Methodology of automated study of the workload of a helicopter pilot

Currently, helicopters have become an integral part of the transport system, providing solutions to a wide range of tasks in the national economic activity. At the same time, advances in the technical equipment of helicopters make it possible to expand the areas of their operation, ensuring round-the-clock and all-weather use.

In turn, the demands of practice require further capacity building of helicopters in terms of power capacity, increasing the speed and range of flight, the weight of the cargo carried, the number of passengers, improving flight safety, improving the ergonomic characteristics of the crew's workplaces, etc. ^[1-3]. These areas are priorities for domestic and foreign helicopter companies ^{[4, 5]}.

The developed projects focus not only on the technical side of design, but also on taking into account the human factor in the "pilot-helicopter-environment" system, implemented by setting ergonomic technologies and applying an anthropocentric approach involving the development of new helicopters with the fullest possible consideration of the psychophysiological capabilities and characteristics of the flight crew ^[6-9]. At the same time, tools and methods are being developed to optimize the implementation of new types of activities, which are expected to significantly increase the efficiency of helicopter operation and flight safety ^[10-14].

It should be noted that information systems based on electronic indicators, sensor control systems, autopilots, indicators on the windshield, multifunctional controls, automated speech information systems, limit mode limitation systems, automatic navigation systems, etc. are currently being successfully operated ^[5-15].

At the same time, the experience of direct participation in the ergonomic support, modernization and creation of new helicopters, as well as monitoring of current practice requests and trends in the development of airborne aviation complexes shows that the introduction of complexes and systems on helicopters with a new element base, expanded functionality, adaptive control logic leads to an increase in the workload of crew members, which causes an increase in the risks of an accident or failure of the task ^[6-11].

The above allows us to conclude about the relevance of the development of a methodology for studying the workload of a pilot when testing helicopters and simulator training of flight personnel and the complex of technical means implementing it.

The methodology for studying the pilot's workload during helicopter tests is designed to obtain a quantitative assessment of the pilot's workload when performing both individual flight elements and the entire flight as a whole. With its help, it is possible to perform a comparative assessment of the level of the pilot's workload when performing various tasks for the examination of the helicopter and its components, as well as to determine the possibility of combining various test tasks in one flight.

The block diagram of the methodology for studying the workload of a helicopter pilot is shown in Figure 1.

Based on it, the study of the pilot's workload using the developed methodology can be divided into five main stages:

1) development of a workload research program;

2) modification of the helicopter by the developed complex of technical means for studying the reserves of attention of the helicopter pilot ("RVL-V");

3) determination of the pilot's workload using the RVL-V complex of technical means;

4) determination of the integral indicator of the pilot's workload;

5) drawing up a conclusion based on the results of the study.

Figure 1. Block diagram of the methodology for studying the pilot's workload during helicopter testing

Stage 1. Development of a workload research program.The purpose of the stage is to develop a program for the study of the pilot's workload, flight tasks and methodological guidelines for conducting research to determine the indicators of the pilot's workload.

At this stage, the test object is studied, the goals and objectives of the upcoming tests are considered, and the test program is analyzed.

The analysis of the test program is carried out by the test team with the participation of representatives of the head developer of the test object. During the analysis, a preliminary determination of the main flight modes (elements) and modes of operation of on-board equipment subject to examination during testing is made, the possibility and feasibility of studying the workload of the pilot at various stages of test flights is determined.

The result of the analysis of the test program is a decision on whether or not to conduct a study of the pilot's workload.

Based on the analysis of the test program and the decision to continue the study of the pilot's workload, the test team makes the final choice of modes for the study of the workload and draws up a program for its study at the training complex.

The result of the stage is a developed workload research program, flight tasks and methodological guidelines for them, or a decision on the inexpediency of studying the pilot's workload at the current stage of the helicopter life cycle.

Stage 2. Modification of the helicopter by the RVL-V complex of technical meansThe purpose of the stage is to finalize the semi-natural stand (training complex) with the RVL-V complex of technical means for conducting a study of the pilot's workload ^[16-20].

The hardware of the RVL-V hardware complex includes: a liquid crystal monitor with an independent power supply; a control panel; a controller; a microcomputer (microprocessor).

