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United States, AZ, Phoenix
Joined Jun 2006
588 Posts
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Your last paragraph is a little condescending. There are engineers all around the world that use engineering tools, network synthesis, simulation modeling, statistical and failure analysis and, yes, they can assign percentages to failure modes that occur in engineering systems. Just because someone doesn't want or know how to do it doesn't mean it can't be done. It just takes a little more time and money. |
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Kevin,
NTSB reports are factual. No hidden meanings, no emotion built in. My last paragraph you refer to states known factors and that there may have been others that are not known to the investigators or you and I. I think the sentence there that you may read as condescending is the one referring to casual readers and what that reader gets from the info in the report. I suspect the majority of those taking part in this thread have not read the full report and because of that, some may give more weight or value to some sound bites pulled from the text in the report. I am one of those engineers. I have those tools and know how to use them. I have been party to other NTSB investigations. I have designed airplanes, built them and gone thru testing. You are right, we can use these tools to determine probability and predict failures. We can also use these tools post event to simulate the event and develop possible scenarios, maybe dozens, that all result in the same failure event and post failure accident. In that last paragraph of mine, I wrote the left elevator trim system failed. This seems to be a true statement based on photos and the report as well as my own skills as an engineer. The next sentence states it is not possible to know the precise sequence of events meaning that in that very short period of time prior to the accident. For example, we cannot know with 100% certainty that event A, then C then G(2), then X, occurred prior to the tab link failing. Maybe it was X first. Maybe C really had nothing to do with the combination of C, G(2) and X. It is possible that, for example, the worm locking fiber ring in 2 of the nuts had no part in the sequence of events while the 3rd nut may have been a contributing factor. The canopy sucking open at high speed is an issue but it may be totally unrelated to the trim system failure yet was mentioned in the report. Lastly in that paragraph, I wrote in reference to assigning a % of effect to each of these possible factors leading up to the failure of the trim system. If the exact sequence of events is not known nor the precise events included in the failure sequence, it is not possible to give weight to each. Sure, it is possible to pick the set of events to include in an analysis and then run simulations of several sequences and assign value to each. Maybe one of those sims will be identical to the actual events. Several could end with the same final result. The report lists no precise sequence of events nor lists a % contribution of the listed Possible factors in the failure sequence. This was a very tragic event and very high profile. The investigators gave this high priority and far more investigative resources than they would have if the same failure and crash would have happened a week before the races and only Jimmy was lost. Yet still, there is no exact time line of the failures given in the report because it just isn't possible to be 100% factual with that info. The report is fact not supposition or estimation. You wrote: "Just because someone doesn't want or know how to do it doesn't mean it can't be done. It just takes a little more time and money." I agree with you. It is easy to simply look the other way and do nothing. Just because the report indicates FAA was not consulted on changes doesn't mean they didn't seek out advice from others who may or may not have been party to the investigation. The report doesn't address this. The FAA inspectors available to Jimmy's group may not be the best source for experienced advice with respect to these airplanes. The FAA people you dealt with during the assembly of your glasair kit had advice and knowledge to share with you that was of value to you and your kit assembly with any deviations from standard kit components or procedures you may have included. However, it is possible those same people wouldn't know enough about 500mph racing mustangs to give proper advice. We cannot know from the info in the report. The report doesn't state how much time was spent designing and evaluating the mods to the airplane and systems nor what engineering tools where used. It doesn't address how much money was spent. The report simply states what is known to the investigators at that time. Look, I knew Jimmy and I know his family. I know some of the guys who have worked on that plane over the years. I know others who were in race planes that very race, that very day and saw the events from their cockpit. I have friends who were there on the ground and had just left that very area to go get some food. I know the guy who manages the local sports bar here. With all that, I have my opinions of what happened and who screwed up simply based on my experience as an engineer, airplane designer/builder, vintage airplane restorer, etc. My educated gut, if you will. But, I have not once shared that opinion here in this thread because it is not part of the report. I have only discussed the report and how others read into it without basis of fact for the statements they make here in this thread. I wrote that it is inaccurate, based on the info in the report, for a casual reader to take a few words such as "FAA" or "lock nuts" or "approval," for example, and turn that into "Hey bubba, lets try this." Likewise, just because the report cites no documented evidence that the GG team went to the FAA for advice on the changes to the airplane (some of which where done before Jimmy owned the airplane) doesn't mean they didn't get "off the record" FAA advice or get the advice from another more qualified source. Kevin |
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South Africa, WC, Cape Town
Joined Dec 2010
4,983 Posts
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If they did in fact seek outside advice on the mods why was it not documented?
