Flight MH370 Depressurization Scenarios

[Melbury's Brick]

Video report from Sky News....

Sky News speaks to a former pilot who says there is a scenario that could explain how the Malaysia Airlines flight disappeared

http://news.sky.com/story/1224061/flight-mh370-13-things-you-need-to-know



It was aired today. Unlike most on this site, I hate flying and spend the entire journey hanging on to the headrest of the seat in front of me with white knuckles! My only interest in aircraft is that they get me where I want to go in one piece, so I'm not qualified to comment about Sky's video. It's really just another chunk of speculation.

 

[Mick West]

Video report from Sky News....

Sky News speaks to a former pilot who says there is a scenario that could explain how the Malaysia Airlines flight disappeared

http://news.sky.com/story/1224061/flight-mh370-13-things-you-need-to-know



It was aired today. Unlike most on this site, I hate flying and spend the entire journey hanging on to the headrest of the seat in front of me with white knuckles! My only interest in aircraft is that they get me where I want to go in one piece, so I'm not qualified to comment about Sky's video. It's really just another chunk of speculation.

They suggest there was a cabin depressurization. The pilots attempted to set the autopilot heading for back to Kuala Lumpur, but then passed out. So the plane flew until it ran out of fuel, somewhere in the middle of the Indian Ocean. The passengers would be on their oxygen masks for 15 minutes, then would pass out. Everyone would be dead, and the plane would continue flying.

It seems pretty clear that the plane did not just blow up, or crash where contact was lost. This explanation is not impossible - but still just one of several possible explanations.

 

[Hama Neggs]

Wouldn't it take several minutes before the pilots passed out? They would have had to be preoccupied with more tasks than just dialing in a new heading.

 

[Mick West]

http://en.wikipedia.org/wiki/Time_of_useful_consciousness
At 35,000 feet it's 30 to 60 seconds.

Training is to immediately put on the masks though.

 

[Mark Barrington]

They suggest there was a cabin depressurization. The pilots attempted to set the autopilot heading for back to Kuala Lumpur, but then passed out. So the plane flew until it ran out of fuel, somewhere in the middle of the Indian Ocean. The passengers would be on their oxygen masks for 15 minutes, then would pass out. Everyone would be dead, and the plane would continue flying.

It seems pretty clear that the plane did not just blow up, or crash where contact was lost. This explanation is not impossible - but still just one of several possible explanations.

I don't know, wouldn't they first try to get to a low enough altitude to breathe before trying to set the autopilot? Is there some sort of scenario where the pilot's oxygen masks would not have been available?

 

[WeedWhacker]

Wouldn't it take several minutes before the pilots passed out? They would have had to be preoccupied with more tasks than just dialing in a new heading.

ALL pilots know that the immediate action in a decompression is to don the O2 masks. It's a "memory item" on the checklist. All pilots know of the brief time of useful consciousness at high altitude.

That Sky News video? The "former" airline pilot just wanted his 15 minutes of "fame", apparently.

 

[Mick West]

Here's an incident where they did not put on the masks, and the plane just kept flying:
http://en.wikipedia.org/wiki/1999_South_Dakota_Learjet_crash
http://www.ntsb.gov/doclib/reports/2000/AAB0001.pdf

Following the depressurization, the pilots did not receive supplemental oxygen in sufficient time and/or adequate concentration to avoid hypoxia and incapacitation. The wreckage indicated that the oxygen bottle pressure regulator/shutoff valve was open on the accident flight. Further, although one flight crew mask hose connector was found in the wreckage disconnected from its valve receptacle (the other connector was not recovered), damage to the recovered connector and both receptacles was consistent with both flight crew masks having been connected to the airplane's oxygen supply lines at the time of impact. In addition, both flight crew mask microphones were found plugged into their respective crew microphone jacks. Therefore, assuming the oxygen bottle contained an adequate supply of oxygen, supplemental oxygen should have been available to both pilots' oxygen masks.

[A] possible explanation for the failure of the pilots to receive emergency oxygen is that their ability to think and act decisively was impaired because of hypoxia before they could don their oxygen masks. No definitive evidence exists that indicates the rate at which the accident flight lost its cabin pressure; therefore, the Safety Board evaluated conditions of both rapid and gradual depressurization.

If there had been a breach in the fuselage (even a small one that could not be visually detected by the in-flight observers) or a seal failure, the cabin could have depressurized gradually, rapidly, or even explosively. Research has shown that a period of as little as 8 seconds without supplemental oxygen following rapid depressurization to about 30,000 feet (9,100 m) may cause a drop in oxygen saturation that can significantly impair cognitive functioning and increase the amount of time required to complete complex tasks.

