Redefining the 757 replacement: Requirement for the 225/5000 Sector, Part 2.

By Bjorn Fehrm

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01 March 2015, c. Leeham Co: In the first part of the article series around the need for a more capable solution for 180-240 seats and 5,000 nautical miles, we went through the derivative aircraft that Boeing could field as competitors to Airbus A321LR and showed why none of them are effective. We also established the market requirements and the likely market size for aircraft that shall cover this segment and the required efficiency and overall cost improvement needed.

We will now look at different solutions to the requirements, first by analyzing what key characteristics does single and dual aisle aircraft have and what consequences will they have for the aircraft's efficiency parameters like weight, size and drag. Once we have these characteristics we can design adapted aircraft types and calculate their economics such as fuel costs and other costs and we can also establish their operational ground handling times and thereby the consequences single or dual aisle will have on the aircraft utilization.

Having developed and presented these facts it will be possible to forecast what will be the most likely results of Boeing's New Airplane Study, NAS that we presented 2 November last year. Boeing now uses the name, Middle of the Market (MOM) in place of the NAS.


Our second article shows:

  • Drag and weight per seat for today’s short and mid-range aircraft vary significantly between single and dual aisle aircraft
  • There is a strong correlation between aircraft wetted area and aircraft weight.
  • Dual aisle designs in the 180-240 seat segment will have to be highly optimized to be able to compete with single aisle, if at all.

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