Introduction: The Institute of Aerospace Medicine provides design consultancy on aircraft-aircrew compatibility on a number of fixed-wing as well as rotary-wing aircrafts during various stages of development. Till date, the cockpit compatibility of aircrew has been determined based on the percentile concept. Percentiles, though useful when dealing with a single parameter, pose major design and fitment problems when considering multiple parameters simultaneously as in aircraft cockpit design. The concept of multivariate analysis has been the solution which the aviation industry the world over has accepted in overcoming this problem. This paper presents the Institute of Aerospace Medicine initial foray into the field of multivariate analysis, specifically principal component analysis (PCA) to achieve desired aircrew fitment in the aircraft cockpit right from the design stage. Materials and Methods: The fighter aircraft of the near future is being designed using the anthropometric parameters available in the IAF aircrew anthropometry survey 2013. Of the 57 parameters available, six parameters critical to the design of the cockpit were subject to PCA to derive three principal components. About 96% confidence ellipse was drawn on the plot of the principal components. From this, along the different axes, 21 boundary individuals were identified defining the extreme individuals in various combinations of the six parameters. Discussion: The use of more than 2 parameters is not amenable to sequential use of percentiles. As the number of parameters considered increases, it leads to reduced fitment percentage. The use of PCA allows consideration of critical parameters together at one go. The design aim is changed from the 3rd to 97th percentile to an overall aim of fitting 96% of the target population in the cockpit. The boundary individual’s entire anthropometry data are used to create boundary manikins for use in computer-aided design models. The fitment of these boundary individuals ensures that if these individuals fit, all others would fit in the cockpit. This concept brings about a paradigm shift in the aircrew-aircraft compatibility in the aviation industry in India.

Introduction: Sustained operations are the future of any advanced Air Force, which involve round the clock flying operations over a prolonged period. Such operations have the potential of disrupting normal sleep cycle and may cause fatigue among aircrew and ground duty personnel. It is well known that fatigue among crew member is a significant risk to aerospace safety. The present study was hence undertaken to quantify the subjective fatigue and its effects, among the personnel involved in a simulated exercise using Sustained Operations Assessment Profile (SOAP). Material and Methods: SOAP questionnaire, a validated tool, was used for data collection. In the first phase, 1521 personnel involved in the exercise, including aircrew as well as ground duty tradesmen completed the SOAP questionnaires twice during the simulated sustained military operation. The subjective ratings were statistically analyzed using the Wilcoxon matched paired test. The two levels of repeated measures being mean SOAP scores on day 2 and that on day 5. In the second phase, to ascertain differences in the subjective ratings of SOAP among different streams of pilots, data were recorded during another simulated sustained operation after 6 months. A total of 140 aircrew responded to the SOAP questionnaire during 6 days of sustained operations. SOAP score was acquired on day 1 and day 6 of the operations in the second phase. Results: A total of 3042 completed SOAP responses were analyzed. There was a significant increase in ratings of the three cardinal dimensions of SOAP among all personnel. The aircrew rated the subjective effects higher than maintenance or administrative support group. Among the aircrew, the fighter pilots rated significantly higher as compared to transport or helicopter aircrew. Conclusion: The study revealed significant changes in the cardinal dimensions of SOAP among the aircrew who were routinely not involved in shift work (especially fighter pilots). Scientifically designed “shift work” may be an effective strategy to mitigate effects of fatigue during sustained operations, hence, needs to be practiced as a routine by combat Air Force units.