Posted: 11/5/2009 2:13:56 PM EDT
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From today's (11/5/2090) Aviation Week Website: Late December first flight target for 787 Posted by Guy Norris at 11/5/2009 1:24 PM CST Boeing is pointing more and more to a late December first flight target for the 787, and definitely more than a month away as I suggested in my previous (admittedly late night) blog post. As the company points out, although the side-of-body modification is complete on ZA001, preparations for flight remain on hold until validation tests on static test airframe ZY997 are completed. Even then there’s more waiting to go through while Boeing and the FAA evaluate the results and confirm the design meets the required goals. Only at this point will ZA001, or ‘AP1’, go back into pre-flight – a roughly three week process. Testing on ZY997 - the pacing item for now (Guy Norris) So let’s look at what that means in terms of potential timing. Boeing isn’t saying too much about the details of the static testing schedule but, depending on how long the results take to be checked and confirmed, we could be looking at pre-flight activity (gauntlet tests) getting underway around the Thanksgiving holiday (Nov 26). If all went well that would shunt the first flight window to approximately the Dec 17-24 period. If more issues crop up the company still has the remaining week in December to achieve its target of flying by year-end. So is this a long-looked for chance for Boeing to finally celebrate the festive season with a first flight, or more likely a major slice of overtime for the Boeing flight test team? Either way there’s a busy December in store for Everett. Comments (0) | Permanent Link |
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From today's (11/5/2090) Aviation Week Website: Late December first flight target for 787 Posted by Guy Norris at 11/5/2009 1:24 PM CST Boeing is pointing more and more to a late December first flight target for the 787, and definitely more than a month away as I suggested in my previous (admittedly late night) blog post. As the company points out, although the side-of-body modification is complete on ZA001, preparations for flight remain on hold until validation tests on static test airframe ZY997 are completed. Even then there’s more waiting to go through while Boeing and the FAA evaluate the results and confirm the design meets the required goals. Only at this point will ZA001, or ‘AP1’, go back into pre-flight – a roughly three week process. Testing on ZY997 - the pacing item for now (Guy Norris) So let’s look at what that means in terms of potential timing. Boeing isn’t saying too much about the details of the static testing schedule but, depending on how long the results take to be checked and confirmed, we could be looking at pre-flight activity (gauntlet tests) getting underway around the Thanksgiving holiday (Nov 26). If all went well that would shunt the first flight window to approximately the Dec 17-24 period. If more issues crop up the company still has the remaining week in December to achieve its target of flying by year-end. So is this a long-looked for chance for Boeing to finally celebrate the festive season with a first flight, or more likely a major slice of overtime for the Boeing flight test team? Either way there’s a busy December in store for Everett. Comments (0) | Permanent Link is it really that far behind schedule? 
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Personally I think composites are not as durable as metal or as easily reapaired as sheet metal. I think composite resins are too brittle or become too brittle after age/ultraviolet/flex and cycles etc. Time will tell. my master's research paper was titled "On the Initiation and Progression of Matrix Cracking in Toughened Carbon Fiber Composites", and was entirely funded by Boeing CAG (Commercial Airplane Group). to gather data for this 1" thick report, i spent about 1K hours in a mechanical lab –– using mil-spec 2 part aircraft epoxy to attach aluminum tabs to 1" x 12" x [0]12* carbon fiber test coupons, creating repeatable defects in the coupons with a precision diamond saw instrument, mounting the coupons in the jaws of a very large Instron tensile machine (w/ 50HP hydraulics), and running static, creep, fatigue, and long term cycle tests at both elevated and depressed ambient temperatures. virgin coupons were supplied by Toray (who is but one manufacturer of the CF stressed parts on Boeing airframes, see link), and processed coupons were supplied by Boeing and several research organizations. the processed coupons had been, for example, soaked in JetA for months, or heated in a bath of hot hydraulic fluid, or artificially aged using high UV/ozone/etc conditions. progression of matrix splitting from the defect point was monitored using both acoustic and optical means, with the equipment for the former being supplied by a military airframe contractor. it consisted of transducers which were attached to the coupon using coupling gel and very sensitive amplification stages feeding precision analog-to-digital converters. using special analysis software run on the resultant datastream, it was possible to track the location of cracking (as it occurred) from the acoustic emissions in the coupon. your background? ar-jedi (*) composite material layups are denoted by the fiber direction (in degrees) and layer count. a [0]12 layup is 12 layers of prepreg material, with all fibers aligned in the same direction. a [0]6[90]6 layup is the same thickness, but 6 of the layers have the fibers oriented in the direction perpendicular to the other 6. there are innumerable combinations. |
