Aircraft Seat Research Articles

Objective and subjective evaluation of a new airplane seat with an optimally pre-shaped foam support.

Aircraft seat manufacturers are making efforts to reduce seat weight while continuously increasing seating comfort. To verify if seats with an optimally pre-shaped foam support could improve seating comfort while reducing seat weight. The optimally pre-shaped surface was obtained from a synthesis of 95% of individually optimized compressed seat pan surfaces of a target population. Two new seats were proposed with two different cushions, one slightly softer and the other harder. Nineteen differently sized volunteers tested the two new seats and an existing seat randomly. After an assessment of initial discomfort, participants were instructed to watch a TV series for 50 minutes. A same questionnaire was used to assess both initial and longer-term discomfort. Contact forces and pressure distribution were analysed as well in-chair movements (ICM) during sitting. The two new seats exhibited lower shear, lower peak pressure and larger contact area on the seat pan as well lower number of ICM during the 50 minutes sitting. They also had lower initial overall discomfort, though significant differences between the seats were not found after the long sitting. Properly pre-shaped surface could be used as foam support to reduce the amount of foam while reducing seating discomfort.

Design optimization of a business aircraft seat considering static and dynamic certification loading and manufacturability

A conceptual design for a lightweight business aircraft seat was developed using topology optimization in a 2-stage approach to consider both the static and dynamic certification test requirements of the Canadian Aviation Regulations (CARs) Section 525.561 and 525.562, respectively. Preliminary optimization was performed using static load requirements, and the interpretation of the optimization results was done considering key manufacturability metrics to reduce the cost of manufacturing components when using traditional subtractive manufacturing methods. A series of explicit dynamic models was run to predict the behavior of the seat during 14g and 16g certification tests and to estimate the maximum loads which the anthropomorphic test device (ATD) applies to the seat structure. Peak seatbelt loads were estimated at 9060 N and 8955 N for the left and right sides, respectively, and the asymmetry of the loads can be attributed to the 10° yaw of the aircraft required by the 16g certification test. Topology optimization was used to refine the design at the component level and further reduce weight using the loads determined in the dynamic modeling. The final conceptual design was 32% lighter when compared with the baseline structural components, and key manufacturability cost metrics were reduced by 24%.

Airbag models for aircraft passenger seats

Two analytical models are presented for an airbag installed as an aircraft seat cushion to reduce shock to passengers during an emergency. In the first model, an airbag is modelled as a rigid cylinder, while in the second model, initial deformed shapes and volume changes of an airbag after crash are considered. In numerical simulations, effects of orifice contraction coefficient, exhaust diameter ratio and rupture pressure on the inner pressure of the airbag, and acceleration and displacement of the falling body are clarified for the two models by dropping a falling mass against a pre-inflated test airbag equipped with an exhaust orifice. Furthermore, the numerical results are compared with experimental results.

The effect of aircraft seat pitch on comfort

This study explores the relationship between seat pitch and comfort, and the influencing factors, like space experience and anthropometric measurements. Two hundred ninety-four participants experienced economy class seats in a Boeing 737 with 28-inch, 30-inch, 32-inch and 34-inch seat pitches. Anthropometric measurements of the participants were measured. Participants completed a questionnaire on comfort (10-scale), discomfort (CP-50) and space experience and the results were analysed using SPSS 25. This study showed a significant relationship between seat pitch and comfort as well as discomfort. Additionally, it was found that the mean rank of discomfort of each pitch size for the middle seat was higher than the window and aisle seat, though seat pitch did affect the (dis)comfort more compared with seat location. It was also found that anthropometric sizes significantly affect the (dis)comfort on smaller pitch sizes, and all space experience questions had a correlation to the pitch sizes.

Aircraft Passenger Comfort Based on Muscle Activation and Perceived Discomfort During Long Flights.

