English/metric measurement error in the Mars Climate Orbiter

[mklotz]

...
I can measure in both and have both to measure with. I have a great number of precision measuring tools that belonged to my father. Some from the 1930's. I learned a lot from him and miss him a lot. Someone suggesting that I throw them out, even if I do respect the person, is not going to sit well with me.

Let's all use the system we are comfortable with and not criticize. Nothing we say here is going to change the fact there is more than one measuring system.

An extract from my broadside on discussing measurement systems...

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An insidious so-called argument to avoid is the exceedingly narrow-minded idea that only the aspect of a measurement system you personally use is a proper basis for deciding which measurement system is best for the society at large. It goes something like this...

I don't need another system to machine my parts. The difference between inferial* and metric is just a factor of 25.4, why bother changing; I can make accurate parts using my present inferial system.

There might be some validity to this approach IF THE JOB OF EVERYONE IN THE SOCIETY INVOLVED NOTHING MORE THAN MAKING LINEAR MEASUREMENTS. People have many jobs involving all the aspects of the measurement system. Using one that's antiquated, un-necessarily complex and confusing leads to inefficiency, lost time and dangerous mistakes.

Another so-called argument I've heard goes something like this: What's so great about metric; there are lots of ways of measuring things. While that's true, if you design your alternate system to incorporate the advantages listed at the beginning of this treatise, you will have a system remarkably similar to the metric system. The standards for length, mass, etc. might be different but, as we've seen, the size of the standards are irrelevant; it's how those standards are subdivided and related that makes the system practical and efficient to use. So why create a system that's very similar to the existing metric system? The existing system is already in use in most of the civilized world and there are real advantages to using an existing system.

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An older copy of the broadside itself can be found here...

A glimmer of hope

I can supply the most current version if requested.

I suppose a succinct warning might be something like...

Don't use any form of transportation that's being maintained in a country that professes to understand and use two different measurement systems.

[Philip Davies]

Of course, an 11 inch ruler would allow them to calculate circumference.

[mklotz]

Just in case you still think it's reasonable to have two or more measurement systems in use at the same time, take a look at these examples...

https://www.conantphysics.com/wp-con...easurement.pdf

Most distressing is this quote...

Note that aircraft altitudes are in feet throughout the world, except for China, Mongolia, and the CIS (former Soviet states), which use meters.

Think about what happens if some already metric nation decides to follow China's lead. How do you guarantee that the notification of the switchover reaches all the people who need to know about it? How do you guarantee these people, once informed, take all the necessary actions in response to the changeover?

I believe most aircraft autopilots currently accept inputs in feet. (Correct me if I'm wrong on that.) Does that mean that, if the pilot is assigned a flight level in meters, he must make a conversion to feet before adjusting the autopilot? Sounds like a recipe for disaster to me.