Division 2.7.21 Method for the Calculation of Helicopter Noise

For the calculation of helicopter noise, the same calculation method used for fixed-wing aircraft (outlined in Section 2.7.14) may be used, provided helicopters are treated as propeller aircraft and engine-installation effects, associated with jet aircraft are not applied. Tables of entries for two different data sets are presented in Annex I (Tables I-18 I-27).