If the standard-setting part requires durability testing, you must accumulate service in a way that represents how you expect the engine to operate in use. You may accumulate service hours using an accelerated schedule, such as through continuous operation or by using duty cycles that are more aggressive than in-use operation, subject to any pre-approval requirements established in the applicable standard-setting part.
(a) Maintenance. The following limits apply to the maintenance that we allow you to do on an emission-data engine:
(1) You may perform scheduled maintenance that you recommend to operators, but only if it is consistent with the standard-setting part's restrictions.
(2) You may perform additional maintenance only as specified in § 1065.410 or allowed by the standard-setting part.
(b) Emission measurements. Perform emission tests following the provisions of the standard setting part and this part, as applicable. Perform emission tests to determine deterioration factors consistent with good engineering judgment. Evenly space any tests between the first and last test points throughout the durability period, unless we approve otherwise.
[70 FR 40516, July 13, 2005, as amended at 73 FR 37315, June 30, 2008]