Comparison of NASA-TLX scale, modified Cooper-Harper scale and mean inter-beat interval as measures of pilot mental workload during simulated flight tasks.

The sensitivity of NASA-TLX scale, modified Cooper-Harper (MCH) scale and the mean inter-beat interval (IBI) of successive heart beats, as measures of pilot mental workload (MWL), were evaluated in a flight training device (FTD). Operational F/A-18C pilots flew instrument approaches with varying task loads. Pilots' performance, subjective MWL ratings and IBI were measured. Based on the pilots' performance, three performance categories were formed; high-, medium- and low-performance. Values of the subjective rating scales and IBI were compared between categories. It was found that all measures were able to differentiate most task conditions and there was a strong, positive correlation between NASA-TLX and MCH scale. An explicit link between IBI, NASA-TLX, MCH and performance was demonstrated. While NASA-TLX, MCH and IBI have all been previously used to measure MWL, this study is the first one to investigate their association in a modern FTD, using a realistic flying mission and operational pilots. Practitioner summary: NASA-TLX scale, MCH scale and the IBI were evaluated in a flight training device. All measures were able to differentiate most task conditions and there was a positive correlation between NASA-TLX and MCH scale. An explicit link between IBI, NASA-TLX, MCH and performance was demonstrated. Abbreviations: ANOVA: Analysis of Variance; ECG: Electrocardiograph; F/A: fighter/attack; ft: feet; FTD: flight training device; G: Gravity; km: kilometer; m: meter; m/s: meters per second; MWL: mental workload; MCH: modified cooper-harper; NASA-TLX: NASA Task Load Index; NM: Nautical Mile; NN: normal-to-normal; IBI: inter-beat interval; ILS: Instrument Landing System; RR: R-Wave to R-Wave; SD: standard deviation; TTP: tactics, techniques and procedures; WTSAT: Weapon Tactics and Situation Awareness Trainer.

Fighter pilots' heart rate, heart rate variation and performance during instrument approaches.

Fighter pilots' heart rate (HR), heart rate variation (HRV) and performance during instrument approaches were examined. The subjects were required to fly instrument approaches in a high-fidelity simulator under various levels of task demand. The task demand was manipulated by increasing the load on the subjects by reducing the range at which they commenced the approach. HR and the time domain components of HRV were used as measures of pilot mental workload (PMWL). The findings of this study indicate that HR and HRV are sensitive to varying task demands. HR and HRV were able to distinguish the level of PMWL after which the subjects were no longer able to cope with the increasing task demands and their instrument landing system performance fell to a sub-standard level. The major finding was the HR/HRV's ability to differentiate the sub-standard performance approaches from the high-performance approaches. Practitioner Summary: This paper examined if HR and HRV were sensitive to varying task demands in a fighter aviation environment and if these measures were related to variations in pilot's performance.

Accuracy and Similarity of Team Situation Awareness in Simulated Air Combat.

BACKGROUND: Fighter pilots' Team Situation Awareness (TSA) has been studied from the perspective of TSA accuracy, which represents how closely the pilots' collective knowledge is aligned with the real world. When TSA accuracy is low, the pilots can have similarly or dissimilarly inaccurate SA. The concept of TSA similarity represents the similarity of team members' collective knowledge. This paper investigates how TSA accuracy and similarity of F/A-18 pilots are associated with performance.METHOD: Data were extracted from simulated air combat missions. Performance and TSA were investigated in 58 engagements. The accuracy and similarity of pilots' SA were elicited and performance was evaluated. TSA accuracy and similarity were analyzed with respect to the flights' performance, and the independent variables were events in which the flights initiated engagements with enemy aircraft versus events in which the flights were engaged by enemy aircraft.RESULTS: With the mentioned events as the main effect, there were statistically significant differences at all levels of TSA accuracy and similarity. With performance as the main effect, there were also significant differences at all levels of TSA accuracy and similarity. TSA accuracy and similarity were superior in offensive engagements and when engagements were successful.DISCUSSION: The main contribution of this paper is the extension of the concept of TSA similarity to air combat: both TSA similarity and accuracy were higher when the flight was engaging the enemy aircraft, compared to situations when the flight itself was being engaged. The results also suggest that low TSA accuracy and similarity have a statistically significantly negative impact on the flights' performance.Mansikka H, Harris D, Virtanen K. Accuracy and similarity of team situation awareness in simulated air combat. Aerosp Med Hum Perform. 2023; 94(6):429-436.

