2.4. Application of the propulsion engine family and choice of parent propulsion engine U.K.
The engine manufacturer shall be responsible for defining those engines from his range which are to be included in an engine family.
A parent engine shall be selected from an engine family in such a way that its emissions characteristics are representative for all engines in that engine family. The engine incorporating those features that are expected to result in the highest specific emissions (expressed in g/kWh), when measured on the applicable test cycle, should normally be selected as the parent engine of the family.