The 52PiCTD 5inch liquid crystal monitor is designed to present the pilot with signographic information on one of the seven programs implemented in the RVL-V hardware package.

The control panel is designed to implement the pilot's control actions (selection reaction) to the information displayed on the LCD monitor. There are three buttons on the remote control body. Each button is used to turn off signals of a certain color (programs No. 1, No. 2, No. 3) or to turn off signals in the form of certain geometric shapes (programs №4, №5, №6). In the case when the work is carried out according to programs No. 1, No. 2 and No. 3, when the button corresponding to the color of the displayed symbol is pressed, it is turned off, after which another symbol is displayed by random law, etc. In the case when the work is carried out according to programs No. 4, No. 5 and No. 6, when the button corresponding to the geometric shape of the symbol is pressed, it is turned off, after which another symbol is displayed by random law, etc.

The controller is designed to control the components of the RVL-V hardware complex, ensuring their joint functioning.

The microcomputer (microprocessor) is designed for:

to manage the RVL-V program by a statistician-operator in the process of assessing the pilot's attention reserves;

to create control commands by software for the issuance of a random law on a liquid crystal indicator of signographic information;

changes in the angular dimensions of the displayed signs;

 brightness and contrast level adjustments, between image and background,

determining the correctness of the pilot's response to the presented information;

fixing the duration of flight stages;

saving in the database the results of the program according to the "RVL-V" method, indicators of the activity of the cardiorespiratory system of the pilot and parametric flight information.

The modification of the helicopter by the RVL-V complex of technical means is carried out on the basis of the research program, taking into account the goals and objectives of the tests. To do this, the installation location of the complex of technical means in the simulator cabin is initially determined.

The choice of the installation location of the complex of technical means in the simulator cabin is the main task of this stage, since the validity of the developed methodology for assessing the workload of the pilot largely depends on it.

The installation location of the complex of technical means should be determined taking into account the requirements of GOST 19340-91, OST 1 00396-86, OST 1 00345-87 and oriented to the appropriate crew member.

The monitor from the complex of technical means must be installed in a place remote from the information field. The monitor should not be located near the group of main flight and navigation indicators on the instrument panels of helicopters or near the information control field of the on-board equipment of interest, otherwise it will lead to an involuntary distraction of the pilot's attention from solving the main task, which will inevitably affect its quality. At the same time, the location of the monitor should not limit or worsen the monitoring of the extra-cabin space for the pilot.

The choice of the installation location of the control panel from the RVL-V complex of technical means at the workplace of a crew member should be made on the basis of taking into account the peculiarities of his flight activity both during the normal operation of aircraft systems and aggregates, and in case of their failures. At the same time, it is necessary to ensure the minimum length of trajectories and the minimum number of working movements of the pilot.

The result of determining the installation location of the complex of technical means is the layout of the components of the complex in the helicopter cabin.

The equipment of the simulator with a set of technical means is made on the basis of the layout of the components of the complex in the cockpit of the helicopter by the developers of the semi-natural stand (simulator complex) with the participation of the head developer and the test team.

The result of equipping the simulator with a set of technical means is a protocol for finalizing a semi-natural stand (simulator complex) to assess the workload of the pilot.

The retrofitted semi-natural stand (gym complex) is subject to mandatory ergonomic examination, according to the results of which a protocol is drawn up.

Based on the protocols of revision and ergonomic examination, a conclusion is formed and issued based on the results of the completion of the semi-natural stand (training complex). If the conclusion is positive, then proceed to the next stage of the methodology, if negative, then the cycle of the stage repeats again.

The result of the stage is a conclusion on the readiness of the semi-natural stand (training complex) to conduct studies of the pilot's workload.

Stage 3. Determination of the pilot's workload using the RVL-V complex of technical means.The purpose of the stage is to obtain, using the RVL-V complex of technical means, a database of the workload of pilots at various stages of test flights ^[21-25].

Determination of the pilot's workload using a set of technical means is carried out according to the following algorithm:

1.                The pilot takes a workplace in the simulator cabin. At the command of the statistician operator, one of the 7 programs implemented in the RVL-V complex is launched.

2.                In a random place on the monitor screen, a signal is presented in the form of a circle of random color (green, red, yellow).

