On the effect of stage length on the efficiency of air transport

Abstract

AbstractIt is generally recognised that fuel can be saved on long haul routes if non-stop flights are broken down into a number of short stages. As fuel costs rise, these savings may eventually become economically attractive to airlines. ‘Staging’ may also play a role in the reduction of aviation’s impact upon climate change. To allow an accurate estimate of the potential benefits, an analytic model has been developed from first principles, with closure provided by data from existing aircraft. The analysis captures the relevant parameters and their influence is quantified. It has been found that significant savings are only available for distances greater than about 5,500km and a stop at the halfway point is either the best, or close to the best, strategy. For the longest routes, optimal staging with existing long range aircraft can give savings of up to 12%. However, if aircraft optimised for the stage lengths are used, this may be increased to up to 28% and, if the floor area per passenger is reduced to the short haul level, a limiting value of about 45% may be possible. The aircraft design passenger number and, provided it is constant, the load factor have little, or no, effect upon the percentage savings. Maximum use of staging on all current routes longer than 5,500km could reduce the total fuel consumed by between 3% and 20%, with a consequent reduction in global fleet annual fuel burn of between 1% and 6%. However, the savings for a given route are reduced as aircraft become more efficient.