4 ms·

Pressure altitude, they describe cabin pressure in terms of apparent altitude, usually 8000ft+/- and by lowering the outside altitude they can increase the inte

Pressure altitude, they describe cabin pressure in terms of apparent altitude, usually 8000ft+/- and by lowering the outside altitude they can increase the internal pressure/decrease apparent altitude.

sagebird 7y ago
I see what you are saying and the article's sentence is technically not wrong. But it is a useless phrasing none the less. By decreasing altitude they decrease apparent altitude... so what? How is that different than saying by filling a glass with water I increase apparent fill level... This is a medical situation so what is relevant is how the change effects the body. So I think the most clear thing to say is that... they flew lower to increase the cabin pressure. Maybe it is some thoughtless force of habit that they chose to describe it that way.
- AWildC182 7y ago
  Yea, the article was a little strange. They were trying to use the technical aviation terminology as much as possible but ended up mixing and matching a bit after apparently realizing explaining all of it would make the article really long.
- mbrameld 7y ago
  Pressure altitude isn't the same as flight altitude. You can decrease flight altitude dramatically without changing cabin pressure altitude. You can also vary cabin pressure altitude without changing flight altitude. So saying they descended to lower the cabin pressure altitude is not useless. It describes the outcome (lower cabin pressure altitude) and how they achieved it (by descending). There are other ways of changing cabin pressure altitude, and there are reasons to descend other than for the purpose of lowering cabin pressure altitude. Edit: I see the "I don't understand this so it must be bad" reaction in a lot of junior devs. It's interesting to see it show up in other areas!
  - sagebird 7y ago
    There is value in adding a concise, incorrect comment on hacker news if it is presented in a clear and falsifiable way. I am sorry I did not google "pressure altitude" before commenting and did not present my findings so others could learn from it, but I am happy that AWildC182 cleared it up for me. I still think that the sentence in the article could be written in a clearer, and more direct and correct manner -- that is I think it is bad for reasons other than me not understanding the definition. I understand that pressure altitude is a way to express pressure using a theoretical equivalent altitude, and that it is widely used in aviation because it is convenient and tangible way to express pressure! Though, I still think the goal was to increase pressure (measured in Atmospheres) on the person undergoing a medical emergency. There would be almost no point for a space pilot to descend from 70 to 65 miles altitude in contrast to a terrestrial pilot descending from 8 miles to 3 miles. Even though the difference is pressure altitudes is the same (5 miles delta), the difference in Atmospheres is hugely different. (In the space case there is almost no difference because there is almost no pressure!) That indicates that the patient requires an increase is pressure (Atmospheres) So why not write "They descended to increase cabin pressure". It's simpler, more direct, and shorter. It's offensive to couch a personal insult as an "interesting observation" about junior devs' failings showing up in other areas. Your whole comment seems to be made in bad faith and attempts frame me as a fool to be laughed at. This is one of the reasons I sometimes hate participating in hacker news. Even if I'm an idiot I don't think the snark is justified.
    - scarejunba 7y ago
      You got two pieces of advice for the price of one. In your place, I'd be thankful. No one will remember your username on the internet. I haven't even seen it. Unlike real life, any feeling of humiliation can easily be ignored.
    - mbrameld 7y ago
      You initially expressed confusion about the difference between altitude and pressure altitude with your question "Doesn't flying lower make the cabin pressure increase?" When AWildC182 pointed out your mistake you insisted that the sentence was useless because it was confusing to you. The sentence seems useless to you because you don't have the depth of knowledge to understand it, and instead of putting forth the effort to understand you throw up your hands and declare it a bad sentence. That pattern happens all the time in software with junior developers. They come in so sure of their abilities that anything they don't understand must be wrong or bad or useless. Your exchange here was the first time I had seen it happen outside of software development and I thought it was interesting, so I commented on it. If you find it insulting to have that behavior pointed out to you I would suggest avoiding the behavior.

sagebird 7y ago

I see what you are saying and the article's sentence is technically not wrong. But it is a useless phrasing none the less. By decreasing altitude they decrease apparent altitude... so what? How is that different than saying by filling a glass with water I increase apparent fill level... This is a medical situation so what is relevant is how the change effects the body. So I think the most clear thing to say is that... they flew lower to increase the cabin pressure. Maybe it is some thoughtless force of habit that they chose to describe it that way.

AWildC182 7y ago
Yea, the article was a little strange. They were trying to use the technical aviation terminology as much as possible but ended up mixing and matching a bit after apparently realizing explaining all of it would make the article really long.
mbrameld 7y ago
Pressure altitude isn't the same as flight altitude. You can decrease flight altitude dramatically without changing cabin pressure altitude. You can also vary cabin pressure altitude without changing flight altitude. So saying they descended to lower the cabin pressure altitude is not useless. It describes the outcome (lower cabin pressure altitude) and how they achieved it (by descending). There are other ways of changing cabin pressure altitude, and there are reasons to descend other than for the purpose of lowering cabin pressure altitude. Edit: I see the "I don't understand this so it must be bad" reaction in a lot of junior devs. It's interesting to see it show up in other areas!
- sagebird 7y ago
  There is value in adding a concise, incorrect comment on hacker news if it is presented in a clear and falsifiable way. I am sorry I did not google "pressure altitude" before commenting and did not present my findings so others could learn from it, but I am happy that AWildC182 cleared it up for me. I still think that the sentence in the article could be written in a clearer, and more direct and correct manner -- that is I think it is bad for reasons other than me not understanding the definition. I understand that pressure altitude is a way to express pressure using a theoretical equivalent altitude, and that it is widely used in aviation because it is convenient and tangible way to express pressure! Though, I still think the goal was to increase pressure (measured in Atmospheres) on the person undergoing a medical emergency. There would be almost no point for a space pilot to descend from 70 to 65 miles altitude in contrast to a terrestrial pilot descending from 8 miles to 3 miles. Even though the difference is pressure altitudes is the same (5 miles delta), the difference in Atmospheres is hugely different. (In the space case there is almost no difference because there is almost no pressure!) That indicates that the patient requires an increase is pressure (Atmospheres) So why not write "They descended to increase cabin pressure". It's simpler, more direct, and shorter. It's offensive to couch a personal insult as an "interesting observation" about junior devs' failings showing up in other areas. Your whole comment seems to be made in bad faith and attempts frame me as a fool to be laughed at. This is one of the reasons I sometimes hate participating in hacker news. Even if I'm an idiot I don't think the snark is justified.
  - scarejunba 7y ago
    You got two pieces of advice for the price of one. In your place, I'd be thankful. No one will remember your username on the internet. I haven't even seen it. Unlike real life, any feeling of humiliation can easily be ignored.
  - mbrameld 7y ago
    You initially expressed confusion about the difference between altitude and pressure altitude with your question "Doesn't flying lower make the cabin pressure increase?" When AWildC182 pointed out your mistake you insisted that the sentence was useless because it was confusing to you. The sentence seems useless to you because you don't have the depth of knowledge to understand it, and instead of putting forth the effort to understand you throw up your hands and declare it a bad sentence. That pattern happens all the time in software with junior developers. They come in so sure of their abilities that anything they don't understand must be wrong or bad or useless. Your exchange here was the first time I had seen it happen outside of software development and I thought it was interesting, so I commented on it. If you find it insulting to have that behavior pointed out to you I would suggest avoiding the behavior.