MH370 – what happened | Hacker News Reader

MH370 – what happened

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33 pointssabon33 comments

This theory is not plausible as Malaysian authorities announced that primary radar returns suggest the plane turned SSW.[1] Additionally the airspace at the Chinese coast is most likely closely monitored 24/7.

Another good source for information/speculation is the Airliners Thread, currently at part 12: http://www.airliners.net/aviation-forums/general_aviation/re...

[1] http://www.frequentbusinesstraveler.com/2014/03/search-for-m...

If they managed to turn around partially before they understood what was going on, autopilot could have continued in that direction as well. That could possibly be why they're looking at the Malacca straights now instead of the original search zone since primary radar supposedly detected the plane in that vicinity at 2:40am, an hour after it went dark.

Seems like they would have donned O2 masks, lowered altitude, and made for an emergency landing.

Interesting development on this flight. The co-pilot has a history of welcoming people into the cockpit:

http://www.news.com.au/travel/travel-updates/mh370-mystery-i...

Even if there was a slow decompression to 13,500 ft cabin altitude, almost no one would be unconscious. Hypoxia begins to set in as early as 5000 ft, but oxygen isn't even required in aircraft until you spend more than 30 minutes about 12,500 ft. Above 15,000 ft the average time of useful consciousness is still 30+ minutes.

Pilots are trained to 'detect' hypoxia but it is still /incredibly/ difficult.

>Even if there was a slow decompression to 13,500 ft cabin altitude, almost no one would be unconscious.

This person's theory claims that the autopilot would /maintain/ the aircraft's altitude. The cabin may slowly depressurise, but the altitude remains the same. TUC at 35,000 feet - normal cruise altitude - is only 30 to 60 seconds (on average!), which is nowhere near the 30 minute mark that it would be at <15,000 feet.

I am not experienced enough to comment on the plausibility of other aspects of this person's theory, but in terms of unconsciousness caused by decompression, it definitely seems plausible.

Though this article is likely dead I'll respond anyways. As the author notes, when cabin altitude reaches 13,500 ft, oxygen masks automatically deploy. This pretty much destroys the entire theory.

I agree about detecting hypoxia, it is very hard.

Considering China sent ships into the suspected area others are in I tend to discount the idea they would have RADAR logs of it flying beyond that point. They have no reason to lie about this one unless we have an incident similar to the Russian shoot down of KAL 007

Some pilots report debris @ N9.72 E107.42 https://www.google.com/maps/place/9°43'12.0"N+107°25'12.0"E)

Edit: satellite images are provided for a search: http://www.tomnod.com/nod/challenge/malaysiaairsar2014

This suggestion mentions "300nm" and "50nm" distances. To my eye these are 'nanometres', so is this a typo or am I missing something?

Nautical miles

It's a nautical mile (about 1.8 km). A standard unit of distance in aviation.

Generally nautical miles should be represented as NM, with nanometre as nm.

A few thoughts:

Anyone here who is stating categorically 'this' or 'that' cannot/must happen is uWotm8ing you. There is no compendium of mistakes. The systems layers of a modern jumbo jet are so fantastically complex there will be unknown bugs for a long time. The things cannot be flown or landed very well with out a computer http://www.youtube.com/watch?v=6HuGYrbSSP4

The concept of flight is still enigmatic. Like Zicam, it is known only that it works most times. How things fly is still a bit of a mystery.

If we are going to use '70s era analog blackboxes, where are going to keep having these '70s era horror stories. I am completely miffed as to how NSA can gather so much data from a relatively cheap and simple device, but blackbox tech is still where it is at.

If you have the time,look into the US Military's crash record [if you can find data...]. on the face of it, it would appear the war branches of american diplomacy are slamming expensive gear into the ground almost daily. Are their pilots shitty? Are the aircraft obsolete? No and yes, but the second one is super interesting because even in the face of massive obsolescence the wreck rate is relatively low. Also, the more shit you have up in the air, the more likely it becomes that something will hit the ground. No matter the skill of your Operators, if you fly birds constantly you will have constant issues.

