777-300ER Derivative Airframe Design
Case Study by Skip Reedy
Early and under budget are not typical for an airplane program. Just-on-time and massive overtime are normal. Scope is fixed. A derivative airplane is a new airplane derived from an existing airplane. More than 50% of the airframe was redesigned.
This started as part of a typical 2 to 3 year airplane program. It was also the company’s first large-scale, multi-project, shared resource implementation of Critical Chain Project Management.
Critical Chain Project Management
Critical Chain Project Management (CCPM) is a method of managing any kind of project by focusing on completing tasks (and the project) quickly. It provides exceptional current status so delays and problems can be resolved and mitigated early.
The project consisted of:
- 1,000 engineers and drafters
- 10,000 engineering drawings (2 weeks to 18 months duration)
- Design, analysis, new technology, part and tool designs, & manufacturing plans
- Unusually aggressive schedule
- Tight budget $500,000,000
- Unchangeable deadline
- Each drawing had a committed due date
- Earned Value (EV) and Lean were required
The excruciating challenge was getting the Lead engineers to use Critical Chain Project Management (CCPM). They knew how to design an airplane. They didn’t need a “method.”
Lead engineers often committed to unrealistic and infeasible schedules before they completed their assessment of the project work statements or made plans. Because of …
Normal Project Problems
- Can’t predict due dates in their multitasking environment
- Schedule performance has been poor
- Can’t predict drawing release performance
- Long lead times
- Too many changes
- Suppliers unhappy with receiving drawings late
- High costs
- Chaos, pressure and firefighting are considered inescapable in projects
- Every program has tried something new. None of them change anything, so why bother?
There were 30 unique cross-functional sub-teams/resource pools with dozens to hundreds of people on each team. Each team created 75 to 3000 drawings.Drawing complexity could require 2 weeks, 6 weeks or 18 months.
Design work started “on-time” whether or not the necessary structural stress load inputs were complete. This led to a double negative: designs had to be reworked when the “real” loads came out and the system was struggling with unnecessary work in process.
- Pushing more work into the system than the system can handle
- Allowing and even encouraging multi-tasking
- Rewarding and punishing on the basis of meeting intermediary milestones regardless of the impact on our effective capacity
- Trimming excess capacity without understanding the impact
- Priorities are flexible
- Project schedules are compressed and expected to be met
- Resources are assigned based on task urgency, not project status
- Significant overtime is required
The Breakfast Club
Getting people to believe that CCPM works was initially difficult.
Experienced Leads hoarded the best people.
The quality of work life is poor for the workforce (a common expectation /problem).
People don’t take CCPM seriously unless you turn on the metrics.
Managers claimed that the CCPM reports were simply depicting the project status incorrectly. “Things are a lot better than they appear. They will be better soon.”
But they didn’t get better! They got worse.
Those who didn’t believe that CCPM works had no end of troubles. In other words, things were “normal”, as in an airplane program.
After six months, we were two months behind. The Chief Engineer required the Leads and managers to work 12 hour days, 7 days per week and attend a status meeting every morning at 6 AM, Sundays at 7 AM. Now it felt even more like an airplane program.
This became known as the Breakfast Club. The Chief put the burden of proof on the teams. “Let the data tell us when we are healthy. Until then, act as if the project is in trouble.”
Behaviors within the teams changed quickly.
Those who thought CCPM would work, had no problem with it.
Inexperienced Leads using CCPM ended up doing as well as the experienced Leads that resisted it.
Breakfast was finally served when we were on schedule.
At first, the always-overloaded Stress Analysts refused to put their work in the Critical Chain plans. The development of structural loads is and always will be on the Critical Chain. We chose to exempt them from the CCPM networks under the belief that they already understood their role and were working on the highest priority tasks.
System Constraint (The most heavily loaded resource)
Then Stress found out that they were the system constraint. That gave them a new insight. The constraint determines the system output. If they are slowed down, the system is slowed down. If the constraint goes faster, the system goes faster. They could get more done, and the system would be more productive.
Leads typically dumped large batches of late drawings on Stress, expecting them to get them out fast. Alternatively, the Leads would send one drawing at a time requiring Stress to evaluate as many as 300 similar drawings one-at-a-time. This caused Stress to mark up a drawing, and later to mark up a very similar drawing for the same mistake. Tedious! Then they would get the reworked drawings again, one-at-a-time.
Some Stress Analysts had learned the impact of reviewing families of drawings. [Accelerated Stress Reviews] It would work in this situation also.
As the system constraint, Stress used their power. They demanded that the Leads bring only a full batch of similar drawings for review. That required Leads to accomplish their work in a short time. The only way to get a batch of drawings done in time was to borrow and loan resources. This was never done because loaned resources rarely seemed to return. However, they had no choice. They loaned resources to other Leads that were getting ready for stress reviews.
The stress group was able to increase their effective capacity by working on batches of similar drawings. They would mark up one drawing and check for similar issues with the others. They sent the batch back to the Lead to rework them all. Very simple and very effective.
Productivity increased 200% to 500%
The Stress Analysis group increased the system throughput by 200% to 500%. Because the Stress Analysts were the constraint resource, the Leads moving resources and sharing work between design groups, created a dramatic improvement in drawing release performance. It would not have been possible without the mental shift and focus that accompanies the Critical Chain constraints management approach.
The Senior VP on the program, an Earned Value expert, thought we had a new innovative way to game the EV system. When the schedule SPI got better, he said the cost must have gotten worse. To the contrary, the cost performance index CPI also improved. That means that we significantly changed the productivity of the whole system. Earned Value was assigned to each drawing. EV was earned when the drawing was completed. You can’t game the system.
777-300ER Derivative was fast.
The first derivative airplane, the 777-300 ER (Extended Range), using CCPM, was scheduled for 18 months, an aggressive schedule.
777-200LR Derivative was much faster, easily.
The second derivative airplane, the 777-200 LR (Long Range), using CCPM, was scheduled for 16 months, a very aggressive schedule. It had mostly the same people and this time everyone believed the data.
- 777-300ER was early and under budget.
- 777-200LR was 5 months early and under budget.
- The airplanes went together much better in the factory than previous derivatives.
- The upside is significantly faster projects, while the downside is business as usual.
Simple Work Rules
- Work on the high priority project
- Critical Chain tasks have priority over feeding chain tasks
- Earlier scheduled tasks have priority over later scheduled tasks
- The above rules are subject to buffer management decisions
- Work on the active, high priority task to completion
All tasks had due dates. However, when ahead of schedule, no one paid attention to them.
One of the engineers on the 777-200LR was asked how he liked Critical Chain.
When his Lead was asked why the engineer didn’t know they were using Critical Chain, the Lead said, “He doesn’t need to know. I give him work. He finishes it and gives it back. I give him more work. I need to know how to manage with Critical Chain. He just works on one thing at a time. It’s easy.”
“Whether you think you can or think you can’t – you’re right.” Henry Ford
“Whether you think CCPM can work or think it can’t – you’re right.”
You can only win people over once they have used Critical Chain Project Management.
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