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Quoted: my master's research paper was titled "On the Initiation and Progression of Matrix Cracking in Toughened Carbon Fiber Composites", and was entirely funded by Boeing CAG (Commercial Airplane Group). to gather data for this 1" thick report, i spent about 1K hours in a mechanical lab –– using mil-spec 2 part aircraft epoxy to attach aluminum tabs to 1" x 12" x [0]12* carbon fiber test coupons, creating repeatable defects in the coupons with a precision diamond saw instrument, mounting the coupons in the jaws of a very large Instron tensile machine (w/ 50HP hydraulics), and running static, creep, fatigue, and long term cycle tests at both elevated and depressed ambient temperatures. virgin coupons were supplied by Toray (who is but one manufacturer of the CF stressed parts on Boeing airframes, see link), and processed coupons were supplied by Boeing and several research organizations. the processed coupons had been, for example, soaked in JetA for months, or heated in a bath of hot hydraulic fluid, or artificially aged using high UV/ozone/etc conditions. progression of matrix splitting from the defect point was monitored using both acoustic and optical means, with the equipment for the former being supplied by a military airframe contractor. it consisted of transducers which were attached to the coupon using coupling gel and very sensitive amplification stages feeding precision analog-to-digital converters. using special analysis software run on the resultant datastream, it was possible to track the location of cracking (as it occurred) from the acoustic emissions in the coupon. your background? ar-jedi (*) composite material layups are denoted by the fiber direction (in degrees) and layer count. a [0]12 layup is 12 layers of prepreg material, with all fibers aligned in the same direction. a [0]6[90]6 layup is the same thickness, but 6 of the layers have the fibers oriented in the direction perpendicular to the other 6. there are innumerable combinations. So.. umm.... could um.... could you cut it open with a light-saber? |
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my master's research paper was titled "On the Initiation and Progression of Matrix Cracking in Toughened Carbon Fiber Composites", and was entirely funded by Boeing CAG (Commercial Airplane Group). to gather data for this 1" thick report, i spent about 1K hours in a mechanical lab –– using mil-spec 2 part aircraft epoxy to attach aluminum tabs to 1" x 12" x [0]12* carbon fiber test coupons, creating repeatable defects in the coupons with a precision diamond saw instrument, mounting the coupons in the jaws of a very large Instron tensile machine (w/ 50HP hydraulics), and running static, creep, fatigue, and long term cycle tests at both elevated and depressed ambient temperatures. virgin coupons were supplied by Toray (who is but one manufacturer of the CF stressed parts on Boeing airframes, see link), and processed coupons were supplied by Boeing and several research organizations. the processed coupons had been, for example, soaked in JetA for months, or heated in a bath of hot hydraulic fluid, or artificially aged using high UV/ozone/etc conditions. progression of matrix splitting from the defect point was monitored using both acoustic and optical means, with the equipment for the former being supplied by a military airframe contractor. it consisted of transducers which were attached to the coupon using coupling gel and very sensitive amplification stages feeding precision analog-to-digital converters. using special analysis software run on the resultant datastream, it was possible to track the location of cracking (as it occurred) from the acoustic emissions in the coupon. your background? ar-jedi (*) composite material layups are denoted by the fiber direction (in degrees) and layer count. a [0]12 layup is 12 layers of prepreg material, with all fibers aligned in the same direction. a [0]6[90]6 layup is the same thickness, but 6 of the layers have the fibers oriented in the direction perpendicular to the other 6. there are innumerable combinations. So.. umm.... could um.... could you cut it open with a light-saber? Or could Chuck Norris break it? Did all you Dr. McSmartyPants types think about that? Huh? |
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So, ar-jedi what were the results of your research?
I have no doubt carbon fiber/kevlar/fiberglass is durable, the resins that bond them are my question, what kind of lifespan will this airframe have? I'm just expressing my opinion. I've been working aircraft maintenance and overhaul for more than 25 years. I said time will tell. 25 years from now tell me how a 787 has held up compared to a metal ship. Just sayin... |
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So, ar-jedi what were the results of your research? I have no doubt carbon fiber/kevlar/fiberglass is durable, the resins that bond them are my question, what kind of lifespan will this airframe have? I'm just expressing my opinion. I've been working aircraft maintenance and overhaul for more than 25 years. I said time will tell. 25 years from now tell me how a 787 has held up compared to a metal ship. Just sayin... The AV8B Harrier has been operating with an all-composite wing for 25 years and isn't scheduled for retirement for another 5 years. For all the problems the Harrier might have, structural problems with the wing are not on the list, at least that I know of. Granted a military airplane sees far fewer hours and cycles than a commercial airplane, but combat military airframes aren't exactly treated with kid-gloves either. I believe battle damage tolerance and field repairability are among their design requirements. |
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Design for damage tolerance, and that includes at fastener holes, adds significant conservatism that is not imposed on metallic structure. It's a major consideration that can determine the sizing beyond that required to simply carry the mechanical loads.
