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Preliminary report into Air India crash released
241–250 of 924 posts
Re: Preliminary report into Air India crash released
#242Earlier quoted context omitted.
Does the Flight Data Recorder consider the physical position of the fuel switches or does it get the information from some fly-by-wire part that could be buggy? The conversation would suggest that the switches were in CUTOFF position, but there is also a display that summarizes the engine status. There is no conversation that mentions flipping the switch to RUN again. EDIT: Why is there no Cockpit Video Recorder? The…
Airlines are decades behind on tech. You can get satellite internet almost anywhere on the planet and GPS can give you ten-foot accurate positioning, but we've still _lost_ planes because we haven't mandated a system that sends the realtime position of the plane over the satellite internet. The days of limited storage are still going strong in the industry.
There are reasons they don’t. This is a deceptively difficult problem
Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations)
And by stations, I mean aircraft. There are a TON. Current constellations probably wouldn’t even be able to handle half the current aircraft transmitting all at once. Bandwidth, in the physical sense, becomes a limiting factor
Coverage (different constellations have different coverage, which means planes would not have transmit guarantees depending on flight path). So you’d have huge gaps anyways
There have been alternative solutions posed, some of which are advancing forward. For example, GPS aware ELTs that only transmit below certain altitudes. But even that has flaws
Anyways I think we’ll see it in the next decade or two, but don’t hold your breath
Re: Preliminary report into Air India crash released
#243> The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off. So the fuel supply was cut off intentionally. The swi…
https://ad.easa.europa.eu/ad/NM-18-33 well hold your horses there... from the FAA in their 2019 report linked above: > The Boeing Company (Boeing) received reports from operators of Model 737 airplanes that the fuel control switches were installed with the locking feature disengaged. The fuel control switches (or engine start switches) are installed on the control stand in the flight deck and used by the pilot to sup…
What is "01 second" as quoted above? If it's 1 second, you could possibly conclude that it was intentional. If it's 0.1 second you might think it was an accident and the lock was disengaged.
Re: Preliminary report into Air India crash released
#244Earlier quoted context omitted.
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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…
For me it's mainly about intent/unearned confidence.
If someone is speculating about how such a problem might be solved while not trying to conceal their lack of direct experience, I'm fine with it, but not everyone is.
If someone is accusing the designers of being idiots, with the fix "obvious" because reasons, well, yeah, that's unhelpful.
Re: Preliminary report into Air India crash released
#245it makes sense to me that the pilot who said "I did not do it" actually did do it without realizing it, was supposed to be putting the landing gear up when he committed a muscle memory mistake. it happened around the time the landing gear should be up, and this explanation matches what was said in the cockpit, and the fact that the landing gear wasn't retracted. I think this idea was even floated initially by the you…
The landing gear lever is rather prominently featured in the 787 in a panel central to the cockpit layout so that either pilot can easily reach it. For decades and across many manufacturers, the landing gear lever has traditionally featured a knob that deliberately resembles an airplane wheel. It's very hard to mistake it for anything else. It's actuated by simply moving it up or down. The fuel control switches are b…
> This idea strikes me as even more unlikely than someone shifting their moving vehicle into reverse while intending to activate the window wipers.
I suspect you've never driven an older vehicle with the shifter on the steering column.
Re: Preliminary report into Air India crash released
#246Earlier quoted context omitted.
https://www.youtube.com/live/SE0BetkXsLg?si=LPss_su3PVTAqGCO Both of these extremely-experienced pilots say that there was near zero chance that the fuel switches were unintentionally moved. They were switched off within one second of each other, which rules out most failure scenarios. If it was an issue with the switches, we also would have seen an air worthiness directive being issued. But they didn’t, because this…
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260 souls is well into the territory of horrible terror attacks. By comparison, only 14 people died from the sarin gas attacks on the Tokyo subway.
Re: Preliminary report into Air India crash released
#247Earlier quoted context omitted.
But why does the pilot then comment that they are in the CUTTOF position and move it to RUN? A mechanical failure would have to also move the physical switch in the cockpit for the audio recording to make sence.
You have the exact CVR audio? The report says "one of the pilots is heard asking the other why did he cutoff" which I interpreted to mean one of them noticed the engines shutting down, and asked the other if he did that.
Then he would have asked the other pilot why the engines are shutting down. It seems a lot more probable that he glanced at the switches before asking such an explicit question.
Re: Preliminary report into Air India crash released
#248Earlier quoted context omitted.
> That doesn't necessarily mean that either of the two pilots activated them It does: 1. Those switches have physical interlocks and cannot be manipulated by any computer system. 2. The flight data recorder is measuring the position of the switches; they aren't inferring the position from some system state. There's a "position of this switch" channel. The switches were physically moved in the cockpit, that's basicall…
No, lacking other evidence (e.g. CVR recording) it doesn't mean they have been moved. The wiring in between the switches and the engine+FDR could've also developed an intermittent fault. The fact that your car's engine stops doesn't mean you turned the ignition switch off. Anyone who has had to troubleshoot a car with intermitent electrical faults knows that.
We have other evidence - the crew noticed, and then moved them back to the Run position, and the engines responded as you’d expect.
The switches physically moved, and there is no motor to actuate them without physical intervention.
Re: Preliminary report into Air India crash released
#249Earlier quoted context omitted.
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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.
Re: Preliminary report into Air India crash released
#250Earlier quoted context omitted.
Thanks for looking. I worked for Boeing (satellites, not airplanes) for a good part of my career, and I was there when Dennis Muilenburg pushed through his cost saving measures. It was the same culture that created the problems with the 737-MAX. Experienced design engineers were replaced/outsourced and the culture of safety was sacrificed. One example here: https://www.cnn.com/2019/04/30/politics/boeing-sensor-737-ma…
In that case, it could be true both that neither pilot manipulated the switch and that the system recorded a dual fuel cutoff.
Then why do we see the pilots notice the cutoff, move the switches back, and the engines respond as expected? The switched cannot move themselves. We’d expect to hear more commentary and confusion if the cutoff was active and the switches still in Run.