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Comment by JanSolo | Hacker News Reader

Not really a huge surprise given that the debris was confirmed as a 777 flaperon a few days ago. However, It does mean that the Inmarsat positional analysis about the final location of the plane is likely correct. This should give a bit of confidence to the sailors who are running the naval search operation in the indian ocean. They were never quite sure that they were looking in the right place. I suspect their lack-of-results must be quite demoralising for them.

It also discounts some of the nuttier theories such as the plane landing in Russia or Afghanistan.

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The satellite position analysis only says where the plane likely was near the end of its flight. How it ended up in the water matters greatly. For example if there was someone conscious in the cockpit then it could have glided way outside of the search area. Even an uncontrolled spiralling into the ocean describes a potentially large area.

One thing that keeps resurfacing is that the whole affair is unlike anything before. Suicidal pilots have crashed quickly in all other cases, various things have involved extraordinary good luck or extraordinary knowledge (eg avoiding various radar coverage), explanations for satellite systems going offline/online require precise fiddling with various electrical busses, there aren't any credible explanations for deliberate act or accident, the Malaysian government has either covered things up or is very incompetent (or both), and it goes on.

Air France 440 was also shrouded in mystery (but nowhere near this degree), and turned out to be very poor airmanship by one pilot.

For anyone curious about more of the technical aspects behind the scenes then Jeff Wise writes about it frequently. http://jeffwise.net/

> Air France 440 was also shrouded in mystery (but nowhere near this degree), and turned out to be very poor airmanship by one pilot.

It was poor airmanship by two pilots (and other factors, including the feedback mechanisms and the lack of training for this particular high altitude scenario).

My understanding is that the pilot in the left chair didn't realize that the pilot in the right chair kept pulling his stick back. In boeing planes, the sticks move together, so that wouldn't be possible. And the pilot in the right chair clearly didn't understand that in the alternate law the fly by wire system was running in, his stick movements put the plane at risk.

Yes, it was a completely incorrect reaction by a single pilot, combined with a catastrophically bad design for the controls, which caused that crash. It is completely insane to me that anyone would think that averaging inputs from two pilots and providing no feedback would be even remotely a good idea.

The aircraft does provide feedback, it says, "DUAL INPUT, DUAL INPUT". IIRC this can be heard on the cockpit voice recorder of Air France 447.

I mean physical feedback. In any rationally designed aircraft, the controls are physically linked, such that moving one moves the other (or at the very least this arrangement is faked with servos). When two pilots attempt to give contradictory inputs, they immediately know it because they can feel the other one fighting.

Yes, in the Air France tragedy, the aural warning clearly wasn't enough. Through fear and panic, the pilots failed to understand what the plane was telling them. But the feeling of having a control yoke fight against you doesn't require much mental effort to process.

Aural warnings are so easy to ignore. There are a ton of stories that go like, "What is that annoying buzzing sound? Well, no time to worry about it now, I'm landing. <CRUNCH> Oh, it was the gear warning." Happened to a friend of mine, even.

I think it ultimately comes down to engaging with the primary sense you're already using. If you're doing something visual, then a visual warning (on whatever you're looking at) can be effective, while an aural warning won't. If you're listening to something then interrupting it with an audio warning will work great. Hand flying is a tactile experience, so that's the sense you want to work with.

I agree with you completely.

Also,

> Hand flying is a tactile experience, so that's the sense you want to work with.

is the primary reason why Boeing still uses yokes instead of sidesticks.

Aural warnings are so easy to ignore.

Yes. You give an example of someone ignoring a single aural warning. The case of AF447 was much worse.

There was a cacophony of different sounds and noises in the cockpit of AF447. All the various alarms are deliberately made to sound different. But when someone knows he's a minute from death, there's no way his reptilian brain can make sense of a plethora of simultaneous alarms. It will, instead, strive to tune them all out.

I remember a documentary where Duke Cunningham discussed his experiences as a fighter ace in Vietnam. In high stress situations he would switch his intercom to allow him to speak to his RIO, but not be able to hear his RIO. He didn't want the distraction. (Note: sadly, Cunningham disgraced himself in later life).

I built a gear warning system for my glider. The usual ones just have either as steady tone or a pulsing tone. I made mine do a pulsing tone with different speeds, then it actually spells out "WARNING GEAR UP" in morse code. I don't know morse code, but I figured the irregular pattern would make it more identifiable and harder to ignore.

I've seen it advised to turn off the aircraft radio when it's not useful and you're in the middle of something tricky, like climbing out from a low altitude, or landing in a field.

> I've seen it advised to turn off the aircraft radio when it's not useful and you're in the middle of something tricky, like climbing out from a low altitude, or landing in a field.

Makes sense. "Aviate, navigate, communicate".

That's correct (even though he did mention "watch the height" and could have followed up on that). If I remember correctly, even the left chair pilot also applied nose-up inputs at some point in time.

Well we could go into the whole 'swiss cheese' theory of accidents, and include a long list of causes. https://en.wikipedia.org/wiki/Swiss_cheese_model

Not an expert, but doesn't the flap already indicate that they crash landed? As otherwise plane would have sunk to the bottom ocean in one piece? I guess further analysis will say whether flap detached via chafe or on impact.

Also is there a chance they will be able to detect smoke debris on it (to confirm or deny chemical battery fire theory)?

> Air France 440 was also shrouded in mystery (but nowhere near this degree), and turned out to be very poor airmanship by one pilot.

It was flight 447. https://en.wikipedia.org/wiki/Air_France_Flight_447

IMO The mystery of MH370 is partially due to some incorrect assumptions, which can't be proven or disproven until the main wreckage is found, and/or the blackboxes recovered.