Normative Performance Measurement in Simulated Air Combat.

BACKGROUND: Normative performance (NP) describes the pilots adherence to tactics, techniques, and procedures (TTPs). Until now, there has not been a global NP measurement technique for beyond visual range (BVR) air combat, and the methodology and technology related to the evaluation of NP have fallen behind the pace of the overall technical progress of distributed mission operations (DMO) training.METHODS: Platform-independent core air combat tasks were identified. The execution of these tasks is directed with TTPs. BVR air combat missions were flown in a DMO simulator system and the design NP was varied between missions. Observers viewed debriefs of these missions and attempted to identify TTP-regulated air combat tasks. Once identified, they scored the pilots NP in those tasks. The scoring was based on the level of TTP adherence and the impact a nonadherence had on the mission accomplishment.RESULTS: All observers were able to identify most of the TTP-regulated air combat tasks. There was a strong positive correlation between the observed and design NP scores. The overall Kappa indicated a fair agreement between the observers. The percentage of observers NP assessments which agreed with the design NP varied from 49.60 to 85.28% in different air combat missions. On average, 73.9%6 of the observers NP scores agreed with the design NP scores.CONCLUSIONS: Observers were able to accurately identify TTP-regulated tasks and score NP of these tasks during an air combat debrief. There was a moderate agreement between the observers NP scores.Mansikka H, Virtanen K, Mkinen L, Harris D. Normative performance measurement in simulated air combat. Aerosp Med Hum Perform. 2021; 92(11):908-912.

Team situation awareness accuracy measurement technique for simulated air combat - Curvilinear relationship between awareness and performance.

A new technique for the assessment of Team Situation Awareness (TSA) accuracy based upon post task Critical Decision Method structured interviews was developed and tested using 39 combat-ready F/A-18 pilots. Pilots undertook a number of simulated air combat scenarios, flying in flights of four aircraft against a formation of enemy aircraft. Results showed a strong curvilinear relationship where high TSA accuracy resulted in higher performance in some areas of air combat, measured with friendly losses and kills. There were diminishing returns in performance as TSA accuracy increased. This may explain why previous studies on air combat have found relatively weak relationships between situation awareness and performance where the relationship has been assumed to be linear.

Direct Least Square Fitting of Hyperellipsoids.

This paper presents two new computationally efficient direct methods for fitting n-dimensional ellipsoids to noisy data. They conduct the fitting by minimizing the algebraic distance in subject to suitable quadratic constraints. The hyperellipsoid-specific (HES) method is an elaboration of existing ellipse and 3D ellipsoid-specific fitting methods. It is shown that HES is ellipsoid-specific in n-dimensional space. A limitation of HES is that it may provide biased fitting results with data originating from an ellipsoid with a large ratio between the longest and shortest main axis. The sum-of-discriminants (SOD) method does not have such a limitation. The constraint used by SOD rejects a subset of non-ellipsoidal quadrics, which enables a high tendency to produce ellipsoidal solutions. Moreover, a regularization technique is presented to force the solutions towards ellipsoids with SOD. The regularization technique is compatible also with several existing 2D and 3D fitting methods. The new methods are compared through extensive numerical experiments with n-dimensional variants of three commonly used direct fitting approaches for quadratic surfaces. The results of the experiments imply that in addition to the superior capability to create ellipsoidal solutions, the estimation accuracy of the new methods is better or equal to that of the reference approaches.

Fighter pilots' heart rate, heart rate variation and performance during an instrument flight rules proficiency test.

Increased task demand will increase the pilot mental workload (PMWL). When PMWL is increased, mental overload may occur resulting in degraded performance. During pilots' instrument flight rules (IFR) proficiency test, PMWL is typically not measured. Therefore, little is known about workload during the proficiency test and pilots' potential to cope with higher task demands than those experienced during the test. In this study, fighter pilots' performance and PMWL was measured during a real IFR proficiency test in an F/A-18 simulator. PMWL was measured using heart rate (HR) and heart rate variation (HRV). Performance was rated using Finnish Air Force's official rating scales. Results indicated that HR and HRV differentiate varying task demands in situations where variations in performance are insignificant. It was concluded that during a proficiency test, PMWL should be measured together with the task performance measurement.