Incorporating Lean Six Sigma into an Aviation Technology
M. E. Johnson1, S. I. Dubikovsky2
Purdue University, Department of Aviation Technology, West Lafayette, Indiana, USA
Lean Six Sigma (LSS) is being used in many industries to achieve dramatic performance
improvements in their operations, maintenance, engineering and business processes. Aviation
companies are demanding that graduates possess more problem-solving skills as a requirement for
both employment and success. To be better prepared to succeed in an increasingly competitive
environment, technology undergraduate students are being introduced to the structured problem
identification and problem solving methodology of LSS.
The professors in the aviation technology program are redesigning courses in the curriculum to give
students a solid background in the methodology and techniques leading to a senior-year capstone
project course that uses the LSS process of tollgates. Specifically, the courses address two major Lean
Six Sigma methodologies: DMAIC and DMEDI. DMAIC is a methodology for process or product
improvement. DMEDI is a methodology for process or product design. This paper describes the
purpose of the new courses, their integration into the aviation technology, the new elements in the
courses, and the capstone project.
The expected outcomes are that students will gain knowledge and experience in the engineering
aspects of designing and the maintenance side of aircraft. As mentioned before, some of the graduates
will apply for jobs at major aircraft manufacturers, where the challenge is to fill the gap between the
production floor and the engineering department. In addition to manufacturing liaison positions,
graduates also get jobs in scheduling, tooling design, and even purchasing. To better prepare the
students for these careers, these new courses are designed to teach the students not just to follow
instructions, but to give them a set of tools to truly understand the design or improvement process.
Keywords: Lean Six Sigma, undergraduate, student design project, capstone project, design, product
Aviation companies are demanding that graduates possess more problem-solving skills as a requirement for both
employment and success. To improve the quality of aviation technology graduates, professors in Aviation
Technology at Purdue University are incorporating Lean Six Sigma skills, techniques and methodologies in a
new senior-year capstone project course and in existing courses. This paper describes the Aviation Technology
courses, their integration into the aviation technology curriculum, the new elements in the courses, and the
Six Sigma originated at Motorola in the 1980’s and enjoyed an early start in aerospace companies such as
General Electric and United Technologies. Since that time, Lockheed Martin, Raytheon and many other
aerospace companies have adopted both Six Sigma and Lean methodologies to both drastically reduce defect
rates and cycle times.
While DPMO (defects per million opportunities) is a primary measure in Six Sigma, to focus solely on the
reduction in defect rate may limit the understanding of the power of Six Sigma. The data-driven tollgate
methodology in Six Sigma requires a disciplined approach far beyond reducing DPMO.
Six Sigma has five phases with each phase requiring a tollgate review resulting in one of three outcomes:
continue to the next phase, stop the project, or continue study in current phase. These five phases are: Define,
Measure, Analyze, Improve, and Control. This DMAIC methodology is designed specifically for improvement
of existing processes. There is also a similar six sigma methodology addressing design of new products,
components, or processes. However, the phases of the methodology are slightly different: Define, Measure,
Explore, Develop, and Implement. Both methodologies use many tools which address specific needs during each
of the step of the process.
“Lean” is many times understood to be ‘reducing waste’ or sometimes as the “Toyota Production System”.
While it is true that Shigeo Shingo of Toyota presented seven wastes, he also made many other contributions. A
look at the Toyota Lean principles as presented by Womack and Jones reveals a more holistic picture of Lean
1. Define value from the customer’s perspective.
2. Identify the entire value stream and eliminate waste.
3. Make the value creating steps flow.
4. Provide what the customer wants only when the customer wants it.
5. Pursue perfection.
When looking at this list of Lean principles, one may see that ‘value’ and ‘customer’ are emphasized. Value
creation and understanding of value from the perspective of the customer are paramount in Lean. Lean
techniques have been adopted in aerospace companies for many years. In 1993, the Lean Aerospace Initiative at
the Massachusetts Institute of Technology began to formalize and study the effects of Lean throughout the
aerospace industry . Since that time, Lean has been implemented in manufacturing, design, and business
processes in aerospace companies and other industries.
The approach used in these courses is a Lean Six Sigma approach which combines the data-driven tollgate
project methodology with reducing cycle time and reducing variation . The overlap between Lean and Six
Sigma is significant as they both have the goal of improving performance, as shown in Figure 1. As an example
of the overlap between Lean and Six Sigma, consider just-in-time manufacturing, or JIT. While JIT is used to
reduce cycle time, many processes cannot cope with the reduced batch sizes or inconsistent parts and processes,
and must first undergo a variation reduction effort before implementing JIT. To get consistent quality in smaller
batch sizes, many times a process must first be streamlined and simplified, then the variation reduced. Since
Lean and Six Sigma are strategies that have worked together successfully in aerospace and other industries ,
the students will benefit from exposure to both concepts.
