(a) The prescribed acceptable quality level is 40 percent.

(b) A failed engine is one whose final test results pursuant to §91.509(b), for HC + NOX. exceed the applicable family emission level.

(c) The manufacturer must test engines comprising the test sample until a pass decision is reached for HC + NOX or a fail decision is reached for HC + NOX. A pass decision is reached when the cumulative number of failed engines, as defined in paragraph (b) of this section, for HC + NOX is less than or equal to the pass decision number, as defined in paragraph (d) of this section, appropriate to the cumulative number of engines tested. A fail decision is reached when the cumulative number of failed engines for HC + NOX is greater than or equal to the fail decision number, as defined in paragraph (d) of this section, appropriate to the cumulative number of engines tested.

(d) The pass and fail decision numbers associated with the cumulative number of engines tested are determined by using the tables in Appendix A to this subpart, “Sampling Plans for Selective Enforcement Auditing of Marine Engines,” appropriate to the projected sales as made by the manufacturer in its report to EPA under §91.504(c)(1). In the tables in Appendix A to this subpart, sampling plan “stage” refers to the cumulative number of engines tested. Once a pass or fail decision has been made for HC + NOX. the number of engines with final test results exceeding the emission standard for HC + NOX shall not be considered any further for the purposes of the audit.

(e) Passing or failing of an SEA occurs when the decision is made on the last engine required to make a decision under paragraph (c) of this section.

(f) The Administrator may terminate testing earlier than required in paragraph (c) of this section.