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Last year, McKechnie Vehicle Components established (Paper 2000-01-1098) that there were two factors influencing joint integrity between a multilayer fuel tube and the barb design of a plastic quick connector: The relationship between barb O.D. and tube I.D. The type of lining material of the tube and the overall hoop stress the tube applies to the joint after assembly. It was recommended that future work should address the following points if a full understanding of the fuel tube material to barb type is to be achieved: Assess the sealability of different materials onto a common barb type Assess a range of different barb designs to depict the optimum This year the authors have attempted to address the above points. Two conductive liquid fuel tubes of different commercial sizes (American and European) were manufactured in commercial multilayer structures. These had different material inner layers (PA12 and PBT).

Anticipating the need to improve the level of comfort for passengers in future aircraft designs, a study on the cost of providing more space for economy class seating has been conducted. Using an existing aircraft design (B777) as the baseline and British Airways published accounts it was shown that only about three extra economy ticket sales would be necessary to offset the operating cost increase associated with the larger fuselage. Franchising and carriage of cargo in the extra space was also investigated but shown to be uneconomic. The effect of aircraft size was studied by applying the analysis to a larger (MD12) and smaller (B757) aircraft. These investigations showed that provision of extra space is more advantageous for the larger aircraft but still remains economic for the smaller type. The method provides the basis for more detailed analysis in future studies.