Pa. Const. art. V, sched. § 11

(a) Except in the City of Philadelphia, section 10(d) of the article shall become effective upon the expiration of the term of the present president judge, or upon earlier vacancy. (b) Notwithstanding section 10(d) of the article the president judge of the Superior Court shall be the judge longest in continuous service on such court if such judge was a member of such court on the first Monday of January 1977. If no such judge exists or is willing to serve as president judge the president judge shall be selected as provided by this article. (Nov. 6, 1979, P.L.581, J.R.1)