One of the major causes of failures of mechanical systems (e.g. drive trains, pitch systems, and yaw systems) in wind turbines is insufficient knowledge of the loads acting on these components. The objective of this pre-normative project is to set up a methodology that enables better specification of design loads for the mechanical components. The design loads will be specified at the interconnection points where the component can be "isolated" from the entire wind turbine structure (for gearboxes for instance the interconnection points are the shafts and the attachments to the nacelle frame). The focus will be on developing guidelines for measuring load spectra at the interconnection points during prototype measurements and to compare them with the initial design loads. Ultimately, the new procedures for the mechanical components will be brought at the same high level as the state-of-the-art procedures for designing and testing rotor blades and towers which are critical to safety. A well balanced consortium, consisting of a turbine manufacturer, component manufacturer, certification institute, and R&D institutes will describe the current practice for designing and developing mechanical components. Based on this starting point, the project team will draft improved procedures for determining loads at the interconnection points. The draft procedures will be applied to three case studies with each a different focus, viz. determining loads at the drive train, pitch system, and yaw system; the latter one taking into account complex terrain. The procedures will be assessed by the project team and depending on the outcome the procedures will be updated accordingly and disseminated. All partners will incorporate the new procedures in their daily practices for designing turbines and components, certifying them, and carrying out prototype measurements. Project results will be submitted to relevant standardisation committees.