Boeing’s Dreamliner – grounded by US units of measurement?

The delay in Boeing’s “787 Dreamliner project” has been widely reported. Now an article in The Seattle Times has given rise to speculation about a link between Boeing’s problems and the units of measurement used in the US.

Dominic Gates, in an article in the Seattle Times on 1 November 2007, commented on the reasons given by the company for the six month delay on the 787 project. However, the US “Go Metric!” Forum took issue with both Mr Gates and Boeing’s management, suggesting that some of the problems could have been caused by the use of “cumbersome old units”

Others have joined in the discussion. Pat Naughtin, who was guest speaker at UKMA’s Annual Conference in July, has written to The Seattle Times. He points out how metrication of the motor vehicle industry worldwide has simplified the creation of the international supply chain, instancing production of components for Ford in his home town of Geelong in Australia. Pat’s thoughts on the costs of non-metrication are set out on his web site:

Should the problems at Boeing concern us in the UK? Possibly not. Although there are UK businesses which are sub-contractors for “pound-inch” aerospace companies in North America, the UK also has a major stake in the Airbus project, the metric rival to the 787. Nevertheless, Boeing must now reconcile the high costs of production at home with the difficulties it has discovered of moving production abroad. The outcome will certainly be of interest, if not concern, to us in the UK.

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19 Responses to Boeing’s Dreamliner – grounded by US units of measurement?

  1. Daniel Jackson says:

    I wrote this to Dominic Gates;


    Mr. Gates,

    I read your article with interest and find it difficult to believe that Boeing's world-wide partners (See are not being able build the dreamliner according to Boeing's design. Maybe Boeing is the problem and not the world-wide suppliers.

    Lets get real here. Boeing still tries to build planes as if they were in the 19-th century, using ancient units of measurements that no one in the world has any understanding of. If Boeing sends these world-wide companies drawings in non-SI units it is perfectly understandable that they can't build the parts to Boeing's specs. If you haven't a clue as to what an inch is you are not going to be able to build something in inches.

    It is really about time that Boeing moved into the 21-st century and started using the units of measure that the whole world uses instead of trying to be different. The attitude of arrogance is going to cost Boeing big time.



    His response back was:

    Who are you? Are you in the aviation world? Where do you live and what do you do for a living?

    I wonder if he got bombarded by similar letters.

  2. George Carty says:

    Wasn't Concorde built using imperial units despite the face that staunchly-metric France made up one half of the partnership?

  3. John Frewen-Lord says:

    My son has been working on producing some very small sub-assemblies (3rd tier subcontractor) for Boeing for the new 787 Dreamliner. His company are having to work in imperial for Boeing, which is very strange for them - they do almost all of their work for the automotive industry, which of course is exclusively metric world wide (including the US, where he does a lot of his work). He not sure whether there is any basis to this, but he thinks that the well publicised 6 months 787 delays due to lack of fasteners availability could be due to the fact that all the fasteners are imperial, and increasingly hard to get. He mentioned that in the work he was doing, he had to source the imperial fasteners from the US, as they were unobtainable elsewhere, which caused his company some delays in delivering the first assemblies, although they were still within schedule.

    At the moment, it is mostly speculation, but if you compound the imperial fasteners problem throughout the world, this could be the main reason why the 787 is very late. Boeing is 'proud' to work in imperial, so it is not going to admit this publicly. Personally, if I were Boeing, I would be ashamed, not proud, to be working in a mediaeval measuring system for what is supposed to be a state of the art aircraft.

  4. Mike Oxley says:

    According to the US metrication act of 1975 section 205b,
    It is therefore the declared policy of the United States--

    (1) to designate the metric system of measurement as the preferred system of weights and measures for United States trade and commerce;

    (2) to require that each Federal agency, by a date certain and to the extent economically feasible by the end of the fiscal year 1992, use the metric system of measurement in its procurements, grants, and other business-related activities, except to the extent that such use is impractical or is likely to cause significant inefficiencies or loss of markets to United States firms, such as when foreign competitors are producing competing products in non- metric units;

    (3) to seek out ways to increase understanding of the metric system of measurement through educational information and guidance and in Government publications; and

    (4) to permit the continued use of traditional systems of weights and measures in non-business activities.

    If Boeing wish to use imperial measures they need to decide whether they are a non-business activity, or just disloyal to the democratically elected US government.

