53 Pa. C.S. § 1135
This section is applicable to officers of municipalities not included in section 1134 (relating to enabling authority for emergency interim successors for local offices). Each officer, subject to any regulations as the executive head of the municipality may issue, shall designate by title, if feasible, or by named person, emergency interim successors and specify their order of succession. The officer shall review and revise, as necessary, designations made pursuant to this subchapter. The officer will designate a sufficient number of persons so that there will be not less than three deputies or emergency interim successors, or any combination of them. If any officer or deputy of any municipality is unavailable, the powers of the office shall be exercised and the duties discharged by his designated emergency interim successors in the order specified. The emergency interim successors, in the order specified, shall exercise the powers and discharge the duties of the office to which designated until the vacancy is filled in accordance with the Constitution of Pennsylvania or statutes or until the officer, or his deputy or a preceding emergency interim successor, ceases to be unavailable.
53 Pa.C.S. § 1135