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Another English/Metric "Spacecraft" Problem

Posted by Hemos on from the oh-the-joys-of-system-management dept.

SuperDry writes "There's been another spacecraft failure that's been attributed to an English/Metric units problem, this time at Tokyo Disneyland's Space Mountain. An axle broke on a "spacecraft" (a.k.a. roller coaster train) mid-ride, causing it to derail (nobody was hurt). The final investigation report has been released, and the root cause has been determined to be a part being the wrong size due to a conversion of the master plans in 1995 from English units to Metric units. In 2002, new axles were mistakenly ordered using the pre-1995 English specifications instead of the current Metric specifications. Apparently size does matter, even if it's only a 0.86mm difference."

7 of 748 comments (clear)

  1. Re:Who's at fault here, really? by agentZ · · Score: 4, Interesting

    So in other words it wasn't a metric/inches conversion problem, but rather just using the old blueprints instead of the current one?

  2. About time America left the stone age by GileadGreene · · Score: 5, Interesting
    Sigh. When is America going to ditch its archaic measurement system and use the same standard as everyone else? I work in the space industry, and I see this idiocy going on all the time: half the team works in metric, the other half in english. Most of the time everyone manages to keep it straight. But every now and then, a mistake happens. Scientists all use metric. Most engineers are trained in metric. Let's just switch to metric for everything and be done with it.

    A side note: in New Zealand (and possibly other Commonwealth countries - I haven't checked) they don't even refer to "English units". Their term is "Imperial units". Which tells you how long it's been since they made the switch...

  3. America versus the rest by Anonymous Coward · · Score: 5, Interesting

    Some things that would be nice to standardize (but will probably not happen in my lifetime)

    - imperial - metric
    - Letter paper - A4
    - Fahrenheit - Celcius
    - AM/PM - 24 hr notation
    - month/day/year - day/month/year

    Anything I left out?

  4. When will this stop? by photonic · · Score: 3, Interesting
    First of all i want to applaud the Japanese culture. The press report seems to originate from the company that made the error: A public statement about the how and why of the error, with apologies and even in english. I wish more companies were like that.

    This incident (although caused by a transition TO the metric system) leads us to the question how many more years until we finally get rid of the imperial system. The US standard bureau has a page that describes their effort in the conversion. They quote the metric conversion act of 1975, but i don't know how much has happened since then. How many years do I have to buy US stuff here in Europe that is half metric and half imperial? For god sake, even the UK has switched! Does anybody know a real time-table for the transition??

    Obligatory Pulp Fiction quote:


    Vincent:
    And you know what they call a Quarter Pounder with Cheese in Paris?
    Jules:
    They don't call it a Quarter Pounder with Cheese?
    Vincent:
    No, they got the metric system there, they wouldn't know what the fuck a Quarter Pounder is.
    Jules:
    And what'd they call it?
    Vincent:
    They call it Royale with Cheese.

    If you ever run into a imperial system freak ask him to calculate how many square inch there are in a square mile ... without blinking.
    --
    karma police: arrest this man, he talks in maths; he buzzes like a fridge, he's like a detuned radio. [radiohead]
  5. Re:Who's at fault here, really? by hoofie · · Score: 5, Interesting

    Actually you are wrong !!!

    In 1983 an Air Canada flight ran out of fuel mid-flight. Disaster was averted due to a long-enough disused runway being available.

    Its now know as the "Gimli Glider" named after the abandoned air-force base where it landed. It was luck that one of the pilots was a glider pilot. Apart from the complete-cock up, it showed some fantastic flying and emergency management.

  6. Karma Whoring Info Post by Aidtopia · · Score: 3, Interesting

    A friend of mine in college in the late 80's did an internship with Disney Imagineering. At the time, they were redrawing plans for several attractions that were to be copied almost exactly from California and Florida version for use in Euro Disney. There was great concern that the Imperial to metric round-off would be a problem. The contractor's union in France mandated that they only use metric units in the blueprints, which is reasonable. But if you're trying to duplicate a ride that was originally designed in Imperial units, you need to keep in mind quite a few significant digits when you're measuring. For example, a section of track in a given ride might be 10 feet in the US. In metric that's 3.048 m. Would the French contractors really measure to that precision? Or would they round off to 3.05 or event 3.0? They were concerned that roundoff might be systematic causing the errors to accumulate in one direction. This was a big concern, and there were debates over whether some rides needed to be redesigned in metric from the start and possibly give up economies of standardized parts.

    That this happened in Space Mountain is also interesting, because Space Mountain was the first rollercoaster to have ATIS (automated track inspection system). Since it was a tightly wound coaster in a confined space it was difficult to do visual inspections. ATIS uses two techniques to detect problems with the track. The rails are actually tubes and they're pressurized in sections. When small cracks start to develop, the pressure drop is detected. Sensors also time cars through different sections of the track. If there is a trend of cars slowing through a section over time, it indicates that the ties between the rails are starting to give. ATIS is so much better than visual inspections at detecting problems early that it's used on most modern roller coasters.

  7. Mixing paradigms by slim · · Score: 3, Interesting

    I can live with people insisting on using Imperial measures.

    What bugs me is when they then only halfway use the Imperial paradigm.

    Case in point: when the iPod Mini was announced, I went to the web page to check out the specs. 2" x 3.6". Not having any intuitive feel for what that might mean, I wandered around the office trying to borrow a ruler, and once I'd found one, started to draw an iPod-sized square on a piece of scrap paper.

    A 2" line across the bottom was easy. Then I set about drawing the vertical. 3", then another 6 gradations... oh, wait a minute, each inch is subdivided into 16ths. Tricky. Grab calculator.

    So please, either use mm, or go the whole hog and state 3 inches and (10/16)".