An underside fuselage panel fell of a 787 today. Nothing (apparently) serious or safety-related (the panel is detachable anyway), but it was big – around 2.4 m 1.2 m. Could this also be due to parts not quite fitting together as described in this thread?
John F-L From: Stanislav Jakuba Sent: Tuesday, October 15, 2013 11:40 PM To: U.S. Metric Association Cc: U.S. Metric Association Subject: [USMA:53330] RE: Presenting the metric system to the innumerate Citing with kilopascal, I would not step into a (Boeing) airplane designed by inch people and made by metric people to Boeing, I-P documentation. Here is why. Inch people are somewhat familiar with metric, but this does not apply in reverse. Trust me on this one. I have been training metric engineers and technicians to work with inch standards: It is possible to teach them but impossible for them to grasp the stuff to the extend that that knowledge is of much use. Many of them never heard of such terms as an inch or ounce. Or the third angle of projection. On the other hand, I have been training inch people to work "according to the globally prevalent (metric) standards" with good results. Not only because being systematic the material is easier to teach but the students also remember it because they have lots of metric knowledge already (without realizing it). I should also bring up the possibility of confusion metric people face having no notion that I-P standards in GB are different than in U.S. A gallon is a gallon to them. Who would ever want to trust these people with manufacturing an I-P (what I-P) airplane? Fortunately nobody has been. By coincidence, the latest Metric Today published my article Did Metric Help Russians in the Space Race? I am attaching it here for those who (shame of them) are not USMA members. Notice in one of the last paragraphs the story of the British I-P documentation and the impossibility of manufacturing to it in the U.S. Stan Jakuba On Mon, Oct 14, 2013 at 11:07 PM, Kilopascal <[email protected]> wrote: Carleton, It is a completely untrue statement that foreign companies are/were forced by Boeing to work in inches and pounds. Get that notion out of your head. Foreign or domestic companies that are set up to work in metric can not work in USC. If they don’t have the tooling and the know-how it can not be done. What instead is done, is the metric capable plant will convert the inch dimensions to millimetres and produce it from the conversions. Problem with conversions is the tolerances. Some rounding is always necessary when converting and even if tolerances are considered, accumulative tolerances can be a pain to keep track of. This is the problem Boeing ran into. When errors are made and they need to be traced to the source, it becomes a costly nightmare to see which conversions and tolerance stacking's produced the error. This can be very costly. Boeing has no choice when it comes to outsourcing. Some countries have laws requiring certain content from their own country be a part of the finished product before they agree to buy. Japan for example may require that Boeing produce part of the plane in Japan. I’m not sure if this example is true or not, but I am just trying to give a reason why Boeing may have to outsource some production. Japan’s choice to purchase Airbus products really has nothing to do with metric versus USC but much to do with the problems plaguing the Dreamliner. Boeing is a has-been trapped in the past and a victim of its own arrogance. It wants to be a world-class company but it insists on using obsolete units of measure. The problem with this is it can’t effectively have its products designed in the metric system so they can be produced anywhere with out a need for conversions and tolerance issues. Airbus on the other hand can have its components made anywhere and be assured the units they design to are the units used in the production no matter where they are made. Airbus can take advantage of the world market, Boeing can not. Don’t be surprised if Boeing is out of business in 5 years. [USMA:53326] RE: Presenting the metric system to the innumerate Carleton MacDonald Sun, 13 Oct 2013 13:15:36 -0700 It is interesting to note the orders Boeing (inch-pound design) is losing to Airbus (metric design). Even from such stalwarts as Japan Air Lines, which just made a huge A350 order. I wonder how many of the Boeing 787 problems are due to forcing the foreign suppliers to manufacture in inchpound, and how many are just because of engineering incompetence. -------------------------------------------------------------------------------- No virus found in this message. Checked by AVG - www.avg.com Version: 2014.0.4158 / Virus Database: 3614/6743 - Release Date: 10/11/13