Where the wreckage ended up could depend several factors. eg. glide ratio of a 777 (~18:1), or how the 777 Fly-by-wire control system works under certain failure modes. There hasn't been a crew incapacitation crash in a fly-by-wire airliner before.

A small fire in the electrical bay could disable aircraft systems in unexpected ways, and possibly even burn out on its own, and the damage doesn't actually cause the jet to crash immediately. If the cockpit crew were incapacitated at cruise altitude, the jet could still end up 100 miles away from the point the engines flamed out.

Part of the mystery is due to the radical change in the flight path. It was supposed to fly North from Kuala Lumpur to Beijing.

But for some reason, the plane was turned around, and flew towards the Indian Ocean instead of China for at least an hour: https://upload.wikimedia.org/wikipedia/commons/f/f2/MH370_fl...

Merely incompetent crew or a technical failure would not cause that - it has to either be a hijacking or an unstable pilot doing it on purpose.

Turning around is a common procedure under mechanical events and mechanical explanations for what happened to MH370 are still one of the leading 2 theories.

Unless (puts on tinfoil hat) that piece of wreckage was placed there with the intent that it would be discovered. Nutty people will believe whatever they want.

And kept into an aquarium of oceanic water for a year...

A bit far fetched if you ask me.

It could have been placed there close to a year ago, but it just took this long to find it. :P

You just have to pay off the few people who report the results.

> It does mean that the Inmarsat positional analysis about the final location of the plane is likely correct.

Does it though? I'm not saying the analysis is incorrect, just wondering how predictable these ocean currents are. I understand that the debris surfacing at Reunion doesn't rule out the current search location, but that's different than confirming or proving it. I mean, can they just 'play back' the ocean currents and arrive at a specific spot? I wouldn't be surprised if there's so much uncertainty that all they can say with certainty is that it must have crashed somewhere in the Indian Ocean. Which isn't exactly new information.

The Inmarsat data seems pretty solid, but it's not very precise. There was always the possibility that the plane actually went down somewhere on the northern arc, rather than the southern arc as was assumed. The northern arc was never very likely because the plane would almost certainly have been noticed on that path, but this debris finding rules it out entirely.

(In case anyone is unfamiliar with just what the data showed, here's a quick summary image: http://ogleearth.com/wp-content/uploads/2014/03/MH370_Mar17....)

No, it was actually possible to exclude the northern arc based on the satellite data only:

http://www.airtrafficmanagement.net/2014/06/mh370-what-does-...

"the Doppler shift due to the satellite’s motion is not removed by the plane’s terminal when it pre-corrects the frequency of transmission, and thus there is an asymmetry between the BFO which would be produced by a plane flying north of the equator (and thus situated to the north of the satellite) compared to one flying south on a similar track."

Nice! Never heard that stuff. I stand corrected.

It's a perfect example for "science, it works." They managed to conclude quite a lot from a miniscule amount of data with the information that was never planned to be used for such purposes.

Sadly, people will attempt to overthink that. E.g. jeffwise.net was cited earlier as a forum discussing AF447. But read this from Jeff concerning the Inmarsat data:

   case 3. The plane did not go south at all.
   If this is the case, then the satellite
   communications system must have been compromised
   by hijackers who either flew the plane north to
   Kazakhstan or China (if only the BFO values were
   spoofed) or somewhere else within a huge circle
   encompassed by the 7th ping ring (if both BTO
   and BFO values were spoofed).

Yes, it's possible that occurred. But even Inmarsat itself didn't have a good understanding of this data. It's very very farfetched to think that some sinister elements, as part of a nefarious scheme, spoofed the data being sent to the satellite. IMO the probability is less than 1 in a million. So many other scenarios make more sense.

It appears to me not like overthinking, but like completely failing to understand the way the analysis I've quoted was done (if he wrote the details I've quoted were published). Nobody knew, before the analysis was done, that it would be even possible to use the Doppler effects of the communication recording.

This is what happens when you assume the conclusion first, then try to support it.

Normal inference: the plane may have gone north, satellite signals indicate it went south, therefore the plane didn't go north.

Crazy inference: the plane went north, satellite signals indicate it went south, therefore the signals were tampered with.

The Inmarsat position data was very controversial when it was first announced. This was because the flight path, the last radio contact and last radar signal were all recorded over the South China Sea; a completely different ocean to where the debris was found. Indeed, the first search operation was over and around the designated flightpath, which was literally oceans away from where the plane likely came down. Thanks to Inmarsat, we have a much better, though not completely accurate, understanding of what happened.

IIRC it　was controversial as it implies that the 777 was in controlled flight for several hours after it lost contact, making it a deliberate act rather than accident. Radar data released by the Malaysian military showed clearly that the plane turned west then south.

Note that the plane was tracked on military radar flying west from the South China Sea, across the Malay Peninsula, and over the Andaman Sea before it flew out of range. Despite this fact, the Malaysians allowed search and rescue efforts to remain focused on entirely the wrong ocean for two days before they finally told anybody that they might be looking in the wrong spot, and it was four days before they actually revealed that they had a full hour of additional radar data that showed the plane had definitely not ended up anywhere near its intended flight path.

Of course, even then the search was subsequently done in the Andaman Sea area under the assumption that the plane crashed near the position of its last radar contact, as the Inmarsat data wasn't announced until several days later.

All I'm saying is that this might support the Inmarsat conclusions, but that's not the same as proving it.

If my hypothesis is that all swans are white, finding a black swan would disprove it. Instead this is another white swan. It supports the hypothesis, but it doesn't prove it.

Note by the way that I have no reason to doubt the Inmarsat analysis. I think that was truly groundbreaking use of the data. All I'm saying is that this find doesn't really prove the analysis, nor help with narrowing down the search.

But did the plane crash on the ocean or it was shattered mid-air? Wouldn’t the debris be deformed if it had hit the water?

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