  5. Historian says:

    Number of misconceptions. Note: I'm not defending the use of US units, but if you don't understand the landscape, then it's easy to laugh when you should instead cry. I would be in favor of a metric calendar and metric clock, too, as long as it's better than the ones the French abandoned back then.

    (1) US units are not "Imperial" in the common sense of Britain's 19th century third empire (India and Africa). They instead derive from Britain's 18th century second empire (North America and Caribbean). Although the length units are equivalent, the liquid units and dry volume units are often widely divergent from the Imperial units. Imperial units were standardized after the US became independent, and the US standardized its own units separately from Britain.

    (2) No disloyalty involved. Mike is just being funny. The controlling clause is "except to the extent that such use is impractical," which is a loophole a mile (or approximately 1.6 kilometers) wide. It's the same principle that allows US states to declare a budget emergency every year and override various budgeting restrictions continually so that they've never been enforced. Go find an average American on the street, and 90% of the time, they can't think metric except to the extent of a 2-liter bottle of cola. Canadians find this very amusing every time they visit.

    (3) US dominance in aviation has led to delayed metrication. Flight levels are given in hundreds of feet to this day in most of the world, including in metric western Europe. (Not Russia, though. Thank God, or at least Marx, for the Soviet Union?) US insularity in defense spending has also delayed the impact of Airbus, while the auto industry's troubles with Japanese and German competition sped up their metrication. There are other worldwide industries where US units are entrenched, such as publishing: 12-point font = 1/6 of an inch, even if you print stuff out on A paper sizes.

  6. Mike Dimmick says:


    The font example is actually quite interesting, because it historically reflected the size of the block on which the type was carved. It doesn't reflect the actual character height of the type. Two fonts of different faces, but the same nominal 'point size' can be very different in height of actual characters, and even of spaced text.

    The modern desktop publishing point of 1/72 of an inch was only fixed in the 1980s and is simply a rounding of the previous standard of 1/72.27 inches, to make it more amenable to computer software. (This comes from Adobe's PostScript; earlier rendering software such as the TeX system use the older standard).


    However, I think this may be a unit so well entrenched in its field that it won't be amenable to metrication. It's rare that anyone actually wants to know how many lines of text of a given point size fit onto a sheet of paper in modern desktop publishing; changing the typeface will cause text to reflow in any case as the width of the characters, and the spacing between them, is different for each face (with rare examples where one font has been unnaturally forced into the metrics of another, e.g. Monotype Grotesque was distorted into Helvetica's character sizes to produce Arial).

  7. CATIA Jockey says:

    I work in the aerospace industry as a lowly designer.
    From my knot hole, I can say that it would take millions upon millions of dollars (if not more) to convert to metric fasteners for airplane design.

    It's not a matter of swapping out the standard fastener with similar size metric fasteners (if they exists). Each standard fastener type and size has an enormous amount of testing, documenting and certifying data and paperwork that come along with them. Counting all the rivet, bolts, screws and mating part types that are used, the cost of converting over may even dwarf the US deficit!

    Then go ask the airlines if they are willing to live with two sets of system (standard for the older airplanes and metric for the new airplanes) you may not be able to sell them a metric airplane ever.

  8. John Steele says:

    May I simply suggest that IF that were true, no airline would even consider operating a mix of Airbus and Boeing aircraft.

    I'm sure Boeing would prefer that, but that simply isn't the case.

    I would suggest that if Boeing wants to stick to US Customary, it should stick entirely to US suppliers. I worked in the automobile industry. The big reason we converted to metric in the 70's was our own foreign operations and the worldwide supply base it opened to us.

    Expecting people who don't understand Customary units (and that includes EVERYONE but the US, because Imperial is different) to successfully manufacture in Customary, meet QC in Customary, etc, is pretty naive and probably frought with folly. Outsourcing and Customary just DON'T go together, not well, anyway.

  9. Michael Glass says:

    "Then go ask the airlines if they are willing to live with two sets of system (standard for the older airplanes and metric for the new airplanes) you may not be able to sell them a metric airplane ever."

    As Qantas flies both Airbus and Boeing planes I don't think that this problem is insuperable.

    Also, though I am no technician, if Airbus can produce aircraft with metric components, then the "testing, documenting and certifying data and paperwork that come along with" the components must be at least partly in place.