A more gradual decompression could have resulted from other possible causes, such as a smaller leak in the pressure vessel or a closed flow control valve. Safety Board testing determined that a closed flow control valve would cause complete depressurization to the airplane's flight altitude over a period of several minutes. However, without supplemental oxygen, substantial adverse effects on cognitive and motor skills would have been expected soon after the first clear indication of decompression (the cabin altitude warning), when the cabin altitude reached 10,000 feet (3,000 m) (which could have occurred in about 30 seconds).

Investigations of other accidents in which flight crews attempted to diagnose a pressurization problem or initiate emergency pressurization instead of immediately donning oxygen masks following a cabin altitude alert have revealed that, even with a relatively gradual rate of depressurization, pilots have rapidly lost cognitive or motor abilities to effectively troubleshoot the problem or don their masks shortly thereafter. In this accident, the flight crew's failure to obtain supplemental oxygen in time to avoid incapacitation could be explained by a delay in donning oxygen masks of only a few seconds in the case of an explosive or rapid decompression or a slightly longer delay in the case of a gradual decompression.

In summary, the Safety Board was unable to determine why the flight crew could not, or did not, receive supplemental oxygen in sufficient time and/or adequate concentration to avoid hypoxia and incapacitation.

 

[WeedWhacker]

Is there some sort of scenario where the pilot's oxygen masks would not have been available?

No, highly unlikely. Again, the first action is donning masks...they are a "quick don" design, can be swiftly grasped and placed on the head with one hand.





For a rapid decompression at high altitude, the masks are first, it is

"Oxygen masks ON, 100%"
"Communications, establish"

(That's verifying 100% O2 setting, and communication on the Interphone, and over the speakers, for the pilots to talk and hear each other).

An emergency descent must be initiated next, first the determination of whether or not there is structural damage. If damage is suspected, then the current airspeed is maintained, and not exceeded during the descent (this presumes that any increase in airspeed might be dangerous). If no structural damage is suspected, then the airspeed is allowed to increase to Mmo/Vmo, in order to achieved maximum rate.

This must be done with alacrity, since as mentioned, the Pax O2 only lasts about 15 minutes.

 

[Mark Barrington]

ALL pilots know that the immediate action in a decompression is to don the O2 masks. It's a "memory item" on the checklist. All pilots know of the brief time of useful consciousness at high altitude.

That Sky News video? The "former" airline pilot just wanted his 15 minutes of "fame", apparently.

The Sky News video mentioned a scenario where the oxygen system for the pilots malfunctioned on a Helios airline flight in 2005. That's barely plausible. Still, it seems more likely they would be concentrating on losing altitude than setting the course back towards the point of origin.

I think this theory is unlikely, but if it were true, the new search area would be so far from anything that it might be just about impossible to find the plane. Doesn't the U.S. have an airbase in the middle of the Indian Ocean?

Edit: Diego Garcia: http://en.wikipedia.org/wiki/Diego_Garcia (and it's British, not U.S.)

 

[Mick West]

And another with a 737, thought to be a gradual decompression due to flight crew errors with the pressurization system. Again the plane continue to fly
http://en.wikipedia.org/wiki/Helios_Airways_Flight_522

When the aircraft arrived from London Heathrow earlier that morning, the previous flight crew had reported a frozen door seal and abnormal noises coming from the right aft service door, and requested a full inspection of the door.[2][6] The inspection was carried out by a ground engineer who then performed a pressurization leak check. In order to carry out this check without requiring the aircraft's engines, the pressurisation system was set to "manual". However, the engineer failed to reset it to "auto" on completion of the test.[7]

After the aircraft was returned into service, the flight crew overlooked the pressurisation system state on three separate occasions: during the pre-flight procedure, the after-start check, and the after take-off check. During these checks, no one in the flight crew noticed the incorrect setting.[8] The aircraft took off at 9:07[3] with the pressurisation system still set to "manual", and the aft outflow valve partially open.[9]

As the aircraft climbed, the pressure inside the cabin gradually decreased. As it passed through an altitude of 12,040 feet (3,670 m), the cabin altitude warning horn sounded.[3] The warning should have prompted the crew to stop climbing,[10] but it was misidentified by the crew as a take-off configuration warning, which signals that the aircraft is not ready for take-off, and can only sound on the ground.[10]

In the next few minutes, several warning lights on the overhead panel in the cockpit illuminated. One or both of the equipment cooling warning lights came on to indicate low airflow through the cooling fans (a result of the decreased air density), accompanied by the master caution light. The passenger oxygen light illuminated when, at an altitude of approximately 18,000 feet (5,500 m), the oxygen masks in the passenger cabin automatically deployed.[11][12]

Shortly after the cabin altitude warning sounded, the captain radioed the Helios operations centre and reported "the take-off configuration warning on" and "cooling equipment normal and alternate off line".[3] He then spoke to the ground engineer and repeatedly stated that the "cooling ventilation fan lights were off".[3] The engineer (the one who had conducted the pressurization leak check) asked "Can you confirm that the pressurization panel is set to AUTO?" The captain, however, disregarded the question and instead asked in reply, "Where are my equipment cooling circuit breakers?".[12] This was the last communication with the aircraft.[13]

It seems very unlikely. But clearly something very unlikely happened. I just hope we find out what.

