53 Pa. Stat. § 16366
The judges of the supreme court, together with the judges of the district court and the court of common pleas of the city and county of Philadelphia, shall form a board of appointment, of which the chief justice of the supreme court shall ex officio be president, which shall convene in the city of Philadelphia, at such time and place as the said chief justice shall appoint, within eight weeks from the passage of this act, and select and appoint from the citizens of said city twelve persons to serve during good behavior as members of the before-mentioned board of directors of city trusts, subject, however, to removal as hereinafter provided; vacancies in the number of said directors of public trusts shall be filled from time to time by the said board of appointment; and any director of trusts may be removed from his office by the concurrent vote of two-thirds of the members of the board of appointment.
53 P.S. § 16366