5 ms·

The cause analysis of how they ended up with half a tank of fuel is crazy. The crew loading the fuel mistook lbs for kg. The plane's fuel indicators were faul

The cause analysis of how they ended up with half a tank of fuel is crazy. The crew loading the fuel mistook lbs for kg. The plane's fuel indicators were faulty and required a manual procedure before takeoff. The engineer communicated that to a pilot and the pilot misunderstood. That pilot relayed his misunderstanding to the next pilot and that next pilot misunderstood the misunderstanding. And then that next pilot misunderstood the checklist indicating whether it was legal to fly with the non-functioning fuel gauge. And the flight engineer didn't catch the lbs/kg mistake. Then during a brief stopover in Ottawa, the captain thought to re-measure the fuel with the floatstick, but still used the incorrect conversion factor.

YeahSureWhyNot 8y ago
damn
eterm 8y ago
I wonder how many lives are lost each year (not just in aviation but globally) because the US refuses to convert to the metric system.
- hn_throwaway_99 8y ago
  Or spacecraft lost: https://en.m.wikipedia.org/wiki/Mars_Climate_Orbiter https://en.m.wikipedia.org/wiki/Mars_Climate_Orbiter
  - rzimmerman 8y ago
    The loss of MCO is actually a very interesting story about both engineering culture (engineers noticed a problem but the organization didn’t respond to investigate/fix it) and the conversion to metric. The root came from NASA deciding to use metric on this project and a contractor using the wrong units. But it’s the kind of thing that the process should be able to catch and handle. It bugs me to dismiss this failure as “haha why doesn’t NASA use metric” because not only is it a direct result of NASA switching to metric, there are really good engineering lessons that get ignored.
- microcolonel 8y ago
  > I wonder how many lives are lost each year (not just in aviation but globally) because the US refuses to convert to the metric system. Keep in mind that the U.S. is not the only place where measures are mixed. If anything, British people end up using more measures than Americans. Here in Canada, we have a lot of things read out in both, because of the immense sticking power of customary measures. U.S. organizations are actively encouraged and (for the most part) fully allowed to adopt SI measures, but it's not like switching road sides, where everything makes sense after you hear "drive on the right now". Keep in mind that powered flight was basically entirely developed by Americans and pre-SI Brits, and already had more than fifty years of history by the time either pioneering country adopted SI in any significant way. It should not surprise you in the slightest that an American plane expected to hear fuel mass given as weight in pounds; in fact, it should astonish you that anyone is trying to measure it in kilograms in North America.
  - eterm 8y ago
    I'm British, so you don't need to explain using mixed systems, however in any kind of academic, engineering or scientific contexts metric units are used almost exclusively. Yes, people still refer to height in feet and inches a lot, and we'll drink a pint (a real pint! None of your mini-pints!), but that does change over time. For example older people will use stone and pounds for their weight but being younger the doc doesn't bother telling me my weight in anything but kilograms so I don't even know my weight except in Kg. Even in Britain, in almost all engineering contexts, SI units would be assumed. Your point about Americans assuming imperial units is precisely wwhy it's so dangerous that metrification hasn't happened there. If the US went metric, then there would no longer be any need to assume anything but metric anywhere, and it would be safer for it. Yes, there's a long standing tradition, but it only takes a couple of generations to completely change, and that would likely be hastened by being the last large country to do so and having a large cultural footprint on the rest of the world. If the US did convert to metric, in 3 or 4 generations the whole world would be metric, and there wouldn't be any "wrong assumptions", and it is making bad assumptions that lead to preventable failures. If China can manage to go metric, the US can too.
    - 8y ago
- mertd 8y ago
  Lives would also be lost in the ensuing confusion if US were to switch to the metric system.
  - trothamel 8y ago
    Indeed. It's only due to the skill of the pilots that lives weren't lost during the Gimli Glider incident.
    - magduf 8y ago
      Only partially. Part of it was pure luck, that no one was on the track at that moment when the plane landed on it. There were people at the track at the time, doing races, but the plane just happened to come down at the right time.
dovetailcode 8y ago
Why don't they just ditch imperial measurements altogether? Also, that description sounds like tracing a bug through a few layers of software where there wasn't proper error handling along the way, just trusting the data being passed around.
- DuskStar 8y ago
  If I'm remembering correctly, they were in the process of switching from imperial to metric at the time.
- laken 8y ago
  Amusingly, the reason why the confusion was there was because at that time Canada was in the process of converting from the Imperial system to the Metric, but they had to manually convert some things still!
xvf22 8y ago
They ended up fixing it afterwards and it continued to fly with Air Canada until 2008 and it went up for auction in 2013[0]. [0] https://business.financialpost.com/transportation/air-canadas-old-gimli-glider-on-the-auction-block-sunday https://business.financialpost.com/transportation/air-canada...

