An inertial sensor comprising: a proof mass structure (22, 92) spaced apart from a planar surface (28, 94) of a substrate (30, 96), said proof mass structure (22, 92) having a first section (40, 106) and a second section (42, 108), said first section (40, 106) having a first mass that is greater than a second mass of said second section (42, 108); an anchor (24, 98, 100) coupled to said planar surface (28, 94) of said substrate (30, 96); and a spring system (26, 102, 104) interconnected between said anchor (24, 98, 100) and said first and second sections (40, 42, 106, 108) of said proof mass structure (22, 92), said spring system (26, 102, 104) being configured to enable translational motion of said first and second sections (40, 42, 106, 108) of said proof mass structure (22, 92) in response to linear acceleration forces (64, 72, 78) imposed on said inertial sensor (20, 90, 152) in any of three orthogonal directions (58, 60, 62), characterized in that said spring system (26, 102, 104) comprises: a first spring element (44, 120); a rotational beam (46, 122) having a first beam end (52, 128) and a second beam end (54, 130), said first spring element (44, 120) interconnecting said anchor (24, 98, 100) and a midpoint (56, 132, 134) of said rotational beam (46, 122), said midpoint (56, 132, 134) being centered between said first and second beam ends (52, 54, 128, 130); a second spring element (48, 124) interconnecting said first beam end (52, 128) of said rotational beam (46, 122) and said first section (40, 106) of said proof mass structure (22, 92); and a third spring element (50, 126) interconnecting said second beam end (54, 130) of said rotational beam (46, 122) and said second section (42, 108) said proof mass structure (22, 92). a proof mass structure (22, 92) spaced apart from a planar surface (28, 94) of a substrate (30, 96), said proof mass structure (22, 92) having a first section (40, 106) and a second section (42, 108), said first section (40, 106) having a first mass that is greater than a second mass of said second section (42, 108); an anchor (24, 98, 100) coupled to said planar surface (28, 94) of said substrate (30, 96); and a spring system (26, 102, 104) interconnected between said anchor (24, 98, 100) and said first and second sections (40, 42, 106, 108) of said proof mass structure (22, 92), said spring system (26, 102, 104) being configured to enable translational motion of said first and second sections (40, 42, 106, 108) of said proof mass structure (22, 92) in response to linear acceleration forces (64, 72, 78) imposed on said inertial sensor (20, 90, 152) in any of three orthogonal directions (58, 60, 62), characterized in that said spring system (26, 102, 104) comprises: a first spring element (44, 120); a rotational beam (46, 122) having a first beam end (52, 128) and a second beam end (54, 130), said first spring element (44, 120) interconnecting said anchor (24, 98, 100) and a midpoint (56, 132, 134) of said rotational beam (46, 122), said midpoint (56, 132, 134) being centered between said first and second beam ends (52, 54, 128, 130); a second spring element (48, 124) interconnecting said first beam end (52, 128) of said rotational beam (46, 122) and said first section (40, 106) of said proof mass structure (22, 92); and a third spring element (50, 126) interconnecting said second beam end (54, 130) of said rotational beam (46, 122) and said second section (42, 108) said proof mass structure (22, 92). a first spring element (44, 120); a rotational beam (46, 122) having a first beam end (52, 128) and a second beam end (54, 130), said first spring element (44, 120) interconnecting said anchor (24, 98, 100) and a midpoint (56, 132, 134) of said rotational beam (46, 122), said midpoint (56, 132, 134) being centered between said first and second beam ends (52, 54, 128, 130); a second spring element (48, 124) interconnecting said first beam end (52, 128) of said rotational beam (46, 122) and said first section (40, 106) of said proof mass structure (22, 92); and a third spring element (50, 126) interconnecting said second beam end (54, 130) of said rotational beam (46, 122) and said second section (42, 108) said proof mass structure (22, 92).