5.1 Method A — Factor KA-AKA is determined in this method by means of careful measurements and a comprehensive analysis of thesystem, or on the basis of reliable operational experience in the field of application concerned. See 4.2.2.5.2 Method B — Factor KA-BIf no reliable data, obtained as described in 5.1, are available, even as early as the first design phase, it is possible to use the guideline values for KA as described in ISO 6336-6.6 Internal dynamic factor KvThe internal dynamic factor makes allowance for the effects of gear tooth accuracy grade as related to speed and load. High accuracy gearing requires less derating than low accuracy gearing.It is generally accepted that the internal dynamic load on the gear teeth is influenced by both design and manufacturing.The internal dynamic factor makes allowance for the effects of gear tooth accuracy and modifications as related to speed and load: