Preliminary report into Air India crash released • Hacker News Board

Re: Preliminary report into Air India crash released

#841

Post by foldr » Sun, Jul 13, 2025, 11:26 AM UTC

ahartmetz wrote: post #836

foldr wrote: post #702

Earlier quoted context omitted.

I don’t think there’s much connection between a plane’s ability to do a sideslip and how well it glides. A sideslip is just what naturally happens if you apply opposite aileron and rudder inputs. I think the issue is just that it’s a rather acrobatic maneuver to perform in a large passenger jet.

Since a sideslip increses air resistance by essentially flying sideways, if I didn't know that it has been done, I'd say it might even break apart a (long, thin) plane that wasn't designed for it. And it still might, but at much higher speeds than close to landing.

It's not unheard of for airliners to use a sideslip when landing in a crosswind, so I don't think structural strength is likely to be an issue at landing speeds.

https://code7700.com/pdfs/bca/bca_cross_with_care_2015-06.pd...

Re: Preliminary report into Air India crash released

#842

Post by tomhow » Sun, Jul 13, 2025, 11:28 AM UTC

sdgsdgssdg wrote: post #249

zahlman wrote: post #159

Earlier quoted context omitted.

This is a place that puts "Hacker" in the name despite the stigma in the mainstream. Given the intended meaning of the term, I would naturally expect this to be a place where people can speculate and reason from first principles, on the information available to them, in search of some kind of insight, without being shamed for it. You don't have to like that culture and you also don't have to participate in it. Making…

(Different user here) Hacker News' "culture" is one of VC tech bros trying to identify monopolies to exploit, presumably so they can be buried with all their money when they die. There's less critical thinking here than you'd find in comments sections for major newspapers.

This is false, and if this stereotype was ever based in anything real, that era ended in the early 2010s.

The modal HN reader now is a tech employee or freelancer.

Re: Preliminary report into Air India crash released

#843

Post by manquer » Sun, Jul 13, 2025, 11:30 AM UTC

agubelu wrote: post #829

manquer wrote: post #775

Earlier quoted context omitted.

All we know is the pilot flying is only asking whether the pilot monitoring if he cut off - We don't know if he meant the switch specifically at all. He could also have meant engines or thrust in general. There are many other visual signals and UX indicators to know if engines are spinning down. Thrust levels, to RPM to falling speed, change in angle of attack, rate of climb, even engine noise, vibrations you expect…

I think there are a couple of factors that disprove these theories: - The specific mention of "cut off" in the CVR is very telling. If both pilots were genuinely surprised, you'd expect they'd say something like "engine failure" or "loss of thrust" first. Noone thinks the engines have been shut down as a knee-jerk reaction to a sudden loss of thrust. - If investigators had the slightest indication there's a software…

> an emergency airworthiness directive would have been issued by now. This hasn't happened.

737 Max incidents proved it isn’t always the case.

This is also not the NTSB or FAA doing direct investigation . Without certainty no one is issuing a directive, at this stage it is simply too early and only a possibility

I wouldn’t read so much intent during high stress part of takeoff from two non native speakers

Re: Preliminary report into Air India crash released

#844

Post by tomhow » Sun, Jul 13, 2025, 11:33 AM UTC

dale_huevo wrote: post #322

sdgsdgssdg wrote: post #249

Earlier quoted context omitted.

(Different user here) Hacker News' "culture" is one of VC tech bros trying to identify monopolies to exploit, presumably so they can be buried with all their money when they die. There's less critical thinking here than you'd find in comments sections for major newspapers.

[flagged]

Please don't sneer, including at the rest of the community.

https://news.ycombinator.com/newsguidelines.html

Re: Preliminary report into Air India crash released

#845

Post by tomhow » Sun, Jul 13, 2025, 11:33 AM UTC

aerospace83 wrote: post #132

xenadu02 wrote: post #40

Earlier quoted context omitted.

It could be defective switch springs, fatigue-induced muscle memory error, or something else. The pilot who did it saying he did not may not have realized what he did. It's pretty common under high workload when you flip the wrong switch or move a control the wrong way to think that you did what you intended to do, not what you actually did. That said Boeing could take a page out of the Garmin GI275. When power is re…

[flagged]

Please don't sneer, including at the rest of the community.

https://news.ycombinator.com/newsguidelines.html

Re: Preliminary report into Air India crash released

#846

Post by wkat4242 » Sun, Jul 13, 2025, 11:50 AM UTC

foldr wrote: post #702

kalenx wrote: post #651

Earlier quoted context omitted.

Yes. On a plane which is designed to be a good glider. I highly doubt a 767 is designed to be a glider. It's definitely not impossible (after all, it was done successfully!), but certainly a very difficult (and undocumented) one on such a plane.

