Accelerated Stress Review of 43,000 parts
Case Study by Skip Reedy
A new airplane was scheduled to be certified by the Federal Aviation Administration (FAA) by June 29th. However, the FAA, always very careful, was concerned about a large number of the new parts that were approved by stress managers. The previous winter, the Stress Analysts (Engineers) that verify that the parts are strong enough and safe for flight had been on strike for 40 days with the other aircraft engineers This concern wasn’t raised by the FAA until early May. Two months is a very short time for a complex product in a big company.
My manager, David, called me into his office, and saying without even a hello, “The Director of Engineering asked his managers, ‘Can you guys give me a simple guess, or even a wild guess, as to how many man-hours might be required for these design reviews the FAA is asking for?’ ”
In response David said he shrugged, “I can’t even give you a Rough Order of Magnitude estimate until I know at least a little about what’s involved and how many design groups will need to review their parts.”
In clarification, David added to me, “There are at least 43,000 newly designed parts that need our Stress Analysts to verify that the proper approvals were made. They must all be completed two weeks before the certification date of June 29th. Stress says they don’t have the manpower to support such an endeavor. It’s May 12th. You have four weeks. You must get it all done by June 16th. Personally, I don’t see how it can be done. We don’t even have a list of the parts yet. This may be your opportunity to show what your Theory of Constraints (TOC) can do to improve a process.”
To begin with, we identified 104 Lead Engineers who would need to give their drawings to a few Stress Engineers for approval. Normally, a Lead Design Engineer sends each drawing separately to Stress for review. A Stress Engineer analyzes the load the part must take to determine if it’s strong enough.
(A list of about 5700 assemblies and the 43,000 parts would not be available for two weeks, until at least May 24. I also found out I would only have two Stress Engineers to do the reviews. Then the parts list grew to 140,000.)
My first thought was, “Maybe even TOC can’t get this much work done fast enough!”
My next thought was that this was quickly becoming an example of what I have learned to be –
A Perfect Assignment:
High visibility; Externally mandated; Immovable deadline; No plan; Impossible. Therefore, no one will challenge how I plan to do it. Everyone thinks it can’t succeed. No one wants to be anywhere near the meltdown.
This one is mine! I can do it any way I want. No one will tell me a different way because then they would be responsible.
When we got the parts list, we filtered it so assemblies would be reviewed. We had each Lead Engineer batch his assemblies in “families” and then explain his drawings to the Stress Engineer. This radically improved the process speed. It was very much like going to Santa and asking for a stress review, without the need to sit on the Stress Engineer’s lap.
The first meeting with Santa (Stress) was June 1st and the last ones were on June 16th. After 78 meetings reviewing several thousand assemblies, the Stress Engineers found that everything was verified and nothing was missed by the managers. All original approvals had been correct. The FAA was satisfied that all was well.
This “impossible” project was completed in 12 workdays. Scheduling the review meetings with the two Stress Engineers and 104 Lead Design Engineers had been the real system constraint. This project could have been completed faster with tighter scheduling.
May 25, Thursday Partial list of assemblies and Engineers
June 1, Thursday First review meeting
June 16, Friday Reviews complete
Scheduling turned out to be the constraint. If there’s a next time — I’ll do it in three days.
An afterthought – These two Stress Engineers may have carried this batching idea to the 777-300ER Airframe Derivative program. That program used Critical Chain Project Management and the Stress Engineers were again a constraint. They used a batching system to increase their productivity 400%.
© Skip Reedy 2012