OBJECTIVE: The purpose of this study was to investigate the comfort of aircraft passengers during long flights and to determine the effects of the seatback angle and the seat pitch on passengers' upper body muscles (neck, shoulder, and lower back) and subjective comfort.METHODS: All subjects sat on an aircraft seat for 2 h with different levels of seatback angle and seat pitch. Subjective discomfort scores and root mean square (RMS) and mean power frequency (MPF) values were used to evaluate muscle fatigue, and all data were calculated for every 15-min interval.RESULTS: Significant increases of MPF for all three muscles were found at 30 min, along with significant increases in the perceived levels of discomfort (PLD) over 2 h. Besides, a 120° seatback angle and a 34˝ seat pitch resulted in lower PLD values for the lower back and hip areas than smaller ones (significant difference).DISCUSSION: It took around 30 min before pronounced discomfort in the upper body regions occurred during flight. The larger parameters of seatback angle and seat pitch may significantly contribute to the easing of subjective discomfort. Moreover, a decrease in MPF coupled with a concomitant increase in RMS does not appear to be a reliable indicator of discomfort rate. The need for further development of discomfort indicators which are more directly related to muscular activation is recognized.Pei H, Yu S, Ding M, Bai Z. Aircraft passenger comfort based on muscle activation and perceived discomfort during long flights. Aerosp Med Hum Perform. 2020; 91(5):416-421.

Factorial Study on Seated Aircraft Passengers’ Body Heat Harvesting

The increased electrical power demand for aircraft subsystems drives the search for a new alternative onboard power source. One of the solutions that have been proposed is the heat energy harvesting of the aircraft passengers’ body. Taking advantage of the Seebeck effect phenomenon, the dissipated heat from seated passengers’ body can be converted into useful electrical power using a thermoelectric generator. The main objective of this study is to establish whether the performance of such heat harvesting system is highly dependent on the passengers’ body features and cabin environmental temperature. An experiment with 10 volunteers using a mock-up aircraft passenger cabin setup is conducted and the temperature readings when they are seated on the aircraft seat is recorded through installed thermal sensors. The collected data is then analyzed using Analysis of Variance (ANOVA) method to find the factorial contribution of volunteers’ age, weight, height and gender, plus the ambient temperature, on the performance of the heat harvesting system. In this case, potential performance of such energy harvesting is measured by the maximum temperature differential that can be possibly obtained. Based on ANOVA results, the passengers’ weight, height, age and gender do not have a significant effect on the temperature differential. This can be taken to imply that the heat harvesting performance is not highly dependent on the passengers’ characteristics. In contrast, ambient temperature is found to be influential, meaning that operational performance of such heat harvesting mechanism can be controlled through appropriate setting of the cabin environmental temperature.

Design and development of a motorized aircraft seat to substitute aisle wheelchairs

Purpose The solution described in this paper allows wheelchair users with reduced mobility or physical disabilities to move independently throughout an aircraft and to board and disembark autonomously. Materials and methods A motorized aircraft seat was developed to substitute current aircraft aisle wheelchairs. The real-scale functional prototype was evaluated in a focus group. The results show that the proposed solution is considered superior to current solutions in nine of twenty requirements and neutral in one of them. There was low agreement among the focus group participants in ten requirements, even though the focus group discussion brought interesting reflections, including positive feedback, critics, and suggestions for further research and development in the field. Results The design concept consists of a motorized wheelchair that becomes the seat of the aircraft when anchored on a docking platform attached to the aircraft fuselage via a seat track. The manoeuvring is allowed by a rotating mechanism, which solves a critical function that is to enable wheelchair manoeuvring in the narrow aisles of aircraft. A parking assistant system aids the control of the motorized wheelchair. Conclusions The main benefits of this solution are to reduce seat transfers during the flight experience and to provide more autonomy and comfort for passengers during flights. IMPLICATIONS FOR REHABILITATION A motorized aircraft seat was developed to replace traditional aircraft aisle wheelchairs. A real-scale functional prototype was built, tested in an aircraft mockup, and evaluated in a focus group. The main benefits of the proposed solution are to reduce the number of chair transfers during the flight experience and to provide more autonomy for passengers. Additional benefits are to allow the passengers to experience less physical and emotional stresses, to enter the aircraft corridor looking ahead, and to sit in any aisle position in the aircraft.

