In a surprise announcement this morning, Boeing announced that it is pushing back the first flight of the ZA001, the first 787. The issue leading to this postponement was a structural issue that was revealed a few weeks ago during a test on ZY997, the static test airplane that Boeing is using to test the structure of the 787.
Problem
In a test where the wing was deflected, the strain gauge measurements were not following the predictive modeling that Boeing had developed for certain areas of the sider body join. Jon Ostrower had confirmed that the area in question are 18 small areas on each side of the aircraft at section 11 (center wingbox) and section 12 (main wingbox) are joined (upper wing root). There appeared to be some damage during this test that confirmed what the strain gauges had recorded. Unconfirmed report that there was some delamination of the skin at those areas.
In a conference call today Pat Shanahan and Scott Francher said that there are several areas each about 1 to 2 sq. inches that need to be reinforced.
At this point Boeing is understanding the root cause of the problem and and are concurrently working on several different designs to fix the problem. However they still cannot give guidance at this point for first flight and first delivery.
Resolution
They still have to finalize a design then proceed with detailed design of the fix. Manufacture the parts and install them on ZY997 in order to be tested. If testing verifies the design then Boeing will retrofit all the 787 whether assembled, in final assembly, or within the supply chain with the required parts. Boeing said in the conference call that the parts will add a negligible amount of weight and should not effect aerodynamic performance of the aircraft. At one point Boeing was considering a temporary solution but decided on a permanent fix over a temporary one. Additionally, they said that ZA001 could have flown without any type of fix but did not want to risk it.
Testing and Production
Of great concern is how does this new issue effect further testing and production. ZA001 was on the verge of starting final gauntlet testing followed by taxi tests. Boeing stressed that those activities will continue in the coming days though I'm not sure if they would do the rejected take off (RTO) tests until after the reinforcements have been installed.
In terms of production Boeing said that the other 5 test flight airplanes will continue with their final assembly and testing activities as this issues affects none of those activities. ZA002 is out on the flight line and will soon turn on its engines and will continue with it's pre-flight ground tests as will the other test flight aircraft. They will pull them out of the assembly building when they are done to proceed with their test activities on the ground.
Additionally all production activities will continue uninterrupted whether that is at Everett final assembly or at any of the partner production sites. When the fix is finalized and in production, all airplanes will be retrofitted with these parts in the supply chain or on the tarmac.
Unknown
Now this all leaves the 787 schedule up in the air. Scott Francher said that he will give a revised schedule outlook in a few weeks regarding first flight, certification and first delivery. Saj at fleetbuzzeditorial.com said he expects a two to three month delay pushing the entry into service to 2nd quarter of 2010. Lastly, with an unknown amount of time because of this new delay I wonder how Boeing will fill this time in order to retire risk and/or retire certification paperwork yet to be done but doesn't need actual flight time to complete it?
This story is part of the continuing saga of the 787 and I plan on continuing to be on top of it. You can read what my fellow bloggers have also written:
Fleetbuzzeditorial.com's 787 5th delay post
Flightblogger's 787 delay post
Mike Mecham's 787 article
Tuesday, June 23, 2009
Subscribe to:
Post Comments (Atom)
Posts
6 comments:
Most of us are shocked and confused by the announcement and the uncertainty that follows.
There are questions of veraciy and the degree of the problem that may not have been properly addressed.
In addition there are questions as to why this problem was not addressed a longtime ago when there were issues with the wingbox. It is all confusing and disturbing .
We certainly hope this is just a small remediation but we will not know for quite a while and Boeing's record of credibilty has severly damaged our confidence.
While disappointing, this should not be an issue of shock, confusion, or credibility.
The damage appears to be in areas adjacent to the wing box. I have no inside knowledge to know how this area was affected by the wing box redesign, or what the scope of the redesign might have been.
However, there's an old saying that the difference between theory and practice is that, in theory, there's no difference between theory and practice. The same idea applies to design and implementation. You can address a problem by designing a fix, but you cannot know that the problem is fixed until the design is implemented, and tested.
