303.58  Powers of board.
  The board of adjustment may:
  1.  Hear and decide appeals where it is alleged there is error in an order, requirement, decision, or determination made by an administrative official in the enforcement of this subchapter or of any ordinance adopted pursuant to it.
  2.  Hear and decide special exceptions to the terms of the ordinance upon which the board is required to pass under the ordinance.
  3.  Authorize upon appeal, in specific cases, a variance from the terms of the land use plan which are not contrary to the public interest, where owing to special conditions a literal enforcement of the plan would result in unnecessary hardship, and so that the spirit of the plan shall be observed and substantial justice done.
83 Acts, ch 108, §18