Towards an adjustable aircraft seat pan creating comfort for small and tall persons

When designing a comfortable aircraft seat a large variety of occupants must be considered. Also, variation of posture is seen as an important factor for creating comfort, and the question is how to translate that in a seat design. Past studies show that, for a comfortable position in an SUV and sedan seat, most of the pressure (50-60% of the total body weight) should be under the posterior one third of the contact area between seat and human, along with 20% in the middle and 10% in the anterior part. Other studies show that a large contact area between human and seat is preferable. It is not simple to design a seat facilitating variation of posture, creating an ideal pressure distribution and large contact area for a large variation in human sizes. For instance, having short lower legs increases the pressure in the front of the seat and having short or long upper legs might reduce the contact area. To overcome these problems in this project an aircraft seat pan was developed that was able to adjust both the height of the front of the seat pan and the length of the seat pan. The question was if this is technically feasible without adding too much weight. Therefore, a project was started to develop and design a mechanism that could be implemented into an aircraft seat. In this paper the background for the development of this seat is described and an evaluation was done technically to see if further technical improvements are needed and some people used the seat to have a first impression on the users’ opinion. The first impressions are promising, but a lot has to be done also on the usability of the controls and further development is suggested.