Further, large-scale issues such as loading, stress, and interaction between components can only be tested at integration or systems-level testing. This is exactly why there are test plans and test aircraft, not only the flying aircraft such as ZA001, but also test articles such as ZY997.
The wing loading test, conducted less than two months ago, was such an integration test. And, considering that the test could have destroyed the wings, wing box, or related areas of the aircraft, it was conducted on an expendable "test article," specifically 787 serial number ZY997. This test could only be run on a fully assembled aircraft.
While the initial results appeared to be a "pass", Boeing's engineers had additional instrumentation on ZY997, and conducted additional investigations into the test results. This is when the defects were discovered.
I have worked in software development of very large, complex, life-critical systems (specifically, telephone switching systems and networks). From my experience, this defect was discovered at about the time (in the development/test process) that I would expect. Boeing's response was exactly what it should have been - a structural defect was found with serious safety issues, and the quality assurance process stopped flight testing until the defect is fixed.
Boeing has also been very open and transparent about the defect and their process, so again, they're doing things right. Whatever other issues there have been with the 787 program, and there have certainly been some serious problems, this delay was appropriate, and handled correctly.
And yes, it was disappointing, but it was exactly the right thing to do.
Diane Wilson, Thank you for the informed perspective.
Many of us are left in the dark and the shares of Boeing are being punished more today. We assumed that the process picked things up during the respective phases of testing and have been surprised by the late discovery.
It will be some time before there is an better overview with new schedules and before that period there will be uncertainty and doubt and even skepticism.
There is an assumption that the heavy testing would be completed before a first flight was announced but this was not the case with Boeing. And that has happened too many times now.
Realistically, for any large, expensive, high-visibility project with long lead times for both manufacturer and customers, there's not much alternative to announcing project milestones and dates, well ahead of project completion.
Equally realistically, when there are safety or reliability issues involved, critical flaws can be found at any point in testing. That includes flight-testing as well as pre-flight tests. There's a very real possibility that flight tests will reveal equally serious problems, with the potential to delay deliveries.
Also, keep in mind that development and test for large, complex projects is not a linear process. Many things have to be done in parallel, and that's what we've seen here - pre-flight preparation and and structural testing running concurrently. Without this, a project the size of the 787 probably wouldn't ever be finished.
I'm not surprised that Boeing's stock is taking a beating. People take these milestone dates as guarantees, and that's something that can never be. You never want to miss dates like this, but it would be far worse to meet the date in spite of known structural issues, and for someone to die because of a known and un-fixed defect.
You are describing a set of risks that extend to the very last test of the program and you are saying that these risks can always appear at a given time.
Boeing purports to be a manufacturer of aerospace vehicles.It is owned by its shareholders and has responsibilities to them too.
It is Boeing's role to inform its shareholders in an honest and clear way. Not to exaggerate nor minimize the progress of its programs. When it embarks on a program it is to assess the risks and the rewards.
There has been some sort of disconnect here about information and the nature of the endeavor. If Boeing had said it would take three years, then there would of been the needed patrience and assessment. But Boeing made promises and did not clarify the nature of the testing so as to highlight the attendant risks. When it claimed that intermediate testing went so well as to shorten the process, one inferred that certain accomplishments were in place and the next stage was to follow.
Then the President gives an enthusiastic interview and confirms flight. There is an inference of knowledge and understanding...there is something misleading about the way Boeing has handled the original supply chain problem, the strike, and now this. It is not covered by the engineering parallel testing safety concept that is now being used to explain management failure.
Building planes is Boeing business. They are aware of the process and the risks and they should be able to communicate them clearly. IThey have not done this and their failure has been consistent
This is an engineering exculpation to cover all mistakes made by the management and the project manager.
Clearly the original modeling was inadequate and it came back to bite the project a few days before flight.
These dramatic large project excuses just cover up the failure to execute properly and then they are covered up by the technologists and engineers.
Post a Comment