Damage tolerance means the safety of the airframe is only partly compromised by undiscovered damage. Fastener holes wear through fretting and the matrix is crushed under bearing stresses of about 40 ksi magnitude depending on the particular matrix. Skins and doors are banged by equipment and tools or tool boxes are dropped, causing subsurface delamination that is invisible from the outside. Hopefully every incident of this type will be reported so a mechanic can investigate - and that means that everyone around the airplane has to take the initiative to report their own incident. The problem with really thick laminates is the impossibility of discovering delaminations with the coin tap method. And then there is the added complication of access to both sides of the laminate to inspect with other tools; it's impossible in many cases. A tolerant airframe can suffer small delaminations of limited size and certain distribution. The trick is to either keep them from growing (hard to do) or discover them with expensive NDT method (expensive and hard to do at all, let alone with confidence). |
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Here comes the Dobbs House catering truck,piloted by Jimmy,who makes $8.00 an hour........Design for damage tolerance, and that includes at fastener holes, adds significant conservatism that is not imposed on metallic structure. It's a major consideration that can determine the sizing beyond that required to simply carry the mechanical loads. Damage tolerance means the safety of the airframe is only partly compromised by undiscovered damage. Fastener holes wear through fretting and the matrix is crushed under bearing stresses of about 40 ksi magnitude depending on the particular matrix. Skins and doors are banged by equipment and tools or tool boxes are dropped, causing subsurface delamination that is invisible from the outside. Hopefully every incident of this type will be reported so a mechanic can investigate - and that means that everyone around the airplane has to take the initiative to report their own incident. The problem with really thick laminates is the impossibility of discovering delaminations with the coin tap method. And then there is the added complication of access to both sides of the laminate to inspect with other tools; it's impossible in many cases. A tolerant airframe can suffer small delaminations of limited size and certain distribution. The trick is to either keep them from growing (hard to do) or discover them with expensive NDT method (expensive and hard to do at all, let alone with confidence). 
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I love the fact that I'm geting lots of "thesis paper" opinions and "theory'...
A 787 has not flown yet. Until it does and it logs significant flight cycles, I'm going to continue to be a sceptic. Composite is known for its rigidity and stiffness. Not something a long life airframe needs. Rigid, stiff and inflexible results in cracking and structural failure. I don't think composite compares in flexability and longivity to sheet metal. The sheet metal of the 1950's is not what is used on aircraft today. Like I said, I'm not an engineer or metalurgist or chemical engineer. I'm a mechanic. I can change any component. I can do any repair, sheetmetal or composite, potted or cooked. I'm familiar enough with composite tech repair and the current, 787 fastener tech to feel thet I want to see a 787 fly for a few years before I'd commit my company to laying heavy odds on that as THE future of aviation. |
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I'll believe it when I see it. Personally I think composites are not as durable as metal or as easily reapaired as sheet metal. I think composite resins are too brittle or become too brittle after age/ultraviolet/flex and cycles etc. Time will tell. Don't know too much about aerospace composites, do you? It isn't the fiberglass you get at the local Ace Hardware. I've flown plenty of airplanes manufactured by Boeing Plastic Works, and they are VERY durable... and, repairable (but requiring different techniques - easier in some ways, harder in others). When you see the wings of a Super Hornet flex under a 7.5 G turn, you'll understand. I also saw a yellow-shirt back a Super Hornet's stabilator into another Super Hornet... damaged the stabilator. A little fancy glue and it was all better. I also saw an aileron get dinged up - the whole thing had to be replaced...
On the JSF, the entire tail section contains certain fluid-based systems. If those systems ever fail, it's cheaper to replace the entire tail section than repair it. Like I said, different techniques - not necessarily harder. Your 25 year background in aviation maintenance has given you many great insights, but it has also institutionalized you. Much as my Dad has an immediate dislike for FADEC's (whereas, I love the damn things), you have an immediate dislike for composites. This institutionalized mindset happens to most (especially in aviation) around the 20 year point. Composites have been doing some damn good work for MANY years and logged MANY flight cycles. They are ABSOLUTELY the way of the future (as are FADECs). |
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I'll believe it when I see it. Personally I think composites are not as durable as metal or as easily repaired as sheet metal. I think composite resins are too brittle or become too brittle after age/ultraviolet/flex and cycles etc. Time will tell. Don't know too much about aerospace composites, do you? It isn't the fiberglass you get at the local Ace Hardware. I've flown plenty of airplanes manufactured by Boeing Plastic Works, and they are VERY durable... and, repairable (but requiring different techniques - easier in some ways, harder in others). When you see the wings of a Super Hornet flex under a 7.5 G turn, you'll understand.
