Description: time spent on the preventive maintenance of the engine; Name: preventive maintenance period
Description: part of maintenance time when preventive maintenance is carried out on an item, including technical, logistic and internal administrative delay; Name: preventive maintenance time
Description: ten times the logarithm to the base 10 of the ratio of the sound power of a source, p, to a reference value, p0, expressed in decibels; Name: sound output level