Multi-objective Goal Programming for Low Altitude Seat Ejections with Fuzzy Logic–Based Decision-making

Aircraft seat ejection systems are essential lifesaving equipment for pilots. Although seat ejections have improved in terms of success rates over the past few decades, ejections at low altitudes (below 150 m) remain a serious concern. These are time critical events and demand optimal process parameters to improve the odds of successful ejection due to the lack of lifesaving height and various other factors. The study optimizes impulse applied and the angle of ejection of the pilot with a novel Multi-Objective optimization approach to minimize Dynamic Response Index (DRI, used to quantify spinal injury) and to maximize the ejection height. The Pareto-optimal solutions are obtained thereof for different scenarios of aircraft flight. A fuzzy logic system is used to handle the uncertainties due to the objective functions under different ejection scenarios of the aircraft; it is used as a decision-maker to choose the initial parameters for goal programming based on the severity of the ejection scenarios. The results were compared with ideal solutions obtained from Pareto fronts using the same fuzzy logic system as decision-maker. The goal programming gave similar results at a quicker time making it advantageous over the conventional “generate first choose later” methods.

Effects of aircraft seat pitch on interface pressure and passenger discomfort

Seat pitch, defined as the distance from a point on the back of one seat to the same point on the seat in front, is one of the most important factors influencing aircraft seating comfort. This study assessed the influence of different airline seat pitches on subjective ratings of discomfort and body-seat interface contact pressures. This was a laboratory within-subjects study using an aircraft interior mock up to vary seat pitch. Twelve participants completed 1 h of sitting in each of five different seat pitches (28inches, 30inches, 32inches, 34inches, and 36inches). Interface pressure mats measured seat and backrest pressure distribution, subjective rating scales were used to measure overall and local body region discomfort. The results showed that overall body and local body region discomfort ratings tend to be lower when the seat pitch increased from 28 inches to 36 inches (p < 0.05). For pressure variables, the upper back average contact area, upper/lower back average contact pressure, upper/lower back average peak contact pressure, right buttock average contact area, left/right thigh buttock average peak contact pressure, and left buttock average peak contact pressure were significantly affected by seat pitch(p < 0.05). Separate analyses support that seat pitch was more strongly correlated with backrest interface pressure than with seat pan pressure. In conclusion, seat pitch was found to be an important factor associated with body-seat contact pressure and discomfort ratings.

Analysis and modeling of human seat interaction with a focus on the upper body and backrest using biomechanics and contact mechanics.

This paper outlines a method to study the interaction between the human body and the aircraft seat concerning the seat comfort. Firstly, the human body is modeled based on biomechanics and divided into a number of body segments connected by joints according to human anatomy. The angles between the body segments are obtained by curve fitting of the existing biomechanical research data. The contact forces between the human body and the seat are modeled using pairs of bi-lateral point forces. These forces are calculated and located through the analysis of the center of gravity of each body segment and average muscular structure of the human body. The geometry of the human and the seat is obtained from a 3D scan model or a CAD model. Secondly, the pressure distribution between the human body and the seat is modeled and calculated using the contact stress theory. The results of the two parts are combined to analyze the comfortability in relation to different postures, backrest recline angles and changing in shape and material. Simulations were performed and they are compared with experimental measurement and various FEM studies for validation. It is found that accuracy of this method is comparable with most FEM calculation. This method provides a new direction in cushion conform research. It is faster and convenient to use comparing to the FEM, and the result is reliable.

A model-based approach for the analysis of aircraft seating comfort.

Aircraft seating comfort has a significant impact on passenger on-board experience. Its assessment requires the adoption of well-designed strategies for data collection as well as appropriate data analysis methods in order to obtain accurate and reliable results. This paper focuses on the assessment of aircraft seating comfort based on subjective comfort responses collected during laboratory experiments and taking into account seat features and passenger characteristics. The subjective comfort evaluations have been analyzed using a model-based approach to investigate the relationship between overall seating comfort and specific seat/user characteristics. The results show that the overall seating comfort perception is significantly influenced by the thickness of the seat pan, the backrest position (upright or reclined), the age of the passenger and the passenger perception of being comfortably supported at the lumbar region. The adopted model-based approach allows the analysis of subjective seating comfort data taking into account their ordinal nature as well as the dependency between evaluations provided by the same subject.