Your 25 year background in aviation maintenance has given you many great insights, but it has also institutionalized you. Much as my Dad has an immediate dislike for FADEC's (whereas, I love the damn things), you have an immediate dislike for composites. This institutionalized mindset happens to most (especially in aviation) around the 20 year point. Composites have been doing some damn good work for MANY years and logged MANY flight cycles. They are ABSOLUTELY the way of the future (as are FADECs). Well you keep flyin'em and breakin'em and I'll keep fixen'em. The ship you fly right now is an amalgamation of mostly sheet metal/forgings and composite secondary structures. The 787 is professed to be an ALL composite airframe. ALL composite, so I have my doubts. I'm sure if its viable, to provide years of glue sniffing repair work for me and my ilk. Have I professed to be an expert on composite tech? NO! Have I expressed my doubts based upon the composite failures and repairs I've witnessed? YES! So you can pack your attitude back up the orifice it came from. Has the 787 flown yet? NO! I'm simply saying until I see a 787 log significant flight cycles, I'm not a "believer" that the 787 is the ultimate in NEW aircraft tech. . |
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I'll believe it when I see it. Personally I think composites are not as durable as metal or as easily repaired as sheet metal. I think composite resins are too brittle or become too brittle after age/ultraviolet/flex and cycles etc. Time will tell. Don't know too much about aerospace composites, do you? It isn't the fiberglass you get at the local Ace Hardware. I've flown plenty of airplanes manufactured by Boeing Plastic Works, and they are VERY durable... and, repairable (but requiring different techniques - easier in some ways, harder in others). When you see the wings of a Super Hornet flex under a 7.5 G turn, you'll understand.
Your 25 year background in aviation maintenance has given you many great insights, but it has also institutionalized you. Much as my Dad has an immediate dislike for FADEC's (whereas, I love the damn things), you have an immediate dislike for composites. This institutionalized mindset happens to most (especially in aviation) around the 20 year point. Composites have been doing some damn good work for MANY years and logged MANY flight cycles. They are ABSOLUTELY the way of the future (as are FADECs). Well you keep flyin'em and breakin'em and I'll keep fixen'em. The ship you fly right now is an amalgamation of mostly sheet metal/forgings and composite secondary structures. The 787 is professed to be an ALL composite airframe. ALL composite, so I have my doubts. I'm sure if its viable, to provide years of glue sniffing repair work for me and my ilk. Have I professed to be an expert on composite tech? NO! Have I expressed my doubts based upon the composite failures and repairs I've witnessed? YES! So you can pack your attitude back up the orifice it came from. Has the 787 flown yet? NO! I'm simply saying until I see a 787 log significant flight cycles, I'm not a "believer" that the 787 is the ultimate in NEW aircraft tech. . I do see your point, but I'm fairly certain the guys at Boeing have thought through a lot of the pesky details. That it hasn't flown hardly means it is going to be a maint. nightmare. Metal breaks in a host of different ways. Composites break in other (and occasionally, more spectacular) ways. *shrug* 6 of one or half-a-dozen of the other. As for my attitude... I tend to get annoyed when grumpy old farts poop all over the shiny new technology that allows us to do really cool stuff. Embrace the new tech or die with the old. |
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One of my previous flight students is working on parts for the 787, says they are pretty far behind, the composites are a huge challenge for the engineers and they are working to make sure those parts don't pose major problems for the plane in the future. I predict december will not happen for the 787. |
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One of my previous flight students is working on parts for the 787, says they are pretty far behind, the composites are a huge challenge for the engineers and they are working to make sure those parts don't pose major problems for the plane in the future. I predict december will not happen for the 787. Be that as it may, kudos to Boeing and their engineers for pushing the technological envelope. |
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Quoted: Quoted: One of my previous flight students is working on parts for the 787, says they are pretty far behind, the composites are a huge challenge for the engineers and they are working to make sure those parts don't pose major problems for the plane in the future. I predict december will not happen for the 787. Be that as it may, kudos to Boeing and their engineers for pushing the technological envelope. Oh yes I agree. being one of the guys who will probably fly the thing one day, I want them to take all the time they need. I just want them to design it so it is capable of all the limits...not like the tail on a airbus.  |
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I'll believe it when I see it. Personally I think composites are not as durable as metal or as easily repaired as sheet metal. I think composite resins are too brittle or become too brittle after age/ultraviolet/flex and cycles etc. Time will tell. Don't know too much about aerospace composites, do you? It isn't the fiberglass you get at the local Ace Hardware. I've flown plenty of airplanes manufactured by Boeing Plastic Works, and they are VERY durable... and, repairable (but requiring different techniques - easier in some ways, harder in others). When you see the wings of a Super Hornet flex under a 7.5 G turn, you'll understand.
Your 25 year background in aviation maintenance has given you many great insights, but it has also institutionalized you. Much as my Dad has an immediate dislike for FADEC's (whereas, I love the damn things), you have an immediate dislike for composites. This institutionalized mindset happens to most (especially in aviation) around the 20 year point. Composites have been doing some damn good work for MANY years and logged MANY flight cycles. They are ABSOLUTELY the way of the future (as are FADECs). Well you keep flyin'em and breakin'em and I'll keep fixen'em. The ship you fly right now is an amalgamation of mostly sheet metal/forgings and composite secondary structures. The 787 is professed to be an ALL composite airframe. ALL composite, so I have my doubts. I'm sure if its viable, to provide years of glue sniffing repair work for me and my ilk. Have I professed to be an expert on composite tech? NO! Have I expressed my doubts based upon the composite failures and repairs I've witnessed? YES! So you can pack your attitude back up the orifice it came from. Has the 787 flown yet? NO! I'm simply saying until I see a 787 log significant flight cycles, I'm not a "believer" that the 787 is the ultimate in NEW aircraft tech. . Sir, you really are in over your head in a discussion about composite structures. From your earlier post, I'll just say that composites are not more rigid than metal structures. In truth, the isolated materials are less stiff than aluminum, and that is one of the reasons different strategies of structural arrangement are requried. You may be making a commom error in confusing strength with stiffness; composites lack the ability to fail gracefully under over load by yielding as found in a properly designed metallic structure. The laminate fails catastrophically, all at once and completely. This is a different consideration than stiffness. The F-18 and the AV-8B rely on composite primary structure. The fuselage, wing, and empennage skins are not secondary structure, they are primary load carrying elements and perform the same function as the skins on an all metal semi-monocoque airplane. Any of these airplanes would collapse under load without their skins. The 787 is not 100% composite. That is impossible for real airplanes. However it does have some elements such as skin stiffeners that are composite that would probably work out better if they were metal. We'll see about that soon enough. Composite materials have two strengths in airplane applications; as relatively flat structural elements that are designed by stability, and to make shapes that are difficult to fabricate from metal. Composites are a failure, every time, where strength sizes the part, especially when weight and space constrain the design of the part - and they always do. The empennage attach lugs on the Airbus airplanes are an example of a part that should never make its way onto an airplane - non redundant attach lugs that are extremely thick, which drives the diameter and weight of the attach pins up, and yet fail catastrphically in net section tension (where the fastener pulls tears the edge of the lug out). A metal part would yield and might get out of kilter, but the damn empennage won't fall off. You're also mistaken about the metal alloys in use today. We do use a few new alloys, such as 7050's and some others, but the greater part of the most common alloys have been around since WWII. The only difference is the names they have now. Don't mistake me as a rabid advocate of composite airplanes, I'm not. But I have to recognize their benefit when used correctly. In my experience, I know of two composite parts that actually saved weight over the metal counterparts, and that was two short keel webs about 4 feet long in Bird of Prey. The joint loads were small and there weren't a huge number of penetrations for subsystems, so the part could be designed for stability which exploited the low density and the 'thickness squared' effect to save a couple of pounds. Plus they were flat and easy to make without buying a bond tool. |
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Difference in cultures here.