Lean … reduce cycle time by adding
value and reducing waste
Six Sigma … reduce variation using a
data driven structured problem-solving
FIGURE 1. Lean and Six Sigma work together to improve performance
3. AVIATION TECHNOLOGY CURRICULUM CHANGES
The Aviation Technology department has existing courses in the design and analysis of systems, but there are no
courses dedicated solely to Lean and/or Six Sigma. Three courses at the senior level expose students to DMAIC
and DMEDI in a project environment where students must use skills and knowledge acquired throughout their
education to complete a project. The three senior level courses are AT496 - Applied Research Proposal, and
AT497 - Applied Research Project, and AT408 - Advanced Manufacturing Processes, shown in Figure 2. The
students are prepared in aviation technology, mathematics and statistics in other coursework in the curriculum.
AT408 AT496 AT497
Advanced Applied Research Applied Research
Manufacturing Proposal Project
Lean Six Sigma Tools Lean Six Sigma Tools Lean Six Sigma Tools
DMEDI DMAIC DMAIC
Define and Measure Analyze, Improve, Control
FIGURE 2. Three Aviation Technology Courses with Lean Six Sigma
In August 2007, two new courses were added: AT496 for the fall semester, and AT497 for the spring semester.
Specifically, these capstone courses use a proposal and implementation approach anchored in the DMAIC
tollgate methodology. In the fall semester, students must find and propose a project to complete during the spring
semester. Students learn about the DMAIC process and find a process that interests them. The students then form
teams and prepare a proposal for the faculty. The students sometimes select processes not under the direct control
of the instructor. Therefore, the team must solicit both cooperation and advice from the process owners of their
target process. Since students are not accustomed to both finding their own project and gaining cooperation of
others, the team learns new skills in problem-solving such as project selection, team dynamics, and presentations.
This is in addition to learning how to prepare a proposal. After the project is proposed and accepted, the team
implements the project in the spring semester. In the AT497 course, the team must use technical knowledge,
project management, and conflict resolution skills to successfully complete the project.
The projects developed by the students are all concerned with redesigning processes within the laboratories in the
aviation technology department. For instance, ‘check out of tools’ and ‘control equipment inventory’ are two
processes identified for redesign by student teams. The teams must identify the problem, its significance, and a
goal that addresses the problem. For these research proposals, the student teams must not focus on the solution,
but rather identifying the problem, defining the problem in terms of performance parameters and their ‘as-is’
performance levels, then identify the goal or ‘to-be’ level of these parameters. To address the gap between ‘as-is’
and ‘to-be’ performance levels, the team must devise a project plan to be accomplished in the next semester. The
team members must not only agree among themselves, but also convince the process owner (in this case the
other professor whose lab is involved).
AT408 exposes the students to DMEDI methodology. The main idea behind this course is to provide our
students with a set of skills to find jobs in Original Equipment Manufacturer (OEM) in field of aviation such as
Boeing, Pratt&Whitney, Rolls-Royce, etc. A large percentage of AT graduates are hired by OEMs where they
work side-by-side with the engineers. Many of these AT graduates fulfill engineering functions and wear
engineering titles. To be successful, this means the students have to understand how the design process works.
AT 408 is a final senior level course performing advanced materials manufacturing. These projects are designed
to help students better understand engineering fundamentals and technology applications in industry. Successful
project completion also requires communication and planning skills as students acquire the new language of
manufacturing, taking projects from planning to hands-on design and delivery. The students must follow all
stages of the design process, including project cost assessment, establishing timelines and producing process
sheet and work instructions.
Students in AT 408 have developed basic aircraft materials skills from prerequisite coursework within the
curriculum. In this course, students integrate baseline technical skills with larger problem solving skills and
processes involved in design and manufacturing of more complex component parts, including structural joint
design and aircraft components which play a critical role in flight safety in industry. The course is almost
entirely project-based allowing students to perform research and to design products to specific requirements.
4. DMAIC METHODOLOGY
As mentioned above, the DMAIC methodology focuses on improving an existing process or product. These are
mostly “real-life” problems, which need to be solved. The improvement should be scoped such that it can be
completed in approximately three months and be able to sustain this improvement for long period of time. The
methodology consists of five phases: a) Define business opportunities, b) Measure performance, c) Analyze
opportunity, d) Improve performance, and e) Control performance . The AT496 course addresses “define” and
“measure”. During the AT497 course, the student teams analyze and improve the performance of processes. The
most difficult portion of the AT497 project is the control portion where the student teams must not only hand off
the project to the process owner, but also have put in place measures that will sustain the gain in performance.
Because many good process improvements tend to fall back into the ‘old way’ once the improvement team has
moved on to the next project, the control portion must be designed and implemented to maintain the performance
This DMAIC methodology was selected for the AT496 and AT497 courses due to the nature of the projects
being for process improvement, and due to the fact that the DMAIC methodology is used in many aerospace
companies as their preferred method for process improvement. It is very important to note that the AT 496 and
AT497 courses are not courses in DMAIC or Lean or Six Sigma. These two courses are project proposal and
project implementation courses, with those two objectives being the primary objectives. The DMAIC
methodology is being used as one vehicle to proceed through the proposal, implementation, and hand-off stages
in the project. The DMAIC methodology helps students tackle a process improvement project in a structured
manner. During the AT497 course, the student teams use Gantt charts and weekly project reports to communicate
their progress with the instructor and to manage their projects. This is the first year the courses are being offered.
