Ph.D. Proposal

Eleni Sotiropoulos

(Advisor: Professor Mavris)

Methodology to Enable Scenario-Based Training of Accident-Prone Vortex Ring State (VRS) Encounters in Helicopter Flight Simulators

Friday, June 7

9:00 a.m.

Collaborative Visualization Environment (CoVE)

Weber Space and Technology Building (SST II)

and

Microsoft Teams

Abstract

From 2008 to 2021, 48 helicopter accidents have involved Vortex Ring State (VRS) encounters in the United States. Ambitious rotorcraft safety improvement objectives have been set by the helicopter community for the current decade, which will require to mitigate VRS-induced accidents. However, due to the inherent risks, training for fully developed VRS during actual flights is discouraged. Thus, simulators could provide a safer alternative for pilot training, assuming that they accurately replicate the helicopter's flight dynamics during VRS. To be able to perform VRS Scenario-Based Training in flight simulators, the latter's ability to represent VRS onset and recovery must be evaluated. However, the 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. Hence, it is necessary to develop a more objective fidelity assessment of flight simulators in VRS.

The first step requires building and evaluating non-real-time simulations. To that end, we will develop simulations using two types of inflow models in Flightlab: one real-time dynamic inflow akin to those found in flight simulators, the other a higher fidelity inflow model (VVPM) unsuited for real-time simulation. These two models can then be compared with one another and with flight test data to validate the use of the VVPM-based one to supplement flight test data.

The second step focuses on VRS onset. A flight test is performed to obtain data on the helicopter's behavior in VRS. Then, assuming the behavior in VRS of the Flightlab model developed in the previous step is deemed acceptable, it can be used along with the flight test data to assess, in flight simulators, the accuracy of the representation of the VRS onset. This entails defining a set of metrics to use for the evaluation.

Following the same approach as the previous step, the third step centers on VRS recovery techniques, using data from a flight test and from modeling results to test the accuracy of recovery techniques modeling in flight simulators. Here as well, a set of metrics must be defined to evaluate simulators' performance for this task. Additionally, these experiments provide insight into the

effectiveness and potential limitations of the different techniques for VRS recovery.

Once the accuracy of the simulator has been determined, we can develop VRS-inducing scenarios based on accidents and suitable to the flight simulator's performance. A group of pilots can then test this set of scenarios to demonstrate its use in VRS accident prevention Scenario-Based Training, by evaluating pilots' VRS awareness, avoidance, detection, and recovery during the simulations.

Committee

·         Prof. Dimitri Mavris – School of Aerospace Engineering (advisor)

·         Prof. Daniel P. Schrage – School of Aerospace Engineering

·         Prof. Marilyn Smith – School of Aerospace Engineering

·         Dr. Alexia Payan – School of Aerospace Engineering

·         Mr. Charles C. Johnson – Federal Aviation Administration (FAA)