Good engneering practice states research, develop options through a basic design package, model those packages, understand the stresses and strains, then develop the most promising option for retaining structural integrity whilst increasing performance. Why reuse old bolts? The bolts in an F1 car have similar specs, they are replaced before every Grand Prix. I just don't see any evidence of any failure mode analysis. If there was, surely it would have surfaced during the investigation. The people working on that plane would have a vested interest in supplying such info to show they did their homework. If they did their homework it would be mentioned in the report and during the hearing. No such evidence it appears was presented. Maybe it hasn't been found or maybe it does'nt exist. |
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Tim,
Again, the report contents do not state who the investigators talked to or those who chose to give a "no comment" answer. Could be some didn't want to be involved and get hooked into any possible litigation that may come from this. Maybe there were no others. The report simply doesn't have this info in it. Which is my point. What ifs or who ifs etc. are not part of the report. The report does contain the exact FAA required logbook entry by the pilot at the time of testing. This statement is on page 6 paragraph 1.3.2. Agreed on your definition of good engineering practice. The report doesn't outline the exact engineering practices employed in the development of the mods to this airplane and therefore, based on the content of the report, it is not possible to compare what was done to what others consider typical practice in engineering. I have not had any discussions with anyone related to this airplane to know what engineering practices were employed. Since the report doesn't outline this info, it is not possible to discuss the scope of such engineering in the context of this thread about the report. Was the age of a bolt specifically noted as causal? Is the age of the bolt true reference to the condition of that bolt? I do not see reference to the age or condition of bolts in the report. Please point me to where it is in the report. I do see reference to the screws used to mount the trim tabs. The report states how the screws failed, on bending and overload, but I see no reference to the age of the bolts. The report doesn't state the bending and shear failures of the screws was as a result of in flight failure or ground impact. It just states the darn things were bent back and forth and broke. The report didn't state that the trim system should be redesigned to have bigger screws or find the screws inadequate for the job at hand. Just which ones were found to be broken when they looked at the parts post accident. I am not personally familiar with F1 racing cars other than the ones I have seen at the races and in museums. I have not worked on F1 racing cars so I cannot comment to the accuracy of the statement you make that the bolts are replaced before each race and if so, is that every bolt or just some found to be critical based on experience by F1 car chiefs after having seen failures of those bolts in the past. If the latter, this is true in aviation as well. Some parts, including some bolts, are known time life parts and are changed at intervals of flight hours or calendar years as required for safe operation. I do not have an approved P51 maintenance manual to be able to see which, if any, components on a mustang are timed life. You are correct. There is no info in the report with respect to failure mode analysis. This is why it seems silly to have statements made in this thread in reference to if it was done or not. The report is not all inclusive. It doesn't contain every detail, every note, every bit of info that was found during this investigation. It is simply a brief on what the NTSB found to be "probable cause" and the basic data and facts to support that. No doubt there is a hangar full of data collected and that it was all reviewed. It just isn't all here in this thread or in the report. So it is inaccurate to assume something never happened just because it is not listed in this report. This report is not evidence is it simply a public statement of the findings of an accident investigation board of which only part is about the airplane. The rest is about the NCAR event, event layout and safety at the event all of which are said to have been implemented for the recent 2012 races. |
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Arvada, CO
Joined Sep 2007
523 Posts
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I really don't think that there is much to compare between F1 or any modern auto racing and Reno Air Race planes. It is much more like vintage car racing, in budgets, mindsets and technology. If it were like F1 or Lemans series, you would see incredible development with technology and materials with huge development teams backed with large corporations. You don't have the best and brightest aerodynamicists and aeronautical engineers going into development of these planes like you do with F1 or Lemans series teams.
