Section R. 259.304 - Supervision of running enginesRule 304.
(1) An aircraft engine shall not be started unless a competent operator is in the aircraft attending the engine controls.(2) Blocks equipped with ropes or other suitable means of removing the blocks shall always be placed in front of the wheels before starting the engine, unless the aircraft is equipped with adequate parking brakes and the brakes are effectively set.(3) An aircraft shall be started and warmed up only in areas designated for such purposes.Mich. Admin. Code R. 259.304