CFR

Title 1 - General Provisions
Title 2 - Grants and Agreements
Title 3 - The President
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Title 38 - Pensions, Bonuses, and Veterans' Relief
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Title 42 - Public Health
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Title 44 - Emergency Management and Assistance
Title 45 - Public Welfare
Title 46 - Shipping
Title 47 - Telecommunication
Title 48 - Federal Acquisition Regulations System
Title 49 - Transportation
Title 50 - Wildlife and Fisheries

91.117—Certification procedure—service accumulation.

(a) (1) Any engine required to be tested under § 91.118 must be operated with all emission control systems operating properly for a period sufficient to stabilize emissions prior to such testing.

(2) A manufacturer may elect to consider emission levels as stabilized when the test engine has accumulated 12 hours of service.

(b) No maintenance, other than recommended lubrication and filter changes, may be performed during service accumulation without the Administrator's approval.

(c) Service accumulation is to be performed in a manner using good engineering judgment to ensure that emissions are representative of production engines.

(d) The manufacturer must maintain, and provide to the Administrator if requested, records stating the rationale for selecting a service accumulation period different than 12 hours and records describing the method used to accumulate hours on the test engine(s).

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