I'm quite sure the engineers, designers and the host of others involved in the design and construction of this aircraft have researched the crap out of it. But Willz license is on the line when he goes to work. My ass is on the line when I go to work. If we don't have warm fuzzies about the equipment we operate, all the engineer-speak and reassurances in the world aren't going to make us sleep well at night. Nothing personal, just different upbringing. As for me, I'm planning on retiring off the MD80. I sleep like a baby at night... TC |
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Difference in cultures here. I'm quite sure the engineers, designers and the host of others involved in the design and construction of this aircraft have researched the crap out of it. But Willz license is on the line when he goes to work. My ass is on the line when I go to work. If we don't have warm fuzzies about the equipment we operate, all the engineer-speak and reassurances in the world aren't going to make us sleep well at night. Nothing personal, just different upbringing. As for me, I'm planning on retiring off the MD80. I sleep like a baby at night... TC Thank you AA717driver 
My opening comments illustrated, I'm NOT (obviously) nor did I claim to be an engineer. Alot of things look good on a CAD program. Real world nuts and bolt application is totally different. (in this case fibre and resin) You technocrats need to chill out, I'm simply expressing my doubts about what was initially touted as an ALL composite airframe. I've since found out up to 50% of the airframe is in fact composite and is STILL an unproven/ flight tested airframe. I expressed my doubts about its lifespan/durability and the practical application of in the field repairs. I myself get plenty of O.T. from the MD80, the B737, B757, B767 and B777 not so much, but they have their maintenance intensive weaknesses. I will say this about 'ancient" technology like the MD80 it may not be the cutting edge but it will fly safely with more items on MCO/inop than any other commercial aircraft. (I'm sure some technocrat will be along shortly to tell me how wrong I am  )
Just speaking from my experience 
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On the DC-9/MD80 if it's broke, you either don't need it or it's REALLY F'ED UP and going to the shed. 
I always get into it with engineers because they "know" an actuator will work because they've seen the design, know the specs, sourced the parts and wrote the instructions for its manufacture and installation. Pilots and mechanics "know" it will work when it's received, taken out of the box, installed in the aircraft and tested. But, deep down, we know it can fail the very next time you power it up. Difference in culture.
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On the DC-9/MD80 if it's broke, you either don't need it or it's REALLY F'ED UP and going to the shed.
I always get into it with engineers because they "know" an actuator will work because they've seen the design, know the specs, sourced the parts and wrote the instructions for its manufacture and installation. Pilots and mechanics "know" it will work when it's received, taken out of the box, installed in the aircraft and tested. But, deep down, we know it can fail the very next time you power it up. Difference in culture.
TC That's a stupid broad brush you're waving around. I'll leave you with this; the engineers you encounter in the field are not those that designed the airplane, selected the parts, or tested the systems. In the end, your jobs are to perform the maintenance as instructed in the manuals for the airplane, backed up by your basic training as a mechanic, and the aid given by the factory when clarification is needed. Virtually every problem that arises in the field, apart from those caused by wear and tear, is caused by a mechanic or his boss that either deviates from the maintenance procedure, albeit with good intent without complete understanding of the consequences, or simply cuts corners because, "That's how we do it." I've seen the notebooks in a major airline's shop. Licenses issued by the government are granted after measuring minimum standards. They do not measure excellence. Your attempt to insult me is wasted effort. I expect I have a thicker skin than either of you. I've also worked on both sides of the hangar door. One of you needs to look up "technocrat", too; it doesn't mean what you believe it means. Besides that, you might go back an re-read my post. I know it's more than two sentences long, but you might discover that I more or less agree with your position about the airworthiness of the 787. I might also be a bigger skeptic than either of you, too. |
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From Aero E:
"Virtually every problem that arises in the field, apart from those caused by wear and tear, is caused by a mechanic or his boss that either deviates from the maintenance procedure, albeit with good intent without complete understanding of the consequences, or simply cuts corners because, "That's how we do it." I've seen the notebooks in a major airline's shop. " Thata's a pretty broad, self serving, statement as it implies that there aren't any inherent "design problems" or "manufacturing quality control problems". There are some pretty glaring historical exmples (DC-10's falling apart for verious reasons (UAL Sioux City, AAL-Chicago, Turkish DC-10 with cargo door failure, 737 rudder runaways––numerous, etc. etc. to the contrary. No doubt that the mainters take some liberties with the "approved data", but to pin all of the issues on faulty maintenance does a disservice to the maintainers. |
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On the DC-9/MD80 if it's broke, you either don't need it or it's REALLY F'ED UP and going to the shed.
I always get into it with engineers because they "know" an actuator will work because they've seen the design, know the specs, sourced the parts and wrote the instructions for its manufacture and installation. Pilots and mechanics "know" it will work when it's received, taken out of the box, installed in the aircraft and tested. But, deep down, we know it can fail the very next time you power it up. Difference in culture.
