Members of the Planning Commission and Board of Zoning Appeals shall be resident voters of the City. The office of a member of the Planning Commission and the office of a member of the Board of Zoning Appeals shall become vacant upon his death, resignation, removal from office, or failure to attend three consecutive regular meetings without being excused by the Commission or by the Board, as the case may be, either before or after such failure of attendance. Upon such vacancy, Council shall, by majority vote, appoint a qualified successor to fill that vacancy.