(a) This subpart prescribes rules in addition to those in other parts of this chapter for the maintenance, preventive maintenance, and alterations for each certificate holder as follows:
(1) Aircraft that are type certificated for a passenger seating configuration, excluding any pilot seat, of nine seats or less, shall be maintained under parts 91 and 43 of this chapter and §135.415, 135.417, 135.421 and 135.422. An approved aircraft inspection program may be used under 135.419.
(2) Aircraft that are type certificated for a passenger seating configuration, excluding any pilot seat, of ten seats or more, shall be maintained under a maintenance program in §135.415, 135.417, 135.423 through 135.443.
(b) A certificate holder who is not otherwise required, may elect to maintain its aircraft under paragraph (a)(2) of this section.
(c) Single engine aircraft used in passenger-carrying IFR operations shall also be maintained in accordance with 135.421 (c), (d), and (e).
(d) A certificate holder who elects to operate in accordance with 135.364 must maintain its aircraft under paragraph (a)(2) of this section and the additional requirements of Appendix G of this part.