The use of offshore wind farms in Europe to provide a sustainable alternative energy source is now considered normal. Particularly in the North Sea, a large number of wind farms exist with a significant distance from the coast. This is becoming standard practice as larger areas are required to support operations. Efficient transport and monitoring of these wind farms can only be conducted using helicopters. As wind turbines continue to grow in size, there is a need to continuously update operational requirements for these helicopters, to ensure safe operations. This study assesses German regulations for flight corridors within offshore wind farms. A semi-empirical wind turbine wake model is used to generate velocity data for the research flight simulator AVES. The reference offshore wind turbine NREL 5 MW has been used and scaled to represent wind turbine of different sizes. This paper reports result from a simulation study concerning vortex wake encounter during offshore operations. The results have been obtained through piloted simulation for a transport case through a wind farm. Both subjective and objective measures are used to assess the severity of vortex wake encounters.

Helicopters are used for offshore wind farms for maintenance and support flights. The number of helicopter operations is increasing with the expansion of offshore wind energy, which stresses the point that the current German regulations have not yet been validated through scientific analysis. A collaborative research project between DLR, the Technical University of Munich, the University of Stuttgart and the University of Tübingen has been conducted to examine the sizes of the flight corridors on offshore wind farms and the lateral safety clearance for helicopter hoist operations at offshore wind turbines. This paper details the results of piloted helicopter simulations in a realistic offshore wind farm scenario. The far-wake of rotating wind turbines and the near-wake of non-rotating wind turbines have been simulated with high-fidelity computational fluid dynamics under realistic turbulent inflow conditions. The resulting flow fields have been processed by superposition during piloted simulations in the research flight simulator AVES to examine the flight corridors in transit flights and the lateral safety clearance in hovering flights. The results suggest a sufficient size for the flight corridor and sufficient lateral safety clearance at the offshore wind turbines in the considered scenarios.

The operation of helicopters on ships is one to most challenging tasks due to adverse weather conditions, the lack of visible cues, turbulent airwakes behind the ship and a moving confined landing spot on the ship. Currently, only a very limited number of pilot assistance systems are available to ease helicopter ship deck landings. The focus of this paper is the evaluation of a Head-DownDisplay(HDD),aHead-MountedDisplay(HMD)andtwodifferentAttitudeCommand Attitude Hold (ACAH) flight control architectures for ship deck landings based on piloted simulation. A ship deck landing scenario at the research flight simulation facility Air Vehicle Simulator (AVES) has been extended to include turbulent ship airwakes from high-fidelity Computational Fluid Dynamics (CFD). The pilot assistance systems have been implemented at the simulator and evaluated by four helicopter pilots. In particular, the results show a favorable potential of the Head-Mounted Display and the flight control architectures.

This paper describes the development and implementation of newly designed helicopter ship deck landing control modes and their evaluation in a piloted simulation study. The ship deck landing modes are embedded in a model following controller architecture. The employed control design is a complete model-following control system which imposes the desired command model dynamics on the controlled helicopter. Different command types combined with various hold functions are implemented to make the task easier for the pilots. Three basic command types and three advanced command types, one without ship communication and two with ship communication, are implemented. A piloted simulation study was performed in a simulator to evaluate and compare the implemented control modes within a complete maritime scenario design. The evaluation of control modes is based on the success of helicopter ship deck landings which is assessed by a quantitative as well as a qualitative assessment. Simulation results demonstrate that the advanced command types improved the task performance as well as reduced the pilot workload extensively in comparison to the basic command types.