TC That's a stupid broad brush you're waving around. I'll leave you with this; the engineers you encounter in the field are not those that designed the airplane, selected the parts, or tested the systems. In the end, your jobs are to perform the maintenance as instructed in the manuals for the airplane, backed up by your basic training as a mechanic, and the aid given by the factory when clarification is needed. Virtually every problem that arises in the field, apart from those caused by wear and tear, is caused by a mechanic or his boss that either deviates from the maintenance procedure, albeit with good intent without complete understanding of the consequences, or simply cuts corners because, "That's how we do it." I've seen the notebooks in a major airline's shop. Licenses issued by the government are granted after measuring minimum standards. They do not measure excellence. Your attempt to insult me is wasted effort. I expect I have a thicker skin than either of you. I've also worked on both sides of the hangar door. One of you needs to look up "technocrat", too; it doesn't mean what you believe it means. Besides that, you might go back an re-read my post. I know it's more than two sentences long, but you might discover that I more or less agree with your position about the airworthiness of the 787. I might also be a bigger skeptic than either of you, too. Aero––First off, I wasn't trying to insult you or any other AE. I was pointing out the different mindset of those who design/build the product and those who use it. Not casting aspersions on the engineering field, just pointing out the difference in though processes. You might go back and re-read my post. I don't build them, I fly them. And if I ever find the dipshit who designed the sun visors on the first half of the 767/757's with that stupid vise grip/hex nut contraption, I'll kick his ass! We don't bring the USAToday to read, it's to use as a sunshade.  Oh, and another thing––one cup holder on the 757? I guess no one up there in SEA drinks sodas. One can, one cup of ice, one cup holder...
TC I'd rather fly a 40 year old DC-9 than a brand new Airbus.
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One of the problems we face in the office is a generation of engineers now that never, ever worked on anything. Not even changing a spark plug in a lawn mower.
The other major problem is schedule pressure. Unfortunately, the greater majority of worker bees, and 100% of the management, are more interested in meeting the schedule with something, rather than parts and assemblies that are low cost, light weight, have good fatigue life, and are easy to maintain. Frankly, they just don't care, either from being beaten over the head for a long time, out of ignorance about the down stream effect of their decisions, hoping it all works out, or in hopes problems can be fixed later, sometimes accepting risk without justification or a plan for managing the risk. Take a look at the structural AD's for any product; it's a long list. When I look at one, generally the cause is simple to find and could have been avoided with no more cost or weight. In fact, I can recall only one fatigue failure I've ever worked on that could not be explained (at a tooling boss in the outboard closure rib of the main wing fuel tank), and after several "fixes" that didn't work, we took the boss out altogether. The commercial stuff is easy to troubleshoot. Fortunately I've worked on only one BCA project. I have to stop there without additional comment. |
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One of the problems we face in the office is a generation of engineers now that never, ever worked on anything. Not even changing a spark plug in a lawn mower. ... you void the warranty, though, if you do that, don't you???? One of the best vehicles I've ever owned was (ok, several) an EA82 Subaru - they were designed, as near as I can tell, to be easy to work on my shadetree mechanics. EVERYTHING was accessible, the fuel pump was on a skid outside the tank, the fuel filter was in the engine bay, there was plenty of space (you could pull the heads without taking the engine out - rare for a flat 4), etc. I haven't seen engineering like this recently. :( |
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From Aero E: "Virtually every problem that arises in the field, apart from those caused by wear and tear, is caused by a mechanic or his boss that either deviates from the maintenance procedure, albeit with good intent without complete understanding of the consequences, or simply cuts corners because, "That's how we do it." I've seen the notebooks in a major airline's shop. " Thata's a pretty broad, self serving, statement as it implies that there aren't any inherent "design problems" or "manufacturing quality control problems". There are some pretty glaring historical exmples (DC-10's falling apart for verious reasons (UAL Sioux City, AAL-Chicago, Turkish DC-10 with cargo door failure, 737 rudder runaways––numerous, etc. etc. to the contrary. No doubt that the mainters take some liberties with the "approved data", but to pin all of the issues on faulty maintenance does a disservice to the maintainers. I was pushing your button. Your comments above put a burr under my saddle. In the end, we're on the same side. I do everything I can to prevent headaches from the manufacturing floor to service in the fleet. I've been known to refuse sign off on drawings because the parts made from them would essentially be defective for one reason or another. My signature on that drawing means that I can attest to its airworthiness; similar to a log book signature. |
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Quoted:
One of the problems we face in the office is a generation of engineers now that never, ever worked on anything. Not even changing a spark plug in a lawn mower. ... you void the warranty, though, if you do that, don't you???? One of the best vehicles I've ever owned was (ok, several) an EA82 Subaru - they were designed, as near as I can tell, to be easy to work on my shadetree mechanics. EVERYTHING was accessible, the fuel pump was on a skid outside the tank, the fuel filter was in the engine bay, there was plenty of space (you could pull the heads without taking the engine out - rare for a flat 4), etc. I haven't seen engineering like this recently. :( I had a 76 Volvo that had enough clearance to slide under without jacking the car and a tray at the front of the engine compartment for tools and parts. On the one hand that is a good thing. On the other hand, I'm glad I don't have to work on that worn out piece of junk anymore. Now I have a car that I may need to jack to change the oil. |
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AeroE
I understand your defense and respect of the newest composite technology. It's some really cool shit 
You obviously have an intimate relationship with a carbon/kevlar fiber domestic partner. Good for you. Tell me how many flight cycles you get out of it. 
