53 Pa. Stat. § 14103
Whenever any such city of the first class shall hereafter enter upon, take, use, and appropriate private property for the aforesaid purposes by ordinance or resolution, and the compensation and damages arising therefrom cannot be agreed upon by the owners thereof and such city, any court of common pleas or any judge thereof in vacation on application thereto by petition by the city or any person interested shall either before or after the entering, taking, using, or appropriating of such private property appoint three viewers from the board of viewers of the county, and appoint a time, not less than twenty nor more than thirty days thereafter, when the viewers shall meet upon the property entered, taken, used, or appropriated, and view the same.
The viewers shall give at least ten days' notice of the time of their first meeting by publication in one or more newspapers of the city and by handbills posted upon the premises or otherwise, as the court shall direct. The viewers having been sworn or affirmed faithfully, justly, and impartially to decide and a true report to make concerning all matters to be submitted to them and in relation to which they are authorized to inquire, and having viewed and examined the property shall hear all parties interested and their witnesses, and shall determine the damages or benefits for property entered, taken, used, or appropriated and to or by whom the same are payable, and having determined the same they shall prepare a schedule thereof and report the same to the court and file therewith a plan showing the property entered, taken, injured, benefited or destroyed.
53 P.S. § 14103