An investigation of the changing commercial airline passenger anthropometry and its effects on aircraft safety and performance

At first glance, anthropometry and aviation would appear to be unrelated to one another; however, an important relationship exists between them. Aircraft are vehicles that are primarily designed to transport people across long distances, and new aircraft types with enhanced design features are continually being developed, built then entering the aviation market for global airline service. These enhancements to human–machine interfaces ensure continued safety and efficiency, improve performance and prolong the life cycle of components. However, they often do not consider the effect of the changing anthropometric characteristics of the passenger. The media and the medical literature have identified increasing global trends in the average weight and height of passengers, as well as other anthropometrical and biometrical measures. However, the majority of these studies have been limited to exploring the ramifications primarily from the perspective of passengers’ experience.<br><br>This thesis is the first to explore the explicit relationship between commercial passengers’ anthropometry and aircraft safety, design and performance. It highlights the importance of considering passengers’ anthropometric characteristics from a holistic<br>perspective, and it identifies gaps for future research. A thorough search of the available literature shows that this topic has received little attention, thereby demonstrating the need for this research. Most literature to date has revealed that there is limited knowledge regarding the ramifications of changes in passengers’ anthropometry. The two main areas of focus of this research are aircraft performance and aircraft safety.<br><br>Aircraft Performance<br><br>All aircraft are designed to ensure optimal performance during flight, with key flight characteristics interacting and changing depending on the aircraft’s weight. However, the correct estimation of the passenger component of that weight is often overlooked when compared with the weight of freight or fuel. Passenger weight is typically set to a predetermined value by aviation regulators; therefore, it does not reflect the true weight of the passengers onboard. In some cases, the standard weights issued by the regulator are out of date and do not reflect current society trends in obesity. Hence, the research component that addresses aircraft performance explores the effect of passenger weight attributes and obesity on several aircraft performance characteristics.<br><br>The numerical performance analysis uses spreadsheets to calculate the various performance objectives related to specific phases in the flight. The performance literature shows that similar methods have been used to analyse data, predominantly for studies regarding aircraft flight attributes. The key benefit of spreadsheets is that they allow changes to be made to initial base parameters such as passenger weight, aircraft data and initial conditions. <br><br>It was concluded that Western countries with a higher prevalence of obesity and lower standard passenger weights might overestimate performance characteristics such as fuel usage, range, landing and take-off performance. Similarly, countries (predominantly African) with lower obesity prevalence underestimate these performance characteristics because they<br>rely on standard weights from the Federal Aviation Administration, European Aviation Safety Authority and Civil Aviation Authority United Kingdom. Overall performance characteristics for any aircraft type considered in this study will be significantly affected if existing obesity growth forecasts for the next few decades are proven to be accurate. This justifies the need for more accurate regulations and improved flight operational procedures.<br><br>Safety—Emergency Egress<br><br>The design of commercial passenger aircraft must take into consideration the certification requirement that all occupants should be able to evacuate from the cabin within 90 seconds in an emergency. Manufacturers are required to demonstrate compliance with this regulatory requirement using the aircraft to be certified. There is a significant risk of injury to participants when conducting evacuation tests. To determine whether passengers can evacuate safely from the aircraft within 90 seconds, manufacturers may use computer-aided simulations to mitigate risks to participants. This has an added benefit of allowing<br>customisation of the profiles of the individual models used.<br><br>The research component in this study involved simulations using two aircraft types: narrow-body (180 seats) and wide-body (399 seats) aircraft. Both aircraft are modelled using the multi-application egress simulation software package Pathfinder. Multiple scenarios are explored and consist of different levels of obesity prevalence ranging from the control parameter of 55% to higher levels of obesity prevalence that mirror obesity growth forecasts. These scenarios form three situations in which different body mass index (BMI) groups have greater prevalence in society: overweight (2540).<br><br>A total of 98 different anthropometric profiles based on age, gender and BMI were created. Data from the National Health and Nutrition Examination Survey were used for the model in this study. A total of 40 repeated simulations were conducted for each scenario. The results showed that when obesity prevalence increases, the evacuation time of both aircraft types also increases. Increasing overall obesity by just 5% can lead to an increase in the egress time of approximately two seconds for the wide-body aircraft scenario. Further, regression analysis for both aircraft demonstrated that the variables of BMI and distance to<br>exit have strong statistical significance for overall evacuation time.<br><br>A sensitivity study was conducted for delay time, which represents the sit-to-stand time of the occupant. This study was needed because Pathfinder could not allocate delay times to individual profiles, but only to the overall occupant population. The control scenario formed the basis of this study, and the control delay time standard deviation was used as a factor to change the delay time. The results showed that the delay time did not affect the egress time, except for the highest delay time scenario of six standard deviations above the control time. A bus emergency egress exercise was conducted in August 2018 to validate the<br>model. This exercise involved conducting several evacuations from a bus and then replicating the trials in Pathfinder. The results were consistent between the simulations and the experimental exercise and showed that the model has an uncertainty interval of −4.5% to 6.5%.