HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
  |  REGISTER  |  LOGIN  |  HELP
Blogs
Blog

Composite Aircraft Repair Advances

NO RATINGS
Page 1 / 2 Next >
View Comments: Threaded|Newest First|Oldest First
Beth Stackpole
User Rank
Blogger
Certification a no-brainer
Beth Stackpole   12/6/2011 6:45:17 AM
NO RATINGS
I would think it goes without saying that there should be new standards and certifications for technicians charged with the responsibility for vetting out and orchestrating the fix of composite structures in need of repair. Composite materials are very different that what's required to repair metal and steel structures. I don't know why we need a government report to tell us an heavy investment in training and skills building is necessary!

ScotCan
User Rank
Platinum
Composite Aircraft Repair Advances
ScotCan   12/6/2011 8:39:15 AM
NO RATINGS
@Beth.The government gets involved because the private sector tends to gloss over problems in order to maintain market share. That being said too much government involvement stifles progress. The Bombardier decision is more likely based around deHavilland's experience over the years where their tough aircraft stood up to some primitive operating conditions...dings and dents being the standard operating experience. Also the flight cycle time for the Dash 8 on the west coast averages 58 minutes which is rough on a structure where fatigue is concerned. Aluminum-Lithium is a difficult material to work with but (again) Fleet Industries in Ontario has had long experience in building (and repairing) such structures.It will be interesting to see where Bombardier goes with this since the C series is a big change from the smaller aircraft built previously.

Ann R. Thryft
User Rank
Blogger
Re: Composite Aircraft Repair Advances
Ann R. Thryft   12/6/2011 2:45:31 PM
NO RATINGS

I think the answer is a bit of both. Beth, the industry apparently has been working on solving this problem along with the FAA. At least, that's what they all tell us. But it's quite difficult to find out any details. And that's where ScotCan's point comes in. As the report delineates, industry has been extremely secretive regarding the details about their materials--the type of details which must be well known for determining when and how to repair--in the name of trade secrets. 


Alexander Wolfe
User Rank
Blogger
Re: Composite Aircraft Repair Advances
Alexander Wolfe   12/6/2011 2:50:14 PM
NO RATINGS
I'm impressed by the breadth of your recent coverage on composites, Ann. I'm wondering if you see new standards emerging out of the FAA as regards composites repair, or will we see industry-standard practices come into play first, which will become de facto methodologies for both repair and recycling?

Ann R. Thryft
User Rank
Blogger
Re: Composite Aircraft Repair Advances
Ann R. Thryft   12/7/2011 12:54:27 PM
NO RATINGS

Thanks, Alex. The news just keeps coming out on this subject. Regarding standards, that's a really good question. One of the key critiques in the GAO report was the point that you can't base repair standards and best practices for composites on the same ones that were created for metal. There are too many differences across the board, and making the same assumptions or using the same templates would be ineffective and dangerous. That may be another reason why we're not hearing much yet about the details of repair whens and hows. I suspect it's a WIP.


TJ McDermott
User Rank
Blogger
Re: Composite Aircraft Repair Advances
TJ McDermott   12/7/2011 9:29:40 PM
NO RATINGS
While repairs require more effort, composites would seem to be more damage resistant than an aluminum structure.

I looked for a video I'd seen several years ago: Boeing demonstrating a large skin section held vertically, and airline executives offered the chance to whack it with a sledge hammer.

I cannot find that video so this one will have to do:

http://www.youtube.com/watch?v=7dtk818WSiU&list=PLE618FBD35463D3BA&index=2&feature=plpp_video

Bombardier may go for traditional repair techniques on the areas in danger of ground support damage, but if composites shrug off the damage that would ding aluminum, then composites would seem to be the better bet.

 

 

Ann R. Thryft
User Rank
Blogger
Re: Composite Aircraft Repair Advances
Ann R. Thryft   12/13/2011 1:28:04 PM
NO RATINGS

TJ, your points are well taken. The biggest problem of all in composite repair, though, compared to metal repair, is the lack of knowledge to identify damage in the first place, since it's much more difficult to detect. The next biggest problem is figuring out how to repair so many different materials with so many different uses and so many different possible procedures. And, by extension, lack of knowledge there, as well.


Cabe Atwell
User Rank
Blogger
Re: Composite Aircraft Repair Advances
Cabe Atwell   5/28/2014 2:34:51 AM
NO RATINGS
How are the composite materials when it comes to stress fracturing? Believe it or not, with aluminum, airline companies bolt a patch over the cracks until it can be sufficiently repaired, which may take months and in some cases years.

