Strutt|Criteria|Ratings|Sound Level|Noy calculates the noisiness rating (noys) of the current row of the active sheet and inserts it into Column D of the active row.
The user has the option of calculating the Noy rating numerically (based on the values in Table 13 of the standard) or by utilising the formula in the standard (combined with the constants in Table 14). In theory, calculating the Noy rating based on Table 13 should give the same result as the equation; but slight discrepencies between the two have been found in some instances.
Reference: ISO 3891 (1978) Acoustics - Procedure for Describing Aircraft Noise Heard on the Ground