This is a serious concern and something you would have thought would be addressed concurrently, as part of the design process, not after a plane is already in service. With design for manufacturability and design for maintenance increasingly being discussed in engineering circles, one would hope that companies in the aerospace sector would be aggressively evolving thei engineering workflows to address maintenance and repair issues around composites as part of the early design stage.
It's almost impossible to exaggerate how critical the proper safety and repair procedures are. After the well-known American Airlines Flight 191 crash in May, 1979, NTSB investigators concluded that the engine separated from the plane in flight after the engine pylon was damaged during incorrect maintenance procedures. The bottom line was that a fork lift had been used to support the engine while it was being detached from the wing during maintenance -- a procedure that the plane's manufacturer "did not encourage." The plane crashed about a mile from Chicago O'Hare Airport, killing 273.
Doesn't the FAA etc. look at the components and materials as the designs are finalized? You would think that they would so that the individual pieces can be approved and they don't miss some critical hidden part. Even at that, the Dreamliner is SO far along that I am really surprise that any new safety concerns would be brought up.
Any major launch to market that I have been involved with starts with a stockpile of spare parts on the shelf to minimize the effects of any failures to the end user. Seems like Boeing started without a net. Hopefully, the repair processes are clearly laid out for composite repairs as noted in the article. A lot of lives depend on these processes being in place.
I've worked on parts and assemblies before and there are parts that are designated as Critical to Quality. You would think that list on an airplane would be kind of big and I can't believe there are things that are "not encouraged" by the manufacturers that companies actually do as part of their standard process. However, it's not tough to believe that with the tough economic times that we are all under, that proper training is not always done and procedures are not necessarily followed.
I agree that I am surprised the FAA would not be looking at the designs as they go along much like UL does. I would expect them to come in, do a little preliminary review and then recommend the tests that should be performed before the product is allowed to be used.
Or if that did happen why this group would then review the Dreamliner and bring out concerns. Something just doesn't sound right. I kind of feel like we are not hearing the entire story.
I am kind of interested in the way the report makes it sound like the GOA has safety concerns. But then they make it sound like the concerns are not huge safety risks. And they are not insurmountable. But does the FAA have the proper procedures in place to overcome this issues? And the GOA is not sure. As a frequent flier I guess I'de feel a lot more comfortable if someone would get together and make some kind of statement. This sounds like two government agencies that are not communicating that may in fact be doing the same job.
I read the concern being that the FAA does not have a strong data base and of set of protocols for planes made of higher percentages of composite materials, not that the plane is not safe or composites are not good. It is a who came fisrt/ chicken or the egg: safety protols for repairs have been established over the years based on 1.) materials used in plane (higher perecentage of metal vs. composites) and 2.) issues that have driven closer inspections in the filed (failures). Years ago, people said steel strong - steel good, and when aluminum and titanitum as lighter weight materials were introduces, people rightly questioned do we have adequate checks in place to insure these lighter weight materials will perform. Now the same questions are being asked about composites. I think it is just evolution, and the protocols for inspection of higher percentage use of composites will come as a natural necessity.
The trick is being able to understand the "stresses" and stress points in the composites and this will take time to understand (history). Once these are understood and easily located (X-ray spectroscopy, etc), the problem areas can be fixed and/or maintained/replaced quite easily. My concern is do they have enough history to know how the components react to continual stresses and flex fatigue???
Using light strong fibrous composites to build an airplane. How novel! Ideas like that don't grow on trees. Or do they?
But in all seriousness, the problem of repairing composites, including wood has always been a pain. It is distressing that Boeing, especially with their history of wood structures would ignore the fact that some day some poor bastard would have to fix the thing.
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