Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Air India flight to London crashes in Ahmedabad with more than 240 onboard

theguardian.com

Post reply on HN
Print view View original

271–280 of 633 posts

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#271

Post by lxgr »

roywiggins wrote: post #262
nindalf wrote: post #205

Earlier quoted context omitted.

Pro tip from an absolute rando: don’t bother with any source of breaking news. Read a weekly paper that summarises the important stuff. If something is truly pressing, you’ll hear about it from friends or coworkers.

Unfortunately for everyone's brains, this turned out to basically not be true with COVID- only real news fans (or people with expertise in the relevant science, but there are way less of those) were remotely aware that offices probably weren't going to be closed for only two weeks[0]. If you followed the news closely you stocked up on toilet paper when there were runs on it in Hong Kong, before there were runs on it…

If nobody followed the news or social media, there wouldn’t have been runs on toilet paper to begin with, as there never was a shortage to begin with and it was all just mass hysteria.

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#272

Post by JumpCrisscross »

aipatselarom wrote: post #160
JumpCrisscross wrote: post #151

Earlier quoted context omitted.

> was wondering what if current plane designs had 4 smaller but equally as efficient engines instead of 2 Impossible to answer until we know the cause. If it was independent powerplant failures, then yes. If it was e.g. fuel contamination, pilots improperly shutting down the engine, some other crap failing, then no. Speaking as someone with aerospace engineering and GA pilot experience.

>if this was a bird strike incident on both engines that maybe having 4 engines [...] It's pretty clear what the guy is inquiring about. Speaking as someone without aerospace engineering or GA pilot experience. My only relevant experience here is being able to read.

> My only relevant experience here is being able to read

Double bird strikes are “independent powerplant failures.”

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#273

Post by JumpCrisscross »

notahacker wrote: post #249
JumpCrisscross wrote: post #151

Earlier quoted context omitted.

> was wondering what if current plane designs had 4 smaller but equally as efficient engines instead of 2 Impossible to answer until we know the cause. If it was independent powerplant failures, then yes. If it was e.g. fuel contamination, pilots improperly shutting down the engine, some other crap failing, then no. Speaking as someone with aerospace engineering and GA pilot experience.

Current speculation around the raising of flaps suggests that independent engine failures weren't the cause. Proper investigation with access to better data than grainy video will tell us if that is the case and why. "4 smaller but equally efficient engines" feels like a unicorn though (we'll probably get to the point in future where four large engines are superior in efficiency to two of today's engines, but two lar…

> "4 smaller but equally efficient engines" feels like a unicorn

With turbines, yes, for fundamental reasons. With electric motors, on the other hand, perhaps not, though not particularly relevant to a long-haul route like AMD-LON.

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#274

Post by 542354234235 »

mattbrewsbytes wrote: post #137
aipatselarom wrote: post #112

Earlier quoted context omitted.

The guy's just asking if four engines instead of two would have made a difference? It's curiosity, it's learning, it's looking for an explanation. That's exactly the kind of comment that deserves to be here. >[...] who doesn't have any relevant expertise, Is that a requirement to comment on this thread? Do you fulfill that requirement you brought in?

That is entirely where I'm coming from - plane designs from the past had longer wingspans and supported 4 engines. Engines have gotten more efficient and powerful so cross-ocean routes don't need 4 engines anymore. So I was wondering what if current plane designs had 4 smaller but equally as efficient engines instead of 2. The vast majority of airplane accidents happen at takeoff or landings, if some of those can be…

>4 smaller but equally as efficient engines

Larger jet engines are more fuel efficient than smaller ones, because larger diameters allow for more bypass air and therefore more fuel efficiency [1]. It is a function of size and a lot of the engineering goes into materials and designs to be able to increase size and maintain strength. So you simply can't make 4 engines that are as efficient as 2 large ones, and that is compounded by the significant additional weight (and drag) of the duplicated engine parts and mounting structures.

>if some of those can be avoided by having 4 engines for commercial aircraft, its a worthwhile idea to explore

Everything comes with tradeoffs. Adding more engines mean more complexity, more maintenance, more chance of single engine failures, etc. You don't want to introduce more failure modes than what you are trying to fix. The move to two engines for large aircraft and the evolution of ETOPS (Extended Twin-engine Operational Performance Standards) involved a lot of people considering a lot of scenarios. I can guarantee the "why not 4 engines" question has been studied extensively.

[1] https://simpleflying.com/why-do-jet-engines-keep-getting-lar...