  10. Karthik says:

    CATIA -- you don't swap mid design, but instead, on new aircraft. The 747-8 would remain imperial, as much of the design is a holdover from the 747-1..400. On the other hand, the 787 should have been designed in metric. New fuselage (even the materials are new!), new engines, new avionics, new interior, new landing gears ...... you don't re-certify something you have never certified before. You certify it for the first time, and doing it in metric takes the same amount of time as doing it in imperial.

    In fact you probably drive costs down. Fasteners on the A350 are likely to be the same size as those on the 787. So, suppliers can concentrate on one line instead of two.

    Source: I work in the Aerospace industry as an engineer who has worked in both metric and imperial units.

  11. Dear U.S. Metric Fans,

    You would not believe, but the majority of the structural threaded fasteners (bolts, screws, nuts) in the Airbus are in U.S customary dimensional units (a.k.a. "inches").


    (The Editor comments:

    In 1949, Canada, the UK and the US adopted the inch-based Unified Thread Standard (UTS), which was intended to replace, among others, the BS Whitworth and the US Sellers threads. A driver of this change was the problem resulting from lack of interchangeability of equipment among the Allies in the WW2. ISO metric threads have now replaced Unified in most industries around the world, but it would appear that US dominance of the aerospace industry has ensured that Unified maintains a presence there.)

  12. eric burns says:

    With America's inch dominated industrial base steadily shrinking and metric countries output rising, the future for Americans does not look all that bright. Confirming this scenario is the prediction that a metric hating Republican President will do his "best" to perpetuate American "values" medieval measurements included. Maybe the land of the free has to hit rock bottom before it sees the errors of its ways? Hindsight will tell them eventually where they went wrong, but as so often in human affairs, by then it will be too late.
    For anyone interested here is my original post to the Seattle Times no longer accessible on this link:
    In reply to Dominic Gates article in the Seattle Times on 1 November 2007.

    "This is an interesting article for one reason only; Boeing blames everybody else, but its management for the initial 6 months delay. Its by now replaced Vice President Bair asserts that some international suppliers contracted to design and manufacture sections for the Dreamliner are incapable of doing it. “They just could not do what we thought they could, said Bair. Some of the major airframe partners on the Dreamliner have performed so poorly that Boeing won’t probably use them on future programs, he said”.
    What extraordinary statements to make! Did they not vet these companies properly before entrusting them with such demanding work? If not, who is to blame? The major metric companies, Alenia of Italy; Mitsubishi, Fuji and Kawasaki of Japan chosen to do this work are no backyard operators and know what they are doing.
    Taking that into account one cannot help but think how much cumbersome old units contributed to this delay? One can well imagine metric designers and engineers struggling with units they have no feel for nor make sense to people used to simple mm.
    If this is the case, Boeing blew the first billion dollars just to learn the obvious truth that metric users find medieval units cumbersome to work with. This is truly a high price to pay for obstinacy/arrogance.

  13. gela says:

    Difference between quantities of measuring units is easily overcoming by the appropriate coefficient, for example: 1 inch = 25.4 mm. and it's OK. But what about derived units, for example "miles per hour"? and could it be considered as unit of speed? From school's physics, we know that the speed is derivative of distance by the time. so it would be measured in units such mile in a hour (mile/hour). Otherwise we can try to subvert entire mathematics and physics trying to find a limit of distance per time when the time tends to zero but it is obvious that this attempt will result zero and therefore such concept has no meaning or utility, the same consideration may be done on other units: "gallon per minute", "revolutions per minutes" and so on. These units can result confusing. Another strange thing: the units of measure would be used to measure things or quantities and not viceversa, for example, in metric system the pitch of threads are measured in millimeters. English systems the thread's pitch are used to measure one inch: threads per inch. So, some times inch is used to measure and some times to be measured.
    The systems of measure used in twenty-first century should be more coherent and precise at least in their principles.

  14. Ezra Steinberg says:

    The post from gela@ effectively makes the point (as UKMA have often said) that the country needs to adopt and use a single coherent system of measurement (that is truly a system, namely, the SI.

    One can only imagine how much numeracy would improve in the UK if the metric muddle were finally resolved in favour of pure SI.

  15. derekp says:

    In the wake of the problems with the 787, resulting in the grounding of the whole fleet, the Guardian last week had this to say on outsourcing:

    'The technological leap was always likely to cause teething issues. But these were exacerbated by Boeing's decision to massively increase the percentage of parts it sourced from outside contractors. The wing tips were made in Korea, the cabin lighting in Germany, cargo doors in Sweden, escape slides in New Jersey, landing gear in France.

