinal and directional static stability would affect stall speeds. In any case, any stability deficiencies are normally addressed by aerodynamic add-ons and revised CG limits.
There are differences in the various Beaver manuals available on-line. The anomaly you noted is not present in all the manuals that I viewed. Similarly, at least one manual showed stall speeds for, land plane, ski plane, and float plane - there being no differences in speeds according to that manual.
Simple theory for stall speeds under various g loadings may not give you the expected results if you don't know the airspeed pressure error correction under G.
Last edited by zzuf; 6th Jan 2018 at 13:37.