Summary: A particular configuration of the LHD stellarator with an unusually flat pressure profile has been chosen to be a test case for comparison of the MHD stability property predictions of different three-dimensional and averaged codes for the purpose of code comparison and validation. In particular, two relatively localized instabilities, the fastest growing modes with toroidal mode numbers \(n=2\) and \(n=3\), were studied using several different codes, with the good agreement that has been found providing justification for the use of any of them for equilibria of the type considered.