3. The geometric figure is displayed until the pilot presses one of the color signal selection buttons on the response panel. Pressing any of these buttons is a signal to turn off the presented figure and turn on a new color signal.

4. The following events are recorded: the presence of a response (pressing the button on the response panel); the truth of the response (pressing the button corresponding to the presented color).

5.                At the end of one minute from the moment the statistician-operator gives the command to start working according to the "Attention Reserves" method, the test signals are stopped.

6.                The following indicators are being determined:

the number of pilot responses to test signals (number of button clicks) in 1 min – KR;

the number of correct responses (the number of button presses corresponding to the required color) in 1 min – CPR;

the number of erroneous responses (the number of button presses that do not correspond to the requirements) in 1 min – CHOR;

The COR/CPR ratio is calculated.

7.                The comparison of the obtained and normative values of CPR and COR/CPR is made.

8.                The normative assessments are:

CPR ? 50;

COR/CPR ? 0.1.

9.                Depending on whether these conditions are met ((CPR?50),(COR/CPR?0.1)) or not, the operator decides whether it is possible to proceed to determining the average CPR value for the pilot under study.

10.           The following information is displayed on the remote control of the statistic operator (PC display screen):

number of responses (CR);

number of correct responses (CPR);

number of erroneous responses (COR);

the ratio of COR/CPR.

This information is stored in the database.

11. The number of introductory training sessions should be within 3 ...5 even if the conditions of clause 8 are met. Training stops if the conditions of clause 8 are met and the values of the CPR of two adjacent one–minute training cycles differ by no more than 5%: (|CPR i - CPR i+1| / CPR i ) ? 0.05. As a background value (KPRfon), the average value of the KPR for two adjacent training cycles is selected, for which the conditions of clause 8 are met and the value of the KPR differs by no more than 5%.

Based on the materials of the post-flight analysis of parametric flight information and the obtained indicators of the pilot's workload at various stages of test flights, a conclusion is formed and issued on the creditability of determining the workload of a helicopter pilot using a set of technical means. If the conclusion is positive, then proceed to the next stage of the methodology, if negative, then the cycle of the stage repeats again.

The result of the stage is a database of the workload of pilots at various stages of test flights and a conclusion on the creditworthiness of completed flight tasks.

Stage 4. Determination of the integral workload indicator.The purpose of the stage is to obtain a database of integral indicators of the workload of pilots at various stages of test flights ^{[12, 21-25]}.

The determination of integral indicators of the workload of pilots is carried out using the data of the pilot's workload obtained by expert evaluation and the algorithm for calculating the integral indicator of the workload of pilots.

The result of the stage is a database of integral indicators of the workload of pilots at various stages of test flights.

Stage 5. Execution of the Conclusion based on the results of the studyThe purpose of the stage is to issue a conclusion based on the results of the study of the workload of pilots.

The analysis of research materials is carried out in accordance with the current regulatory and technical documentation and legislation. The materials obtained during the research are analyzed, such as: a conclusion on the readiness of a semi-natural stand (simulator complex) for conducting research, a research program, flight tasks and methodological instructions for them, materials of onboard measurement tools; materials of objective control; a database of values of the integral indicator of the workload of pilots, etc. The analysis of completeness, reliability, objectivity and sufficiency of the materials obtained during the study of the pilot's workload is also carried out.

Based on the data array obtained during the analysis, a conclusion is formed and drawn up based on the results of the study, with recommendations for adjusting the flight part of the test program.

If the conclusion is positive, then the results of the study are used to adjust the helicopter test program, if negative, then they return to the first stage of research.

The result of the stage is a formed Conclusion based on the results of the study.

The use of the developed methodology for studying the pilot's workload during helicopter tests makes it possible to adequately assess the pilot's workload during test flights and use the results of the study for the most rational planning and adjustment of the (flight) test program ^[26-28].

* * *

In the general system of methodological support for helicopter testing, the initial use of the developed methodology begins at the stage of preliminary testing of the stage of development work on the creation of military aviation equipment. This makes it possible to use data on the pilot's workload already at the stage of factory tests, and a gradual increase, in the process of conducting state tests or state joint tests, of the amount of information about the pilot's workload at various stages of the flight and subsequent adjustment of test programs, provides shortening of time, increasing efficiency, reducing the volume and cost of tests.