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#275

Post by xdennis »

jen729w wrote: post #116
blitzar wrote: post #102

Earlier quoted context omitted.

Pro tip from a lifelong life enthusiast: if its breaking news, wait one week - first-week speculation isn’t just unproductive, it’s often counterproductive. Flick through last weeks newspaper if you need reassurance.

Just read The Economist. Only comes out weekly!

I used to do that too, but the Rittenhouse incident was the final straw for me. I remember reading in the magazine that he "shot into the crowd", but by that point I had already watched the video analysis on the New York Times's YouTube channel which showed that he only shot at people who attacked him. That was what the jury agreed with as well.

In the end, I think the most accurate place to get your news from is a history book.

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#276

Post by potato3732842 »

ajross wrote: post #76
mattbrewsbytes wrote: post #63

Earlier quoted context omitted.

I was just watching something the other day about how jet engines have gotten more efficient and powerful over the last 50 years where commercial airliners really only need 2 engines. All 2 engine aircraft also have to be able to operate on 1 engine as well if there is a failure. One has to wonder if this was a bird strike incident on both engines that maybe having 4 engines would have allowed the plane to circle bac…

I don't think there's ever been a double-bird-strike incident, though. And what dual engine failures I can think of are due to failure of a shared system (e.g. fuel exhaustion, c.f. Gimli Glider). [Edit: yeah, yeah, forgot the Tom Hanks movie, sue me. I do wish folks would respond to the much more important point below, which isn't invalidated by a single data point though.] Constructing solutions for multiple-mode f…

>Constructing solutions for multiple-mode failures like this is a bad engineering smell. Almost always the solution isn't actually helping anything

Selection bias

The lower the barrier to entry of the subject matter the lower quality the people discussing it. This crap is like the Kardashians for white nerds with stem degrees.

The people with the requisite dozen brain cells to common sense realize these problems are complex and keep their mouths shut.

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#277

Post by roywiggins »

lxgr wrote: post #271
roywiggins wrote: post #262

Earlier quoted context omitted.

Unfortunately for everyone's brains, this turned out to basically not be true with COVID- only real news fans (or people with expertise in the relevant science, but there are way less of those) were remotely aware that offices probably weren't going to be closed for only two weeks[0]. If you followed the news closely you stocked up on toilet paper when there were runs on it in Hong Kong, before there were runs on it…

If nobody followed the news or social media, there wouldn’t have been runs on toilet paper to begin with, as there never was a shortage to begin with and it was all just mass hysteria.

It was never clear to me, but at least part of it was supposedly due to everyone pooping at home using consumer TP instead of at the office, using commercially packaged TP (two-ply, giant rolls for big dispensers). And that sudden shift started to empty shelves. If people had stocked up over a period of time, the empty-shelves situation that produced the fear probably wouldn't have happened.

Of course in practice there really was plenty of it to go around, dollar stores seemed to be the most flexible at navigating the supply chain derangement and if you didn't mind buying it by the roll, it was never really hard to find.

Also- you don't need to follow the news for there to be a panic, empty shelves will do that all on their own. Everyone deciding to stock up a little on everything was enough to deplete shelves, people walking in after saw empty shelves and stocked up more, etc. I don't think most people were following the "omg supply chain" news, they just saw depleted shelves.

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#278

Post by speakfreely »

Larrikin wrote: post #244
sofixa wrote: post #194

Earlier quoted context omitted.

> most planes can't dump fuel anymore. if it's a serious enough emergency you land overweight. When fuel is dumped, it's at high altitude where it just evaporates. Short haul jets can't do it, but their max takeoff weight is around their max landing weight, so it's fine. For long haul, it's not the same.

Are both opposing replies just wild speculation from two educated software engineers that don't actually know anything on the topic?

No one overestimates themselves in other knowledge domains quite like software engineers... with the possible exception of medical doctors.

Re: Air India flight to London crashes in Ahmedabad with more than 240 onboard

#279

Post by yohannparis »

jen729w wrote: post #116
blitzar wrote: post #102

Earlier quoted context omitted.

Pro tip from a lifelong life enthusiast: if its breaking news, wait one week - first-week speculation isn’t just unproductive, it’s often counterproductive. Flick through last weeks newspaper if you need reassurance.

Just read The Economist. Only comes out weekly!

Yep, I subscribe to the Le Monde weekly, 10 printed pages newspaper delivered home. Enough to know what's what and done.
Post reply on HN