Posture, movement, and aircraft passengers: An investigation into factors influencing in-flight discomfort.

Aircraft passengers' physical activity levels are often limited during flight for extended periods of time, which can have serious impact on health, comfort, and passenger experience. However, several factors, such as limited personal space and social factors, can make movement difficult. The study aimed to identify participant behaviour and postures during medium to long-haul flights and their effect on location and severity of physical discomfort. This work investigated how aircraft passengers' comfort ratings changed over time and explored the association between postures and comfort ratings during flight. The study also explored the association between performing in-flight exercises and factors limiting participants' abilities to complete these exercises. Twenty-nine participants sat in an aircraft simulated cabin for 180 minutes and periodically performed in-seat exercises. They also completed a questionnaire providing data on demographic information, self-reported discomfort scores for multiple areas of the body, which types of exercises participants performed, and qualitative comments about discomfort. Self-reported comfort ratings were measured at 20 min intervals and posture identification was conducted by analysing the video recordings. Six postures were identified, and it was observed that individual participants changed posture at least once and up to nine times during the three-hour period. Body part areas with the highest reported scores of discomfort ratings were: back of the neck, back-left shoulder, back-right shoulder, back-left buttock, and lower back. Participants reported that they had difficulty in performing recommended in-flight exercises due to limited space. Limited space in aircraft seating restricts passenger movement. Some body areas are more prone to discomfort.

Halogen free flame retardant finishing of wool and wool rich fabrics for aircraft seats

Wool and wool/nylon blended yarns were knitted and treated by a phosphorus sulphur based agent by padding. The flammability hazard was evaluated considering parameters such as; the spread of flame, heat release and smoke emission. The flame spread of fabrics was measured according to the FAR/CS 25.853 12 Second Vertical Bunsen Burner test procedure. Regardless of the blend ratio, the fabrics treated by the flame retardant (90% add-on) could comply with the vertical flammability requirements for aircraft materials. Important flammability parameters such as heat release rate and peak heat release rate ware measured by the cone calorimeter. The FR treatment of fabrics was found to be effective in reducing heat release and thus risks associated with fire. The smoke generated by the materials during flaming combustion was evaluated by both cone calorimeter and NBS smoke density chamber.

Risk of Passenger Injuries in the Virtual Certification Tests of an Aircraft Seat Unit

Risk of Passenger Injuries in the Virtual Certification Tests of an Aircraft Seat Unit

Air Travel for People Who Use Wheelchairs: Survey Results

To assess the perceptions of air travel for people who use wheelchairs: Topics included: attitude of airport and airline staff, ticketing, boarding the aircraft, sitting on the aircraft seat, and stowage of a wheelchair.

Development of a Head Injury Criteria-Compliant Aircraft Seat by Design of Experiments

This paper deals with the redesign of an aircraft passenger seat, placed at the first seat row, which was not compliant with Federal Aviation Regulations FAR 25.562 “Emergency landing dynamic conditions” regulation (due to a high value for the Head Injury Criterion (HIC)) and related guidelines. Starting from an accurate analysis of some results obtained via an experimental seat sled test, a numerical procedure was developed in order to improve the passenger safety with respect to head injury. Specifically, the proposed numerical procedure, using the advantages of a Finite Element (FE) model and a Design of Experiment (DoE) approach for simulation modeling, was aimed at identifying a new design solution to avoid the impact between the passenger’s head and the bulkhead. The redesign of the passenger seat was validated against an experimental test carried out at Geven S.p.A. Company by demonstrating, consequently, the compliance of the modified seat-belt system with the regulations.

