I did a search on the NTSB database, for aircraft flagged as homebuilt in which the word "weld" is mentioned in the Probable Cause. I found eighteen cases from 1998 to 2016, roughly one per year. Three resulted in fatalities.Originally Posted by jim_p
http://www.wanttaja.com/weld_failures.pdf
Ron Wanttaja
Thanks Ron,
Not many in 18 years, certainly short of an epidemic we need to remedy with draconian measures.
How many more than ONE do you need - before you consider this a problem. Now you see that three (3) fatalities are on file.
I have spent 40 years as an NDT specialist and teacher.
I have taught more than 2500 people everything I know about Non Destructive Testing and how it affects every facet of our industrial life.
In all these years, we have been behind the curve when it comes to mechanical failures.
Very rarely do we ever get the chance to find a defect and then go out to all the similar aircraft types to search for possible defects.
99% of the time we are called in after an aircraft part has failed and someone has died.
I thought my concerns regarding welding defects could be used as a preventative cautionary warning that might keep at least one person alive.
Well I tried - I am no longer interested in this discussion.
Have a nice day.
Wow........I bet Transport Canada can hardly wait........
Concern for safety of builders and pilots is certainly prudent, but inferring that everyone who has built an aircraft without "certification" is a danger to society is over the top. A much more reasonable approach would lead to more credibility.
Last edited by Sam Buchanan; 10-09-2018 at 06:30 PM.
I count two. The third was the result of the pilot not terminating the flight when told of a problem with the airplane. That's two in almost twenty years. I'm OK with that, not happy but OK.
Stuff happens with metal construction, wood, composites. Crying wolf doesn't help. I'm done too......
Thanks Ron and cwilliamrose for looking up the actual data. 2 is too many of course but way down on the list of things to worry about according to the actual data. So either non-certified welders aren’t complete disasters, or the parts are over engineered in general, or people are taking the welding jobs to experts more than we know.
Of course, if someone who was a good welder (certified or not) wanted to help teach and share expertise and things to be careful of, in a civil, even friendly and cheerful manner, that would be great. Might even make some friends, grow some skill sets, make planes safer, and save some planes and lives.
Well this certainly got weird fast. The thing is I get where nixrox is coming from, as I work in NDT and materials as well, however there has to be a dose of reality there as I also work in prototyping where you don't have the advantage of making 100 identical parts to study and fine tune a process and procedure. We get one shot to do it. This is why I have preached using the most conservative approach to constructing any one of part. Is there shoddy welding in some homebuilts....honestly yes. Are there failed welds both OEM and homebuilt.....yes. Luckily most are caught and the designs robust enough to survive to repair so nobody hears about them. Should we rely on this robustness alone....absolutely not. There is room for education and improvement in the homebuilt area and the EAA is in an excellent position to do so, if they should ever choose.
Aaron - do you have any x-ray film to prove that your welds are defect free? How about Ultrasonic weld inspection reports by a certified UT Tech? How many CGSB or ASNT level 2 or 3 certifications do you hold?
You cannot weld on certified aircraft without a license.
You cannot fly an aircraft without a license.
You cannot perform maintenance on a certified aircraft without a license.
You cannot perform NDT inspections on aircraft without a license.
You cannot weld anything in the oil or construction industry without a license and a successful welder test at the site.
What makes you think anyone should be allowed to weld on an aircraft without a license or any recognized training or testing?
Did you notice that not one of the sarcastic responding trolls or naysayers mentioned the EIGHTEEN (18) destroyed aircraft due specifically to weld problems since 1996.
I rest my case and will let Darwin's theory root out those individuals who like to tempt fate.
As a person with some NDT knowledge, I would have expected you to have a better handle on defect propagation and structural analysis.
Good luck by the way.
@nixrox Which part of “experimental - amateur built” is it that you don’t understand?
Experimental GA aircraft are pretty minimal for what they have to do. Most of the parts of the plane are life critical. E-AB builders understand and accept that and make their own choices about what to buy, hire out, or do themselves. Your attitude of “only the pros should ever do that” is pretty much the opposite of the whole point of E-AB.
Nobody is taking you very seriously because you are barging in insulting everyone without offering anything to actually help people weld better. That’s the only way you are going to make a useful difference here.
1998-2016, actually. That's just about one accident a year, or roughly 0.5% (half a percent) of homebuilt accidents. Only three of them resulted in fatalities, accounting for 0.3% of the fatal accidents.
Not saying a reduction wouldn't be nice, it's just not a major contributor to the homebuilt accident rate. The same amount of effort to "fix" other problems would save more lives.
Here's a summary of the number of fatal accidents for given causes. This, again, covers the 1998-2016 time period. There were about 960 fatal accidents in this time period.
Note that there were almost as many accidents involving suicide as there were fatal accidents involving bad welds. As far as I can determine, the weld issues just aren't that common.
Accident Cause Pilot Miscontrol Manuevering Low Alt Engine Failure - Undetermined Continued VFR into IFR Conditions Fuel Exhaustion Midair Pilot Incapacitation Internal Engine Issues Failure to Recover from Aerobatics Fuel Starvation CG or Weight Fuel System Issues Carb Ice Fuel Contamination Inadequate Preflight Reduction Drives Fire Disorientation Ignition Carb Mechanical Oil System Cooling System Wake Turbulence Airframe Icing Suicide
Mind you, bad welds only make the NTSB database if an accident meets the reporting criteria. Likely there were more failed welds, that either caused little or no damage or were detected on the ground prior to takeoff.
No one's doubting that homebuilt welds could be better, just that bad welds aren't that major a problem.
Ron Wanttaja
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