Supersonic engines.

The following standards apply to new engines installed in supersonic airplanes: (a) Smoke. Engines of a type or model for which the date of manufacture was on or after January 1, 1984, may not have a characteristic level for smoke number exceeding an emission standard that is the lesser of 50 or the following: SN = 83.6·rO − 0.274 (b) [Reserved] (c) HC. Engines of a type or model for which the date of manufacture was on or after January 1, 1984, may not have a characteristic level for HC exceeding the following emission standard in g/kN rated output: HC = 140·0.92 rPR (d) CO. Engines of a type or model for which the date of manufacture was on or after July 18, 2012, may not have a characteristic level for CO exceeding the following emission standard in g/kN rated output: CO = 4550·rPR −1.03 (e) NO X Engines of a type or model for which the date of manufacture was on or after July 18, 2012, may not have a characteristic level for NO X engines exceeding the following emission standard in g/kN rated output: NO X = 36+2.42·rPR