In making that determination, the manufacturer must use good engineering judgment (considering, for example, all engine configurations and power ratings within the engine family and the range of installation options allowed). By requiring manufacturers to test the worst-case engine, we can be sure that all engines within the engine family are complying with emission standards for the least cost (as measured by the number of tests required). Manufacturers may request the separation of the dissimilar calibrations into separate engine families. This may be appropriate, for example, if a manufacturer feels that an engine family is grouped too broadly or that the worst-case emission data engine underestimates the emission credits available under the ABT provisions.
K. Production-Line Testing
One of the challenges of serial engine production is ensuring that each engine produced has the same emission characteristics as the original certification engine. We are finalizing a requirement for manufacturers to conduct production line testing (PLT). The general object of a PLT program is to show, with reasonable certainty, whether certification designs have been translated into production engines that meet applicable standards (or FELs) at the time of production, before excess emissions are generated in use. PLT is performed on a regular basis during the year by the engine manufacturer according to our criteria.
With PLT testing, a manufacturer selects engines from its production line for confirmatory testing. In general, a manufacturer must test one percent of its total projected annual U.S. marine diesel engine sales (propulsion and auxiliary) for each category each year. We believe that a one percent sampling rate is appropriate for the marine diesel engine industry because of its low production volumes, and that a higher sampling rate would be overly burdensome for this industry. We are not specifying a minimum number of tests for Category 1 engines. If a manufacturer sells fewer than 100 Category units in the United States in a given year, it is not required to do any PLT testing for those engines that year. For Category 2 engines, a manufacturer must conduct a minimum of one PLT test per year. Thus, for manufacturers with sales of less than 100 Category 2 engines in a given year, one test is required that year. For purposes of calculating the number of tests required, Category 1 and Category 2 annual engine sales must be considered separately.
The manufacturer selects a random sample of test engines that is representative of annual production. We reserve the right to reject any engines selected by manufacturers if we determine that such engines do not represent production engines. Engines selected should cover the broadest range of production possible, and from year to year should be varied to cover all engine families if possible. Tests should also be distributed evenly throughout the model year, to the extent possible.
Manufacturers must conduct emission testing of PLT engines in accordance with the applicable federal testing procedures. Compliance with the NTE provisions must be demonstrated as part of PLT testing. The results must be communicated to us in periodic reports that summarize emissions results, test procedures, and events such as the date, time, and location of each test. These reports allow us to continually monitor the PLT data. Reports must be submitted each quarter. If no testing is performed during the period, no report is required.
Under this testing scheme, if an engine fails a production line test, the manufacturer must test two additional engines out of either the next two days' production or the next fifteen engines produced in that engine family in accordance with the applicable federal testing procedures. This dual approach to testing additional engines accounts for variations in production volumes. If production volumes are high, then we believe the two-day provision will allow for the orderly selection of additional test engines. Likewise, if production volumes are low, then the provision allowing the engines to be selected from the next fifteen produced will allow for orderly selection. When the average of the three test results, for any pollutant, are greater than the applicable standard or FEL for any pollutant, the manufacturer fails the PLT for that engine family. Such failures must be reported to us within two working days of the determination of a failure. Note that compliance with the standards is required of every covered engine. Thus, every engine failing a PLT test is considered noncompliant with the standards and must be brought into compliance. Using the average of three tests to determine compliance with the PLT program serves only as a tool to decide when it is appropriate to suspend or revoke the certificate of conformity for that engine family, and is not meant to imply that not all engines have to comply with the standards.
In the PLT program, the Administrator can suspend or revoke the manufacturer's certificate of conformity, in whole or in part, thirty days after we determine that an engine family is noncompliant, or if the engine manufacturer's report reveals that the PLT tests were not performed correctly. During the thirty-day period after we establish noncompliance, we will coordinate with the manufacturer to facilitate the approval of the required production line remedy to eliminate the need to halt production as much as possible. The manufacturer must then address the noncompliance for the engines produced prior to the suspension or revocation of the certificate of conformity (for example, by bringing them into compliance or removing them from service). We can reinstate the certificate after a suspension, or reissue one after a revocation, if the manufacturer demonstrates through its PLT program that improvements, modifications, or replacements have brought the engine family into compliance. The regulations include hearing provisions that provide a mechanism to resolve disputes between manufacturers and us regarding a suspension or revocation decision based on noncompliance with the PLT. It is important to point out that we retain the legal authority to inspect and test engines if problems arise in the PLT program. Note also that the definition of "failure" of the PLT is limited to the PLT program, and does not define failure or noncompliance for other purposes. It is based in part on the severity of the result of a failure (suspension or revocation of a certificate) and is not meant to limit in any way the overall obligation of the manufacturer to produce engines that meet the standard.
We recognize the need for a PLT program that does not impose an unreasonable burden on manufacturers. Therefore, consistent with the requirement that testing be required on one percent of total marine diesel engine production for each category, no PLT is required for manufacturers whose Category 1 marine diesel engines sales are less than 100 per year. This is because companies with such low sales are unlikely to have in-house testing facilities, and requiring such companies to send an engine to an independent test facility for PLT purposes may be too burdensome. Note that companies exempt from the PLT program are not exempt from other certification and compliance provisions. Engines exempt from the PLT program must still meet the emission limits as produced and in use. We reserve the right to conduct an SEA on any manufacturer with engines certified to the requirements of this final rule. In addition, we are not extending this flexibility provision to the PLT program for Category 2 marine diesel engines, since they are typically produced in very small volumes.
