Quantitative assessment of pilot-endured workloads during helicopter flying emergencies: an analysis of physiological parameters during an autorotation

The procedures to be performed after sudden engine failure of a single-engine helicopter impose high workload on pilots. The maneuver to regain aircraft control and safe landing is called autorotation. The safety limits to conduct this maneuver are based on the aircraft height versus speed diagram, which is also known as "Dead Man’s Curve”. Flight-test pilots often use subjective methods to assess the difficulty to conduct maneuvers in the vicinity of this curve. We carried out an extensive flight test campaign to verify the feasibility of establishing quantitative physiological parameters to better assess the workload endured by pilots undergoing those piloting conditions. Eleven pilots were fully instrumented with sensors and had their physiological reactions collected during autorotation maneuvers. Our analyses suggested that physiological measurements (heart rate and electrodermal activity) can be successfully recorded and useful to capture the most effort-demanding effects during the maneuvers. Additionally, the helicopter’s flight controls displacements were also recorded, as well as the pilots’ subjective responses evaluated by the Handling Qualities Rate scale. Our results revealed that the degree of cognitive workload was associated with the helicopter’s flight profile concerning the Height-Speed diagram and that the strain intensity showed a correlation with measurable physiological responses. Recording flight controls displacement and quantifying the pilot's subjective responses show themselves as natural effective candidates to evaluate the intensity of cognitive workload in such maneuvers.

Structural Health Monitoring of Electro-Mechanical Actuators in Aviation: Recent Breakthroughs and Further Challenges

Electrical actuation systems have recently been introduced in aviation pursuing the concepts of More Electric Aircraft. Instead of employing hydraulic pipelines, Electro-Mechanical Actuator (EMA) transfers the power by “wires” with a consequent improvement of the aircraft actuation performance. However, the integration of linear electromechanical actuators is promising yet challenging in safety critical systems. Within this context, this work critically reviews electromechanical actuators currently available for aerospace application, the limits for their upcoming deployment and the different solutions to achieve an on-condition maintenance to reduce any safety risk during lifetime. First of all, the typical conversion mechanism adopted so far are briefly described with emphasis on the most suited for aerospace applications. A further insight is given to failure modes of these systems, which dramatically contrast the countless inherent advantages thereof. A particular attention is given to the jamming of the driven load, which is a critical mechanical transmission failure in many applications such as primary flight controls or landing gears extension and steering. Finally, the focus is moved to possible strategies to avoid any hazard induced by this failure. In particular, any structural alteration which is prone to induce jamming can be monitored towards the establishment of a predictive maintenance. Different possibilities are available in the way to timely assess the bearing of inner EMA surfaces where screwing is enabled.

Design and Evaluation of Fault-Tolerant Electro-Mechanical Actuators for Flight Controls of Unmanned Aerial Vehicles

Electro-mechanical actuators (EMAs) are a primary actuation technology for unmanned aerial vehicles (UAVs). Intensive research has been conducted for designing and evaluating fault-tolerant EMAs for flight controls of UAVs to ensure their compliance with new airworthiness requirements for safe operation over civilian zones. The state-of-the-art research involves several fault-tolerant architectures for EMAs based on parallel electric motors or a single motor with internal fault-tolerant features. In this study, a fault-tolerant architecture is introduced, comprised of two serial electric motors driven by two isolated controllers and a health monitoring system. The procedures of developing various fault-tolerant features are discussed with a deep focus on designing health monitoring functions and evaluating their influence on the overall actuator stability and availability. This work has been conducted and evaluated based on operational data for ALAADy: a heavy gyrocopter-type UAV at DLR (German Aerospace Center).

ANALYSIS OF SPACECRAFT TELEMETRY INFORMATION USING THE KNOWLEDGE BASE, REPLENISHED DURING THEIR OPERATION

The method for intellectualizing the analysis of telemetric information from spacecraft arriving at ground-based flight controls is discusses. The features of state control during the spacecraft operation are formulated. The basic concepts, terms and basic properties of time series are presented, the definition of the physical meaning of the characteristic quantities for the spacecraft flight control process is given. The use of the mathematical apparatus for the analysis of time radars is substantiated in solving problems of telemetry support in the process of controlling the flight of spacecraft. A mathematical apparatus for analyzing time series is proposed to identify the actual trend. An approach to solving the problem of predicting the state of a spacecraft based on a comparative version is presented. Requirements for the intelligent analysis algorithm are presented and an integrated algorithm is proposed, a method based on time series.