Reservations were expressed about various technological features such as the folding wing concept and the possible need to employ six engines (although some airlines regarded them positively) and, in the horizontal double-bubble, the aerodynamic effectiveness of twin fins and the acceptability of tension links down the middle of the passenger cabin.
Major operators of Airbus Industry equipment considered commonality between types to be an important factor.
Some airlines expressed concerns about certification and safety aspects, for example, would a configuration with more than two aisles require wider cross-aisles and wider doors to meet emergency evacuation regulations?
JAL questioned whether more stringent certification requirements should not be introduced for very large aircraft to give higher levels of safety and increased system redundancy.
Span and length considerations
Fig.: 2.6.4 Ref.: HLIA1-CM
Most airlines would like to see overall dimensions no greater than those of the 747-400 in order to minimize problems on the ground. One airline saw no problem with a wider span and possibly with greater length as well, whilst objecting forcefully to the folding wing concept. A number of other airlines did not object to the idea of folding wings.