YeahSureWhyNot 8y ago

damn

eterm 8y ago

I wonder how many lives are lost each year (not just in aviation but globally) because the US refuses to convert to the metric system.

hn_throwaway_99 8y ago
Or spacecraft lost: https://en.m.wikipedia.org/wiki/Mars_Climate_Orbiter https://en.m.wikipedia.org/wiki/Mars_Climate_Orbiter
- rzimmerman 8y ago
  The loss of MCO is actually a very interesting story about both engineering culture (engineers noticed a problem but the organization didn’t respond to investigate/fix it) and the conversion to metric. The root came from NASA deciding to use metric on this project and a contractor using the wrong units. But it’s the kind of thing that the process should be able to catch and handle. It bugs me to dismiss this failure as “haha why doesn’t NASA use metric” because not only is it a direct result of NASA switching to metric, there are really good engineering lessons that get ignored.
microcolonel 8y ago
> I wonder how many lives are lost each year (not just in aviation but globally) because the US refuses to convert to the metric system. Keep in mind that the U.S. is not the only place where measures are mixed. If anything, British people end up using more measures than Americans. Here in Canada, we have a lot of things read out in both, because of the immense sticking power of customary measures. U.S. organizations are actively encouraged and (for the most part) fully allowed to adopt SI measures, but it's not like switching road sides, where everything makes sense after you hear "drive on the right now". Keep in mind that powered flight was basically entirely developed by Americans and pre-SI Brits, and already had more than fifty years of history by the time either pioneering country adopted SI in any significant way. It should not surprise you in the slightest that an American plane expected to hear fuel mass given as weight in pounds; in fact, it should astonish you that anyone is trying to measure it in kilograms in North America.
- eterm 8y ago
  I'm British, so you don't need to explain using mixed systems, however in any kind of academic, engineering or scientific contexts metric units are used almost exclusively. Yes, people still refer to height in feet and inches a lot, and we'll drink a pint (a real pint! None of your mini-pints!), but that does change over time. For example older people will use stone and pounds for their weight but being younger the doc doesn't bother telling me my weight in anything but kilograms so I don't even know my weight except in Kg. Even in Britain, in almost all engineering contexts, SI units would be assumed. Your point about Americans assuming imperial units is precisely wwhy it's so dangerous that metrification hasn't happened there. If the US went metric, then there would no longer be any need to assume anything but metric anywhere, and it would be safer for it. Yes, there's a long standing tradition, but it only takes a couple of generations to completely change, and that would likely be hastened by being the last large country to do so and having a large cultural footprint on the rest of the world. If the US did convert to metric, in 3 or 4 generations the whole world would be metric, and there wouldn't be any "wrong assumptions", and it is making bad assumptions that lead to preventable failures. If China can manage to go metric, the US can too.
  - 8y ago
mertd 8y ago
Lives would also be lost in the ensuing confusion if US were to switch to the metric system.
- trothamel 8y ago
  Indeed. It's only due to the skill of the pilots that lives weren't lost during the Gimli Glider incident.
  - magduf 8y ago
    Only partially. Part of it was pure luck, that no one was on the track at that moment when the plane landed on it. There were people at the track at the time, doing races, but the plane just happened to come down at the right time.

dovetailcode 8y ago

Why don't they just ditch imperial measurements altogether? Also, that description sounds like tracing a bug through a few layers of software where there wasn't proper error handling along the way, just trusting the data being passed around.

DuskStar 8y ago
If I'm remembering correctly, they were in the process of switching from imperial to metric at the time.
laken 8y ago
Amusingly, the reason why the confusion was there was because at that time Canada was in the process of converting from the Imperial system to the Metric, but they had to manually convert some things still!

xvf22 8y ago

They ended up fixing it afterwards and it continued to fly with Air Canada until 2008 and it went up for auction in 2013[0]. [0] https://business.financialpost.com/transportation/air-canadas-old-gimli-glider-on-the-auction-block-sunday https://business.financialpost.com/transportation/air-canada...