From what I can tell, unlimited race planes are generally owned by wealthy individuals. My guess is that most of the guys there to win for bragging rights, not for the success or marketing of their businesses or to further the technology. Technology in these old planes trickles down and applied where possible. They are old, loud and crude by modern technological standards. Not to say that they aren't complex or incredibly fun to watch. I work with some local pro auto racing teams doing electronics. The amount of work that goes into these cars is incredible. You might have a car that looks like your wife's sedan with a body kit and some race tires, but what is underneath has only the absolute minimum left, like engine block casting, door handles and basic layout of the stock components. The bodies are all carbon fiber developed with hours and hours of CFD and wind tunnel time. The mechanicals are designed and simulated by computers before the parts are all custom machined out of the most suitable materials, treated and plated or painted. Every system is thoroughly monitored and logged in use. The drivers may be the rock stars, but it is the guys that are behind the PCs, running machines and turning wrenches that make it possible. My guess is that guys like kjkimball are the aircraft builder equivilents. In auto racing, you have tech inspections and series requirements and lots of experience from years of racing, same as in aircraft racing. You also have equipment failures and just plane screw ups that can cause problems, crashes and deaths. As I recall, Ayrton Senna died as a result of a failure of the steering linkage in his F1 car in 1994. This year Paul Dallenback crashed his 1600hp 2000lb car on Pikes Peak when his throttle stuck open, missing spectators by inches. This EASILY could have been similar to the Reno Air Race crash had he gone through the crowd just a few feet away or in other places on the track.
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South Africa, WC, Cape Town
Joined Dec 2010
4,983 Posts
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seen plenty video's like that one. Its not unique. In Europe incidents like those were ignored until a Ford RS2000 went off the raod and took out spectators. Rally rules changed, the technical rules changed drastically, outlawing over night the super powerful Group B cars, crowd control became stricter. The sport became more professional over night.
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Joined Aug 2012
1,931 Posts
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We have rally's were I live the crowd control still doesnt work as its meant to on paper. A lot of spectators park themselves on the outside apex of bends just ridiculous to see at times when you know the car is going to hit them if it strays off course. The marshals do try to do what they can but I've seen some spectators itching for a punch up if they are asked more than once to move to a safer place. Looking on the positive side, its not a bad thing sometimes to allow the culling of a few neanderthals.
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Good thing Kevin is on here to explain what is really going on.
Doug Chronkite is OK, but way off in a lot of his comments. If you haven't been around sport aviation in the USA, it hard to know the reality of sport. That's Tim's problem at the root, SA aviation is different, CAA in UK is different, etc. Too bad Leeward was so cozy with RARA President Mike Houghton. If I had been boss, that airplane would've never left the ground in 2010 unless a ton of stuff was done including a real test series by a test pilot. Then the chain would've been broken for 2011. Leeward's **** was well known, his crew and attitude about racing hadn't ever changed in the 40 years he'd been intermittantly competing. He never did any good because of his wanting strategy and operation. Totally preventable, the only way this will happen again is with the totally out of control Jet Class, LLC. Love that they are an LLC. Signed, retired race pilot |
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CB |
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Well,
I may have overstated the Jet Class peril, if Rick Vandam is to be able to ride herd on them as he did this year they will be alright (he is a check pilot and has large sway in how things happen and who flies). The cowboy mentality that has been long gone in the Unlimited Class (with the exception of the Leeward anomaly) was really raising it's head in Jet. This year looked better by far. Signed, retired race pilot... |
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South Africa, WC, Cape Town
Joined Dec 2010
4,983 Posts
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