I don’t think there’s much connection between a plane’s ability to do a sideslip and how well it glides. A sideslip is just what naturally happens if you apply opposite aileron and rudder inputs. I think the issue is just that it’s a rather acrobatic maneuver to perform in a large passenger jet.

Yes an airliner is not designed for it and could easily get into a deadly spin when doing it. Especially engines out because you have two huge surfaces blocking airflow. A glider can do it pretty naturally because of its extremely low stall speed.

But I wouldn't call it impossible that's all.

Re: Preliminary report into Air India crash released

#847

Post by xz0r » Sun, Jul 13, 2025, 12:42 PM UTC

yason wrote: post #672

It is known that the switches cannot effectively be flipped by accident. It is known that the switches were set to "cut-off" because they were then later restored to "run", so it was not an electrical fault (i.e. switches pointing to run but reporting cut-off). Pilot dialogue and engine telemetry confirms the cause of power loss was fuel cut-off. The question I can't help but think is how did the pilot realize it was…

> how did the pilot realize it was the cut-off switches?

The answer to this question is explained by a pilot in here https://youtu.be/00ooqCuRoU8?t=731

The pilots can hear engines spool down.

Re: Preliminary report into Air India crash released

#848

Post by agubelu » Sun, Jul 13, 2025, 12:43 PM UTC

manquer wrote: post #843

agubelu wrote: post #829

Earlier quoted context omitted.

I think there are a couple of factors that disprove these theories: - The specific mention of "cut off" in the CVR is very telling. If both pilots were genuinely surprised, you'd expect they'd say something like "engine failure" or "loss of thrust" first. Noone thinks the engines have been shut down as a knee-jerk reaction to a sudden loss of thrust. - If investigators had the slightest indication there's a software…

> an emergency airworthiness directive would have been issued by now. This hasn't happened. 737 Max incidents proved it isn’t always the case. This is also not the NTSB or FAA doing direct investigation . Without certainty no one is issuing a directive, at this stage it is simply too early and only a possibility I wouldn’t read so much intent during high stress part of takeoff from two non native speakers

> 737 Max incidents proved it isn’t always the case.

> This is also not the NTSB or FAA doing direct investigation . Without certainty no one is issuing a directive, at this stage it is simply too early and only a possibility

You are mistaken. The first MAX crash resulted in emergency directives being issued barely a week after the crash. That investigation was conducted by the Indonesian authorities, not US ones.

Emergency directives aren't issued when there's complete certainty, quite the opposite. Hence the "emergency" bit.

> I wouldn’t read so much intent during high stress part of takeoff from two non native speakers

I agree there's some fuzziness since the exact transcription wasn't provided. But "why did you cut out the engines" is by no means a normal question when facing sudden thrust loss.

Re: Preliminary report into Air India crash released

#849

Post by wkat4242 » Sun, Jul 13, 2025, 1:15 PM UTC

shash wrote: post #581

wkat4242 wrote: post #570

Why didn't they turn them back on then? Or does it take too long to spin up again even if they are still spooling down? This is one of the worst possible moments for this to happen of course. Low speed, low altitude, lots of drag...

They did, about 10 seconds later (which is both incredibly short and an eternity). But the engines almost immediately start losing thrust and it takes them much more time to restart. At the end of the flight, FDR records that one engine was gaining thrust, and the other was attempting to spin up, but it was too late and they didn't have enough glide time for both to gain enough thrust to climb.

Yeah 30 seconds is not much. This is really the worst phase of flight for this to happen. 30 seconds later and the plane would have had much more altitude and energy

Re: Preliminary report into Air India crash released

#850

Post by anton-c » Sun, Jul 13, 2025, 1:31 PM UTC

lambdaone wrote: post #632

anton-c wrote: post #612

Earlier quoted context omitted.

Yes I acknowledge this. But I also retain control to the very last moment. I don't have to bank on the driver of my vehicle not being suicidal. If I feel another driver is dangerous, I can just stop. This obviously doesnt prevent all accidents but I've never been in a serious one. That being said ive flown plenty of times. My fear comes from lacking any control and just finding out mid-flight were going down through…

You still have to rely on other drivers not being actually suicidal. Just to give one terrifying example scenario: you will pass hundreds, if not thousands of other drivers driving in the opposite direction in the course of a long journey. Any motorist driving in the opposing lane has the ability to engage other drivers in a head-on collision at any time by making a relatively trivial maneuver. Given human reaction t…

This is all true. It doesn't really apply to my personal driving situation where I can't recall the last time I personally was on a road with a speed limit above 40. I drive less than half the days a week. Thats part of maintaining control for me. I can't set plane schedules. I can drive when there's less drivers and on slow roads.

Also, there are numerous situations you're leaving out where just stopping(or just slowing down) does solve the safety issue. Far more than a suicidal driver choosing me as their target.