If there was one thing that would change this particular situation, it would be telemetry, but the facts of the matter are that there are places on our planet that are unreachable, there are bugs and errors of which we are unaware that we are unaware, and if you use outdated tech you give outdated info.

https://news.ycombinator.com/item?id=7377690

If oxygen masks don't deploy when cabin pressure falls enough to make the passengers unconscious, then what is their purpose? It's hard to believe they could have such a massive design fault. Is there no sensor that could detect the depressurization?

No, the guy is just misinformed. You won't become unconscious at 12500ft. In fact it's perfectly legal to fly at 12000ft for 30 mins. Pikes Peak is 14115ft and I don't think people are all becoming unconscious up there. Also there will always be a very obvious alarm sounding when there is a depressurization. In the Helios flight they just thought the warning was something else (i.e. pilot error / incompetence).

I'm not sure about the sensitivity of pressure sensors so I can't comment on that, but in most cases where oxygen masks are required, it is rapid decompression caused by the pressurisation system failing or a physically broken part of the aircraft that has exposed the cabin to the outside atmosphere. I'm not aware of a case like this (if this person's theory is at all plausible) where depressurisation happens slowly.

Summary: It’s plausible that a fuselage section near the SATCOM antenna adapter failed, disabling satellite based - GPS, ACARS, and ADS-B/C - communications, and leading to a slow decompression that left all occupants unconscious. If such decompression left the aircraft intact, then the autopilot would have flown the planned route or otherwise maintained its heading/altitude until fuel exhaustion.

May be I am wrong, but If the gps failed, how can the autopilot work?

Autpilots existed long before GPS. Most of an aircraft's sensors would be considered primitive by the standards of this site, including measuring airspeed by literally sticking a straw out of the nose.

I'm not too familiar with modern autopilots, but afaik the systems are not the magic machines people think they are. All they do is hold course and speed by monitoring sensors such as the pitot tube, air density gauge, gyroscope, and compass.

When the summary says "planned route", they probably mean inputted heading and altitude. The aircraft would carry enough fuel to complete the route from start to finish, so we can infer that he means it will fly in a straight line until it ran out of fuel, not that it would land at the destination airport itself.

Most planes don't use GPS directly, but rather combine (with something like a kalman filter perhaps) it with at least the inertial navigation system to get position fixes. That way if the GPS fails, you have more or less graceful degradation of position fixes.

An aircraft flying unresponsive and undetetected into the most militarised areas on the planet (China, North Korea, Vietnam etc) does not sound plausible.

Would all the occupants of the aircraft suffer at the same time? I think not, someone would notice and raise an alarm.

Hypoxia isn't friendly like that. You don't feel like you're losing oxygen, you will just fall unconscious.

All 240? There would be some distribution.

It seems crazy that 15 years after Payne Stewart's plane went down for this exact reason, there are no cabin sensors (measuring partial-pressure of the oxygen?) to alert the crew that there is a small leak. Am I missing something?

When an aircraft decompresses, the total pressure drops, so pressure sensors are just as useful as oxygen partial pressure sensors. There are pressure sensors in the cabin -- they are used to control the pressurization system, sound low pressure alarms and deploy passenger air masks.

I guess spy satellites aren't as good as Hollywood has made out...

I would have imagined it wouldn't be that hard to point some satellites at the search area and look for something on the surface of the water, or a new impact area on land.

I'm sure Hollywood's depictions of spy satellites are just as accurate as its depictions of hacking.

Most planes do not crash because of terrorism/hijacking. It is unlikely this one did either. Annoying to see media some stories harping on the possibility it was hijacked when there is zero evidence.

Again, this is nothing more than wild speculation. We should just wait until we find it and analyse the material on the black box.

Does he seriously assume that the cabin pressure is not monitored?

This guy was onto something. The plane was last seen by military at Mallaca Strait, opposite direction of search area.

Malaysian Military official tells Reuters plane flew for more than an hour after vanishing from air traffic control screens

http://www.reuters.com/article/2014/03/11/malaysia-airlines-...

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