5. DMEDI METHODOLOGY
The DMEDI methodology deals with new product, service or process creation . The first two steps of this
methodology are the same as for DMAIC. This is due to the same need to define business opportunities and
measure inputs and outcomes. However, the other phases are different: Explore options, Develop a new product,
process or service, and Implement the best solution.
This DMEDI methodology was selected for the AT408 course to expose the student to new design of a product,
process or service which will increase their chances of being hired by original equipment manufacturers. The
time has passed when graduates of the Aviation Technology department at Purdue University worked only as
aircraft mechanics. New requirements for maintenance personnel are in demand now by top employers. Not only
do these graduates have to be skilled in aircraft maintenance, there is also an expectation that they have
experience working in teams, preparing and delivering presentations, and problem-solving. In AT408, the
emphasis of the course is not to teach DMEDI, but to teach design and advanced manufacturing processes.
Many companies in the United States, not just in the aerospace industry, are using DMEDI methodology to
design new products or processes. It provides a certain set of tools such as Brain writing, C-Sketch, 6-3-5
Method, Decision (Pugh) Matrix, and others. If the tools are used properly, the design process should bring
optimum results. This is the most important reason why DMEDI was developed and is used in the industry. Not
knowing this methodology would limit the students’ ability when gaining an employment. Through the students’
hands-on projects, the students learn both the DMEDI methodology and how to apply it.
6. EXPECTED OUTCOMES
These changes are in their first year of implementation. The expected outcomes are that students will gain
knowledge and experience in engineering aspects of designing and maintaining aircraft, which will enhance their
future careers in either industry or academia. As mentioned before, most of the graduates will apply for jobs at
major aircraft manufacturers, where the challenge is to fill the gap between the production floor and the
engineering department. In addition to manufacturing liaison positions, the graduates of our program are offered
jobs in scheduling, tooling design, and even purchasing. To better prepare the students for these careers, these
new courses are designed to teach the students not just to follow instructions, but to give them a set of tools to
truly understand the design or improvement process. Exposure to Lean Six Sigma techniques is expected to
benefit the student in completing high quality design and implementation assignments during their senior year,
and will be useful in their future careers.
7. OUR EXPERIENCES
Early feedback from the students is positive. Comments from students vary, but one consistent comment is that
while the work is interesting, it is sometimes difficult to know what to do next to solve the problem. This is to be
expected when students are confronted with open-ended problems that are complex in nature. Some other
comments are that it is difficult to work in teams and to work with other groups both in their class and outside
the classroom. In these new Aviation Technology courses, the students really take their given responsibilities
very seriously and work diligently to provide a solution to the tasks. Prior to this point in their studies, the
students are taught to perform certain duties, but have not yet been given the responsibility of the whole project,
which becomes “their” project. These senior level courses are different in that the projects are the teams’ projects
and that their contributions are crucial to the success of the project.
Another benefit of the courses is that the students are not trying to resolve so called “educational problems”,
which do not always have practical application in the students’ minds. In these three courses, all projects are real
projects as they fulfill the needs of a laboratory, and these projects are implemented by the students. For
example, projects in the AT408 class focused on designing and manufacturing missing components on a
PW4000 turbine engine used as a teaching aid in the Gas Turbine Technology laboratory. The task is very
practical and real. The students realize this and take pride in knowing that many years after they graduate the
components produced by them may still be on the engine. One example of the projects in the AT496 and AT497
classes is a cycle time reduction project to reduce waste in laboratory work. The team identified wastes and their
causes. Transportation waste was addressed, and the team was surprised to find that students each walk over
1900 feet during labs, and that through workplace organization and layout improvements that this distance may
be reduced to only 300 feet. These preliminary results are just one of the performance improvements being
implemented by the team.
8. FUTURE WORK
While design and manufacturing of useable, airworthy parts with timely turnaround is the ideal target in industry,
such expectations are projected to be unrealistic at times given the real life constraints of laboratory timeframes,
limited resources and lack of technical field experience among student groups. In future offerings of these three
courses, the use of the DMAIC and DMEDI methodologies will be refined. A next logical step of these project
courses is to extend the nature of the problems by collaborating with industry to work on current problems in
their products or processes. In addition, these projects may be a seed that encourages students to enter graduate
school and focus their research in these areas. The instructors are considering implementing problem based
learning methods in the course work and more consistent performance expectations and team reporting methods
across the senior year curriculum to further enhance the student learning experience.
 J. P. Womack, D. T. Jones, “Beyond Toyota: How to Root Out Waste and Pursue Perfection”, Harvard
Business Review, 74, 5, 140-158 (Sep/Oct 1996).
 MIT, Lean Aircraft Initiative, http://lean.mit.edu. Accessed October 15, 2007.
 M. George, Lean Six Sigma: Combining Six Sigma Quality With Lean Speed, Boston: McGraw-Hill (2002).
 H. S. Gitlow, D. M. Levine, Six Sigma for Green Belts and Champions, Pearson, Prentice Hall: Upper Saddle
River, NJ (2005).
 G. Brue, Design for Six Sigma, Boston: McGraw-Hill (2003).