Investigation into the Fidelity Assessment and Use of Helicopter Flight Simulators in Vortex Ring State (VRS) Accident Prevention Training

Files
Thesis_ES_10-2025_low compression.pdf (17.38 MB)
Author(s)
Sotiropoulos-Georgiopoulos, Eleni
Advisor(s)
Editor(s)
Associated Organization(s)
Organizational Unit
Organizational Unit
Daniel Guggenheim School of Aerospace Engineering
The Daniel Guggenheim School of Aeronautics was established in 1931, with a name change in 1962 to the School of Aerospace Engineering
Series
Collections
Theses and Dissertations
Supplementary to:
Permanent Link
https://hdl.handle.net/1853/78673
Abstract
From 2008 to 2021, 48 helicopter accidents in the United States likely involved Vortex Ring State (VRS) encounters. The helicopter community has set ambitious rotorcraft safety improvement objectives for the current decade, which will therefore require mitigating VRS-induced accidents. However, due to the risks involved, training for fully developed VRS during actual flights is discouraged. Thus, simulators could offer a safer alternative for pilot training, provided they accurately replicate helicopter flight dynamics during this phenomenon. To enable effective VRS accident-prevention training in flight simulators, their ability to represent VRS onset and recovery must be assessed. However, current qualification standards for VRS simulation remain subjective, raising uncertainties about the simulator's suitability for pilot training and the potential risks associated with negative transfers of skills from the simulator to the helicopter. This underlines the need for an objective fidelity assessment framework specific to VRS. To that end, evaluation criteria are defined based on the results of a dedicated flight test campaign performed on a Robinson R66, as well as flight test data from the literature. Methods are then developed to evaluate three simulation models against these criteria: the H125 reduced motion platform VR simulator from Loft Dynamics, and two H125 FLIGHTLAB simulation models implemented for this research, one with the Viscous Vortex Particle Method (VVPM) inflow, and the other with a dynamic inflow model. Once equipped with tools to determine the accuracy of a given simulator, this work designs VRS-inducing scenarios based on accidents and adapted to the simulator's fidelity and capabilities. A group of pilots then tests this set of scenarios. To demonstrate its use in VRS accident prevention Scenario-Based Training, we evaluate pilots' VRS awareness, avoidance, detection, and recovery during the simulations. In addition, to enhance the simulator flight training experience of both pilots and instructors, a framework is developed to evaluate pilots' performance in VRS recoveries. The outcomes of this research provide methods for evaluating simulator fidelity in VRS and improving VRS accident-prevention pilot training. The findings aim to advance simulation technologies and training strategies for enhanced rotorcraft safety.
Sponsor
Date
2025-07-30
Extent
Resource Type
Text
Resource Subtype
Dissertation
Rights Statement
Rights URI