Dave Palmer
User Rank
Platinum
Aluminum-lithium alloys
Dave Palmer   12/6/2011 12:49:55 PM
NO RATINGS
@Ann: The title of this article seems to be out of step with its contents, to say the least.  Obviously Bombardier doesn't think composite aircraft repair is advancing enough to justify using composites in the CSeries fuselage.

Which aluminum-lithium alloys is Bombardier using? There was an article on this website a few months ago about Alcoa's new third-generation aluminum-lithium alloys, which were developed cooperatively with Bombardier.

 

Rob Spiegel
User Rank
Blogger
Is this just a transition period?
Rob Spiegel   12/6/2011 2:29:56 PM
NO RATINGS
Interesting story, Ann.

I'm curious as to whether this is a transition time for composite materials or whether there is something intrinsic to composites that makes detection of problems and repair more difficult for composites than it is for more conventional materials.

Ann R. Thryft
User Rank
Blogger
Re: Is this just a transition period?
Ann R. Thryft   12/6/2011 2:49:46 PM
NO RATINGS
Rob, that's the $64,000 question. I think the answer here is also 'both." Composites are definitely moving forward in aerospace, as shown by all the aircraft makers using them in greater amounts. And detection of at least certain types of damage is difficult, but apparently not impossible. 

Charles Murray
User Rank
Blogger
Beyond material strength
Charles Murray   12/6/2011 10:12:44 PM
NO RATINGS
This is a classic example of the need to beware that what looks good on paper may not always be so. As design engineers, we are often trained to consider matters of stress and strain -- bending, shear, torsional capacity, etc. But here we have a situation where the composite is apparently appropriate in matters of material strength, but not in matters of maintenance. Obviously, maintenance is a huge consideration for aircraft. In 1979, an American Airlines flight leaving Chicago O'Hare crashed, killing 271 people, after a design flaw left the engine pylon vulnerable to maintenance damage.

Dave Palmer
User Rank
Platinum
Re: Beyond material strength
Dave Palmer   12/7/2011 10:23:19 AM
NO RATINGS
@Charles: You're absolutely right; materials selection involves many considerations besides the material's response to stress and strain -- which can be complicated enough, since the material may respond very differently at different temperatures and strain rates, and its properties may be different in different directions.  But how a given material will perform in your application also depends on its location in the galvanic series, among other things. Cost and manufacturability are always major concerns, too. Then there are externalities such as recyclability and end-of-life issues, sustainability and lifecycle emissions, etc.  And -- although I may be somewhat biased in this regard! -- this is why having a good materials engineer is a necessity.

Charles Murray
User Rank
Blogger
Re: Beyond material strength
Charles Murray   12/7/2011 3:32:15 PM
NO RATINGS
Follow-up from last night's comment: After I mentioned the American Airlines flight that crashed in 1979 after a design flaw left it vulnerable to maintenance damage, I tried to remember where I had once read about that accident. Here's the answer: Our distinguished columnist, Henry Petroski, wrote about it in his book, "To Engineer Is Human."

Partner Zone
More Blogs
The phablet wars continue. Today we welcome the Nexus 6 -- a joint collaboration between Google and Motorola.
According to a study by the National Institute of Standards and Technology, one of the factors in the collapse of the original World Trade Center towers on Sept. 11, 2001, was the reduction in the yield strength of the steel reinforcement as a result of the high temperatures of the fire and the loss of thermal insulation.
Robots are getting more agile and automation systems are becoming more complex. Yet the most impressive development in robotics and automation is increased intelligence. Machines in automation are increasingly able to analyze huge amounts of data. They are often able to see, speak, even imitate patterns of human thinking. Researchers at European Automation call this deep learning.
Thanksgiving is a time for family. A time for togetherness. A time for… tech?
The promise of the Internet of Things (IoT) is that devices, gadgets, and appliances we use every day will be able to communicate with one another. This potential is not limited to household items or smartphones, but also things we find in our yard and garden, as evidenced by a recent challenge from the element14 design community.
Design News Webinar Series
11/19/2014 11:00 a.m. California / 2:00 p.m. New York
11/6/2014 11:00 a.m. California / 2:00 p.m. New York
10/7/2014 8:00 a.m. California / 11:00 a.m. New York
12/11/2014 8:00 a.m. California / 11:00 a.m. New York
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Dec 1 - 5, An Introduction to Embedded Software Architecture and Design
SEMESTERS: 1  |  2  |  3  |  4  |  5  |  6


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Last Archived Class
Sponsored by Littelfuse
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service