The MEA Evolution in Commercial Aircraft and the Consequences for Initial Aircraft Design

Resumé

An important objective in commercial aircraft design is to develop a ’greener’ aircraft. This objective poses many challenges in many fields of aircraft design. The push towards a more environment friendly, efficient and cost effective design has recognized the ‘MEA (more-electric aircraft)’ as a means to contribute towards realizing this goal. The more-electric aircraft can be thought of as an evolutionary concept where non-electrically powered systems and components are gradually replaced by competent electrical systems and components thus leading to an ‘all-electric aircraft’. This paper presents a critical review of a subset of commercial aircraft in terms of the secondary power systems, to form the trends and observe how the importance of electrical power in aircraft operation, has changed over the years. It presents electric load profiles for some conventional aircraft and discusses the parameters that affect the sizing of electrical power sources. It also highlights step changes in technology which had a significant effect on the sizing of power sources. The purpose of the review is to inform and improve the secondary power systems design at the early aircraft design stage, by developing a new methodology. The results presented here firstly show that the total electrical load in aircraft has increased steadily in the conventional configurations and show that there is a rapid increase in the MEA concepts and designs. It also reviews potential reasons for key characteristics identified in the analysis. Moreover, the review reaches the conclusion that an estimate of the generator rating based on conceptual parameters such as the aircraft mass, aircraft service entry year amongst others is not adequate and that a more robust methodology is needed to aid the design process.