(a) The Tribunal shall be composed of five commissioners appointed by the President with the advise and consent of the Senate for a term of seven years each; of the first five members appointed, three shall be designated to serve for seven years from the date of the notice specified in section 801(C), and two shall be designated to serve for five years from such date, respectively. Commissioners shall be compensated at the highest rate now or hereafter prescribe sic for grade 18 of the General Schedule pay rates (5 U.S.C. 5332). (b) Upon convening the commissioners shall elect a chairman from among the commissioners appointed for a full seven-year term. Such chairman shall serve for a term of one year. Thereafter, the most senior commissioner who has not previously served as chairman shall serve as chairman for a period of one year, except that, if all commissioners have served a full term as chairman, the most senior commissioner who has served the least number of terms as chairman shall be designated as chairman. (c) Any vacancy in the Tribunal shall not affect its powers and shall be filed, for the unexpired term of the appointment, in the same manner as the original appointment was made. Section 803. Procedures of the Tribunal. (a) The Tribunal shall adopt regulations, not inconsistent with law, governing procedure and methods of operation. Except as otherwise provided in this chapter, the Tribunal shall be subject to the provisions of the Administrative Procedure Act of June 11, 1946, as amended (c. 324, 60 Stat. 237, title 5, United States Code, chapter 5, subchapter II and chapter 7). Section 804. Institution and conclusion of proceedings. (a) With respect to proceedings under section 801(b)(1) concerning the investment of royalty rates as provided in sections 115 and 116, and with respect to proceedings under section 801(b)(2)(A) and (D)-- (1) on January 1, 1980, the Chairman of the Tribunal shall cause to be published in the Federal Register notice of commencement of proceedings under this chapter; and (2) during the calendar years specified in the following schedule, any owner or user of a copyrighted work whose royalty rates are specified by this title, or by a rate established by the Tribunal, may file a petition with the Tribunal declaring that the petitioner requests an adjustment of the rate. The Tribunal shall make a determination as to whether the applicant has a significant interest in the royalty rate in which an adjustment is requested. If the Tribunal determines that the petitioner has a significant interest, the Chairman shall cause notice of this determination, with the reasons therefor, to be published in the Federal Register, together with notice of commencement of proceedings under this chapter. (A) In proceedings under section 801(b)(2)(A) and (D), such petition may be filed during 1985 and in each subsequent fifth calendar year.