1. Sustainable Aviation: Staged Airliner
Service
Individual Project Final Report
Buvanarajahn Rajendra Kumar
7670600
22 April 2013
Project Supervisor: Dr. Peter Hollingsworth

2. SUSTAINABLE AVIATION: STAGED AIRLINER SERVICE
April 22,
2013
ii
Acknowledgements
I would like to acknowledge my supervisor Dr. Peter Hollingsworth for his much appreciated
guidance and input in the completion of this dissertation. Additionally I would like to extend my
gratitude to my course mates and housemates whose moral support provided a driving force in the
effort to complete this through the long days and late nights. Finally and chiefly, I would like to thank
God.
Dedication
To
My Dad, whose character and principles and values provide a much needed aspiration in my quest to
become a man.
My Mom, whose love, nurture and support provided a light in the darkest of nights and comfort in
the gravest of situations even in absence.
My brothers.
May this serve as a symbol of my appreciation and gratitude.

3. April 22,
2013
SUSTAINABLE AVIATION: STAGED AIRLINER SERVICE
iii
Summary
The rising awareness regarding environmental issues coupled with the soaring prices and
uncertainties surrounding the availability of non-renewable resources, specifically petroleum has
bred the need for an urgent and immediate response in order to arrest these issues before it
escalates to an alarming level. This has spurred governments and industry authorities into action
with the drafting and implementation of various directives and regulations aimed at directing the
industry on a more sustainable direction. Sustainable Aviation has consequently become a chief
aspiration of the industry especially against the backdrop of huge forecasted growth in air travel.
While, technological advancements have been pivotal in achieving this in the past, it appears to have
reached its zenith, turning thoughts towards harvesting benefits from more efficient operations.
To this end Green proposed the concept of a Staged Airliner Service which operates long haul routes
in multiple stages not more than 6,000 km each with the aim of saving fuel which is enabled by the
lighter weight of medium ranged aircraft. This was subsequently analysed by various authors who
presented the following:
1. Nangia suggest a 103% fuel saving, sizably correcting the initial 40% savings estimated by
Green when conducting a 15,000 km journey in three 5,000 km stages using a hypothetical
490 seat aircraft which Nangia attributes to Greens omission of reserve fuel required for the
journey.
2. Hahn criticises the analytical method adopted by the former authors promoting instead a
numerical optimisation analyses, arguing that this would be less susceptible to scarcity of
statistical data which leads to a lever of over generalisation in the former study. He further
proposes that the benefit of staging is significantly diminished with an optimised medium
ranged aircraft performing the staged operation merely offering a 29% savings in fuel.
Due to the domination of previous analysis being on the environmental performance concept
revolved around an analysis of hypothetical and optimised aircraft with no consideration of the
commercial aspects, this study was aimed at analysing the current capability of the industry to
perform this concept. This was conducted by analysing the current fleet of aircraft over 11 popular
long haul routes with the aim of quantifying its environmental and economic performance. These
yielded the following conclusions:
1. The concept does offer fuel savings ranging between 30-45% when operated using a
dedicated medium range aircraft and about 12-20% when operating using an intermediate

4. SUSTAINABLE AVIATION: STAGED AIRLINER SERVICE
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2013
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range aircraft over current operations. The benefits of staging however appear to diminish
when the staging concept is conducted by a long range aircraft due to its weight penalty.
2. The effect of the location of the intermediate stages was also identified to have an impact
on the fuel consumed over the entire journey. A stage at a location which does not
correspond with the optimal stage length results in a fuel penalty associated with the bigger
impact of the take-off and climb phases of flight when located at a shorter stage length.
3. It was also revealed that even with its decreased passenger capacity, staging using the
smaller aircraft offer better productivity due to the fuel savings achieved.
4. The economic analysis however painted a different picture for the staged concept revealing
that it did not make as much profits as the current operation due to the limited revenue
achieved by the smaller aircraft used. The profitability of the staged concept did however
appear to increase with ranged and the intermediate range aircraft did offer better
profitability at ranges above 13,000 km.
5. A sensitivity analysis of the concepts profitability suggested that as fuel price increases to
dominate the operating cost, the profits of a staged service increased however yet again
better profits were only observed at ranges above about 9,500 km.
Based on these conclusions, it was finally recommended that a study of the mechanical and
structural implications be conducted along with an analysis of how the growing demand in air travel
will affect the frequency of flights if this concept was implemented and if current ATC infrastructure
was capable of meeting this demand. It was also suggested that the idea of a high capacity medium
range aircraft be explored as it could potentially offer the benefits of decreased fuel burn when
employed on the staged service without the associated revenue limitations.