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Comment by adgjlsfhk1 | Hacker News Reader

Roughly 25 years. The other thing that you probably didn't notice directly but made you feel better is the better pressurization. Newer planes tend to keep higher pressures (since carbon fiber is ridiculously strong), which helps prevent some of the general discomfort of flying.

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NB, for any budding bathynauts: carbon fibre is strong under tension, which is precisely the use-case for higher-than-ambient-pressure vessels such as air- and space-craft.

It's far less comparatively strong under compression, which seems to have been the principle failure mode of the now-permanently-submerged Titan.

The failure modes of explosive vs. implosive failure are also relevant. High-pressure implosions tend to collapse the entire hull, whilst so far as I understand, explosive failure, particularly at the relatively low pressure differentials of air and space flight, tend to be localised, and the fibre-reinforced nature of composite materials should reduce damage to the neighbourhood of the initial failure point in many cases. Implosive failure needn't actually penetrate the hull so much as crease it, a mode which CF handles poorly respective to the application.

I think a lot of people have a misconception that keeping pressure in is just as hard as keeping pressure out, while in some ways, it's probably easier to make a space station (keep 1 ATM in) than to make a submarine (keep 500 ATM out.)

Hence sci-fi horrors is like getting sucked out into space through a pinhole.

yeah, this is really one of my pet peeves. Lots of people like to pretend that holding a vacuum is really hard, but if all you need is a gross vacuum, it's only about as hard as going down 40 ft into the water.

Other misconception: That we immediately die in space. You can probably survive a minute or two.

If a micrometeorite (or other space detritus) puts a pinhole in a wall in the space station, can you plug it by covering it with your finger, without necessarily losing the finger ?

IANASpaceDoctor, but very likely you can, at the possible expense of a space-hickey.

Most of you would still be at the right pressure, and skin is pretty tough stuff.

NGL my mind went straight to the Titan after I read "carbon fiber" and "ridiculously strong" in one sentence. Thank you for the clear explanation and for alleviating my anxiety of flying transcontinental again.

Carbon fibre, like most composites, is also very hard to predict. It's much more complex to model, especially in terms of how it ages, and there's a lot of opportunity for part-to-patt variability, so even extensive testing doesn't necessarily give you an all-clear. It took a lot fo time and money to get carbon fibre to the same level of understanding as metals for use in airlines.

I never got the chance to fly in a Dreamliner, but I have been told that its air is also more humid than standard jets (because of the carbon-fiber construction, I think, so metal oxidation isn’t an issue).

> because of the carbon-fiber construction

yes

> so metal oxidation isn’t an issue

no. It's not rust, but that higher pressure air can hold more water at the same relative humidity. The higher pressure air is achievable because carbon fiber has higher tensile strength per weight.

That makes more sense.

Thanks!

> higher pressure air can hold more water at the same relative humidity

The 787 and A350 cabins have higher relative humidity.

> no. It's not rust,

Citation needed. Corrosion resistance is one of the most advertised benefits of the composite materials in those aircraft[1][2].

1: http://www.lb.boeing.com/commercial/aeromagazine/articles/qt...

2: https://skybrary.aero/sites/default/files/bookshelf/3851.pdf

Nice, then finally I won't get nosebleeds on long flights <3

Also, I get headaches on planes. The 10,000-foot altitude air pressure does it.

Really, it's that low on a regular plane? I thought it was more like 6000ft equivalent or so. 10k is high, it's like a third of the altitude they actually fly at.

Edit: it's between 6000 and 8000: https://aviation.stackexchange.com/questions/66563/why-arent...

So around 8000 for the likes of the bog standard 737 and A320 and around 6000 for the cool new carbon fibre ones I guess.

May be right. I was told 10K, but that was probably a number that was rectally-sourced.

10k is the altitude above which oxygen masks are required, and any decompression above this altitude triggers the oxygen masks to drop and pilots to make an emergency decent back down to 10k ft.

The 787 and the A350 are both a delight to fly long haul

I still prefer A380 when I can get one. The extra space is amazing.

Isn't that determined by seat pitch, which in turn is arbitrarily configurable by the airline? What does the model have to do with it?

Given how huge the A380 is, it is more likely to fly less than completely full, which increases the odds that you'll have vacant seat(s) next to you in economy class.

Also, if you want to go for a walk, the distance you are allowed to walk is a lot further.

> Given how huge the A380 is, it is more likely to fly less than completely full

That is quite nice as a passenger, but also a big part of why they're no longer made, and why most airlines are phasing them out...

The A380 has higher ceilings than other planes. Doesn't help the knees but makes it feel a lot more airy.

One thing I dislike about flying a full-ish A380 is the length of time for meal service. It can be over 1 hour that you have to sit with your tray table occupied and seat upright, before your tray gets picked up. If you want to use a laptop or sleep, it feels like forever.

These are Boeings we're talking about.

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