    The plan backfired. Outsourcing parts led to three years of delays. Parts didn't fit together properly. Shims used to bridge small parts weren't attached correctly. Many aircraft had to have their tails extensively reworked. The company ended up buying some suppliers, to take their business back in house. All new projects, especially ones as ambitious as the Dreamliner, face teething issues but the 787's woes continued to mount. Unions blame the company's reliance on outsourcing.

    Bill Dugovich, communications director at SPEEA, the professional aerospace union, said his members had first voiced their concerns in 2002. "Outsourcing in general lengthens supply lines, creates problems with language and culture and is extremely hard to coordinate. You have seen a plethora of problems at Boeing. Things get outsourced then they have to come back to Boeing to get fixed," he said.'

    The Guardian article does not comment on the outsourcing of pound-inch parts to metric companies, but reading between the lines of the article you can see that it could be part of the problem.

  16. John Frewen-Lord says:


    Indeed it is. The key sentence is: "Parts didn’t fit together properly." All parts need a tolerance of course, and it is assumed that tolerances will average out - some parts slightly greater than specified, some slightly less.

    The problems come when you, say, are drilling rivet holes specified in inch spacing on a machine that is dimensioned in metric units. You can come very close to the inch spacing (and within tolerance), but not exact. In this situation all the slight innacuracies, instead of averaging out, become cumulative, until by the last rivet you are lucky if the holes even begin to correspond with the holes in the part to be attached, which might have been machined on an inch-based tool. How Boeing didn't even see this coming boggles the mind, and makes me wonder at their level of technical competence (I say this slightly tounge-in-cheek, as next month I'm on BA 777s to Toronto and back).

    Latest reports show that Boeing will take at least 1100 787 sales just to break even (and some experts are saying it could be as high as 2000). Now compare Boeing's issues with how Airbus assembles aircraft. Many components, made in any number of different factories in many countries (all wings for example made in UK), shipped to Toulouse or wherever (Airbus now has prime assembly parts in Germany as as France), and all mating together perfectly. This can only be achieved when all players are using the same design language - metric. The first complete airframe for the A350 (Airbus answer to the 787) has been rolled out (six months behind schedule, but for reasons that are not measurement related, as was the case for the 787), and will fly later this year. The A350 was projected to be six years behind the 787 on entry into service - now it looks to be more like three.

    Even the giant A380 made its maiden flight more or less on schedule, its later manufactoring problems being more to do with incorrect assemby diagrams for the complex wiring harnesses between different modules, which then didn't mate up (but all were accurate according to the assembly diagram each module was built to, and the prime fuselage modules to which the harnesses were attached did mate perfectly).

    Will America (and especially Boeing) learn from this and convert to the world's standard measurement system, SI? Probably not. They seem to be a bit like the UK DfT and the country's road signs - head buried firmly in the sand, and don't let any facts get in the way of a flawed and stubborn philosophy.

  17. philh says:

    The last two comments from Derek and John raise an interesting point.

    The Unions are bound to argue against outsourcing because it threatens jobs for their members.

    So does that mean they will also oppose anything that makes it more viable technically? i.e. US metrication?

  18. John Steele says:


    More generally, unions have pretty much opposed metrication. In some industries, workers must provide their own tools, so this is partially understandable. One union that didn't oppose it much was the UAW. Automotive does not permit (moreless require) workers to bring tools into the plant; they must use company-provided tools.

    Small business owners generally oppose metrication too as they primarily see costs, not chances for increased profit. Most union members vote Democratic, most small business owners vote Republican. so neither party is too excited about embracing metrication. If we could just get the NRA excited about metrication, we'd be metric. Every politician listens to them.

  19. John Frewen-Lord says:


    I think Boeing will have to bite this bullet eventually, simply because all its future programs are/will be heavily dependent on sales in Japan - it has over 80% of the Japanese market (Japanese airlines were the first in the world to place orders for the 787), and Airbus barely gets a look-in. The quid pro quo for that is that something like 40% of the 787 comes from Japan. I can't see Boeing wanting to risk that level of market penetration by yanking manufacture back in-house. Even the unions should be able to see that. In which case, Boeing's measurement problems are not going to go away any time soon.


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