Estimating the Cost of Biofuel Use to Mitigate International Air Transport Emissions: A Case Study in Palau and Seychelles

International air transport is one of the fast-growing sources of CO2 emissions. However, it has always been omitted from the international emission mitigation pledges. The delayed mitigation process in this area may slow down the process of global CO2 emission control. In this article, we evaluated the potential to realize the emission mitigation targets in air transport through biofuel and estimated the corresponding cost. The emission from international air transport of Palau and Seychelles was taken as the example. Then, the emission caused by each airline to these two islands was calculated by the distance-based method, with information of the travelers’ arrival data, fuel consumption of different aircraft types, routes, and aircraft seat data. Future scenarios with and without commitment to CO2 mitigation targets were predicted to evaluate the emission difference. Then, we estimated the amount of biofuel required to fill the emission gap, and the corresponding cost based on the future biofuel price prediction. The results show that distance is the determining factor of international air transport emission per capita. The component of origin can decrease the aggregated emission per capita to small island destinations by 0.5–2%. The accumulated emission gaps are 3.15 Mt and 9 Mt for Palau and Seychelles, which indicates that 7.64 and 19.34 Mb of biofuel are needed for emission mitigation, respectively. The corresponding costs are $27–163 million and $72–424 million per year.

Neck posture and muscle activity in a reclined business class aircraft seat watching IFE with and without head support

The purpose of this study is to research if a headrest benefits the comfort of the passenger and lowers muscle activity in the neck when sitting in a reclined (slouched) posture while watching in flight entertainment (IFE) in an aircraft business class seat.No significant differences in muscle activity in the musculus sternocleidomastoid and musculus trapezius pars descendant were found between the conditions with headrest and without headrest. A significant difference in expected comfort rating was found. Subjects indicated they expect to experience more comfort with a headrest when watching IFE for a duration of two movies during a long-haul flight. This study also found a significant difference in posture. In the condition without headrest the head was more upright compared to the condition with headrest.The lack of significant difference in muscle activity and the significant difference in posture may indicate that humans tend to look for a head position that is neutral, in the sense of minimal muscle effort. This study shows that the use of a headrest may benefit the comfort experience of the passenger during flight. However, further research is necessary on the design of the headrest and the long-term effects of head support on comfort, discomfort, muscle activity and fatigue for watching IFE in a slouched posture.

Analysis of Integrated Fuselage Composite Seat for Small Aircraft in Crashworthiness Applications

The research paper is addressed to develop and validate an aircraft seat cushion to be used for the passenger seat directly integrated in the fuselage. For very light aircraft, these systems result to be a good choice in terms of weight reduction and space optimization, but can represent a challenging problem for crashworthiness design and a key energy-absorbing function for human protection from injuries so to improve the level of the safety. The first issue was dedicated to investigate the mechanical properties of four commercial foams, diffused in different industrial applications, which present nonlinear and time-dependent viscoelastic behavior, and finally to determine whether typical seat cushion materials are rate sensitive or not. Then, numerical simulations were validated with measurements to simulate the mechanical properties of foams and to evaluate the contact pressures, stress distribution, and the dependence of stress on the strain rate in order to provide adequate levels of both comfort and energy absorption.

Detección de fugas de vacío con ultrasonido en moldes para fabricación de asientos de avión en planta safran seats shells

The Application of ultrasound prototype is described to detect vacuum leaks in molds used in the manufacturing of aircraft seats, at the Safran Seats Shells Plant. A prototype has been designed and manufactured by the Academic Group(CA) named "Predictive Maintenance Systems", UTCH-CA-13”, belonging to the Technological University of Chihuahua(UTCH), in the career of Industrial Maintenance. Safran Company contacted the UTCH Industrial Maintenance career, requiring support on leaking in molds. The methodology followed by the Academic Group consists of a visit to the plant in order to visualize the leaking failures on molds , then developed of a hermetic system in the UTCH simulating the mold test conditions, initial tests for the detection of vacuum leaks starts in the laboratory using an ultrasound prototype and hermetic system tester. In the production floor at Safran plant, leakage tests were carried out on the molds using the prototype. Final results were the successful detection of mold vacuum leakage considered as critical issue in the production of the Safran plant. This detection contributes to shorten the mold repair time also improving the quality product and avoid the use of defective tooling.