In the world where the rubber meets the runway, an aircraft that is light as a feather and has the thrust of the space shuttle on three pounds of jet-A and can tell you when it has a fever and it needs it's mommy is some engineers' dream. I'm all for making aircraft lighter, faster, more cost efficient, and above all safer. When my company starts 787 initial training you can bet I'll be in one of the first training classes. But I have no illusions, the 787 and it's related technology is pop culture among those on the aerospace R&D frontier but from my perspective, especially with an aircraft that has YET to even fly,... I'll believe it when I see it. Space shuttle and military applications are not the same as commercial aircraft. I know the military ships log alot of time carry alot of weight, they also are not treated like an airborne movie theater and public city bus. Get back to me when it's logged a few thousand cycles, some heavy turbulence, some over weight landings, had a couple of belt loaders and bag tugs rammed into it, then tell me how this theoretical aircraft compares to good old aluminum and steel. 
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AeroE I understand your defense and respect of the newest composite technology. It's some really cool shit
You obviously have an intimate relationship with a carbon/kevlar fiber domestic partner. Good for you. Tell me how many flight cycles you get out of it.
In the world where the rubber meets the runway, an aircraft that is light as a feather and has the thrust of the space shuttle on three pounds of jet-A and can tell you when it has a fever and it needs it's mommy is some engineers' dream. I'm all for making aircraft lighter, faster, more cost efficient, and above all safer. When my company starts 787 initial training you can bet I'll be in one of the first training classes. But I have no illusions, the 787 and it's related technology is pop culture among those on the aerospace R&D frontier but from my perspective, especially with an aircraft that has YET to even fly,... I'll believe it when I see it. Space shuttle and military applications are not the same as commercial aircraft. I know the military ships log alot of time carry alot of weight, they also are not treated like an airborne movie theater and public city bus. Get back to me when it's logged a few thousand cycles, some heavy turbulence, some over weight landings, had a couple of belt loaders and bag tugs rammed into it, then tell me how this theoretical aircraft compares to good old aluminum and steel.
Go back and read my posts, especially if you think I admire, advocate, defend, or respect the use of composites in airplanes. I already said at least one time that I'm not an advocate, in fact I think it's a monumentally poor idea. Trouble is, there's no way to convince the mouth breathers until it has been out in the field. We've been listening to morons selling this silliness since the 70's (actually a little longer). The rubber is finally hitting the road now in a large airplane. They'll soon enough learn what it delivers. |
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Quoted:
Quoted:
AeroE I understand your defense and respect of the newest composite technology. It's some really cool shit
You obviously have an intimate relationship with a carbon/kevlar fiber domestic partner. Good for you. Tell me how many flight cycles you get out of it.
In the world where the rubber meets the runway, an aircraft that is light as a feather and has the thrust of the space shuttle on three pounds of jet-A and can tell you when it has a fever and it needs it's mommy is some engineers' dream. I'm all for making aircraft lighter, faster, more cost efficient, and above all safer. When my company starts 787 initial training you can bet I'll be in one of the first training classes. But I have no illusions, the 787 and it's related technology is pop culture among those on the aerospace R&D frontier but from my perspective, especially with an aircraft that has YET to even fly,... I'll believe it when I see it. Space shuttle and military applications are not the same as commercial aircraft. I know the military ships log alot of time carry alot of weight, they also are not treated like an airborne movie theater and public city bus. Get back to me when it's logged a few thousand cycles, some heavy turbulence, some over weight landings, had a couple of belt loaders and bag tugs rammed into it, then tell me how this theoretical aircraft compares to good old aluminum and steel.
Go back and read my posts, especially if you think I admire, advocate, defend, or respect the use of composites in airplanes. I already said at least one time that I'm not an advocate, in fact I think it's a monumentally poor idea. Trouble is, there's no way to convince the mouth breathers until it has been out in the field. We've been listening to morons selling this silliness since the 70's (actually a little longer). The rubber is finally hitting the road now in a large airplane. They'll soon enough learn what it delivers. Quoted:
Standby for re-evaluation. You tedious bastard. Maybe YOU should look up "Technocrat" and not the Wiki definition either. So you agree with my take but tell me I'm ill equipped to discuss composites? 
I see a future in politics for you. |