(a) EPA shall annually identify engine families and those configurations within families which the manufacturers must then subject to in-use testing. For each model year, EPA may identify the following number of engine families for testing, based on the number of the manufacturer's engine families to which this subpart is applicable produced in that model year:

(1) For manufactures with three or fewer engine families, EPA may identify a single engine family.

(2) For manufacturers with four or more engine families, EPA may identify a number of engine families that is no greater than twenty-five percent of the number of engine families to which this subpart is applicable that are produced by the manufacturer in that model year.

(b) For each engine family identified by EPA, engine manufacturers shall perform emission testing of an appropriate sample of in-use engines from each engine family. Manufacturers shall submit data from this in-use testing to EPA.

(c) Number of engines to be tested. An engine manufacturer shall test in-use engines from each engine family identified by EPA. Engines to be tested shall have accumulated between half and three-quarters of the family's useful life. The number of engines to be tested by a manufacturer will be determined by the following method:

(1) A minimum of four (4) engines per family provided that no engine fails any standard. For each failing engine, two more engines shall be tested until the total number of engines equals ten (10).

(2) For engine families of less than 500 engines for the identified model year or for engine manufacturers who make less than or equal to 2,000 for that model year, a minimum of two (2) engines per family provided that no engine fails any standard. For each failing engine, two more engines shall be tested until the total number of engines equals ten (10).

(3) If an engine family was certified using carry over emission data and has been previously tested under paragraph (c) (1) or (2) of this section (and EPA has not ordered a recall for that family), then only one engine for that family must be tested. If that one engine fails any pollutant, testing must be conducted as outlined at paragraph (c) (1) or (2) of this section, whichever is appropriate.

(d) At the discretion of the Administrator, an engine manufacturer may test more engines than the minima described in paragraph (c) of this section or may concede failure before testing a total of ten (10) engines.

(e) The Administrator will consider failure rates, average emission levels and the existence of any defects among other factors in determining whether to pursue remedial action under this subpart. The Administrator may order a recall pursuant to §§91.807-91.814 before testing reaches the tenth engine.

(f) The Administrator may approve an alternative to manufacturer in-use testing, where:

(1) Engine family production is less than or equal to 200 per year; or

(2) Engines cannot be obtained for testing because they are used substantially in craft which are not conducive to engine removal such as large vessels where the engine can not be removed without dismantling either the engine or the vessel; or

(3) Other compelling circumstances associated with the structure of the industry and uniqueness of marine engine applications. Such alternatives shall be designed to determine whether the engine family is in compliance in-use.

(g) Collection of in-use engines. The engine manufacturer shall procure in-use engines which have been operated for between half and three-quarters of the engine's useful life. The engine manufacturer may test engines from more than one model year in a given year. The manufacturer shall begin testing within twelve calendar months after receiving notice that EPA has identified a particular engine family for testing and shall complete testing of such engine family within twelve calendar months from the start of such testing. Test engines may be procured from sources associated with the engine manufacturer (i.e., manufacturer established fleet engines, etc.) or from sources not associated with the manufacturer (i.e., consumer-owned engines, independently-owned fleet engines, etc.).

[61 FR 52102, Oct. 4, 1996, as amended at 67 FR 68340, Nov. 8, 2002]