 

[Hama Neggs]

http://en.wikipedia.org/wiki/Time_of_useful_consciousness
At 35,000 feet it's 30 to 60 seconds.

Training is to immediately put on the masks though.

That's quick! On the other hand, as you say, the FIRST priority is oxygen masks, and they know it.

 

[WeedWhacker]

The Sky News video mentioned a scenario where the oxygen system for the pilots malfunctioned on a Helios airline flight in 2005.

Actually, the major malfunction on that Helios flight was Human...both pilots mis-identified a cabin pressurization problem, and never even donned their masks!

http://en.wikipedia.org/wiki/Helios_Airways_Flight_522

Shortly after the cabin altitude warning sounded, the captain radioed the Helios operations centre and reported "the take-off configuration warning on" and "cooling equipment normal and alternate off line". He then spoke to the ground engineer and repeatedly stated that the "cooling ventilation fan lights were off". The engineer (the one who had conducted the pressurization leak check) asked "Can you confirm that the pressurization panel is set to AUTO?" The captain, however, disregarded the question and instead asked in reply, "Where are my equipment cooling circuit breakers?". This was the last communication with the aircraft.

That was a 'comedy" of errors...except it turned out tragically. They heard the cabin altitude warning, and thought it was the takeoff Config.

 

[Mark Barrington]

Actually, the major malfunction on that Helios flight was Human...both pilots mis-identified a cabin pressurization problem, and never even donned their masks!

http://en.wikipedia.org/wiki/Helios_Airways_Flight_522

Shortly after the cabin altitude warning sounded, the captain radioed the Helios operations centre and reported "the take-off configuration warning on" and "cooling equipment normal and alternate off line". He then spoke to the ground engineer and repeatedly stated that the "cooling ventilation fan lights were off". The engineer (the one who had conducted the pressurization leak check) asked "Can you confirm that the pressurization panel is set to AUTO?" The captain, however, disregarded the question and instead asked in reply, "Where are my equipment cooling circuit breakers?". This was the last communication with the aircraft.

That was a 'comedy" of errors...except it turned out tragically. They heard the cabin altitude warning, and thought it was the takeoff Config.

You're right, of course. I was confused by how the incident was described in the video, which seemed to indicate an equipment malfunction, not human error.

 

[Mick West]

Actually, the major malfunction on that Helios flight was Human...both pilots mis-identified a cabin pressurization problem, and never even donned their masks!

http://en.wikipedia.org/wiki/Helios_Airways_Flight_522

Shortly after the cabin altitude warning sounded, the captain radioed the Helios operations centre and reported "the take-off configuration warning on" and "cooling equipment normal and alternate off line". He then spoke to the ground engineer and repeatedly stated that the "cooling ventilation fan lights were off". The engineer (the one who had conducted the pressurization leak check) asked "Can you confirm that the pressurization panel is set to AUTO?" The captain, however, disregarded the question and instead asked in reply, "Where are my equipment cooling circuit breakers?". This was the last communication with the aircraft.

That was a 'comedy" of errors...except it turned out tragically. They heard the cabin altitude warning, and thought it was the takeoff Config.

The analysis here a fascinating read. Page 112 (pdf 124) on:
http://www.aaiasb.gr/imagies/stories/documents/11_2006_EN.pdf

Apparently they did not put on their masks, as they did not realize they were needed.

 

[Melbury's Brick]

The analysis here a fascinating read. Page 112 (pdf 124) on:
http://www.aaiasb.gr/imagies/stories/documents/11_2006_EN.pdf

Apparently they did not put on their masks, as they did not realize they were needed.

Which supports the point that people in any occupation can do the wrong, and sometimes inexplicable thing no matter how thorough their training. The idea someone "wouldn't have done this" or "wouldn't have done that" because they are trained pilots, or policemen, or emergency service personnel etc. is a cry we often hear from conspiracy theorists.

(Thanks Mick, for embedding the "Sky news" video. I couldn't make it happen for some reason.)

 

[TWCobra]

The crew of MH370 reached FL350 and was beginning stable cruise. They replied to an instruction from KL ATC to switch to Ho Chi Minh ATC. That was the last transmission.

The Helios crew were climbing with numerous warnings going off, that they failed to interpret correctly. The 737 climbs fairly rapidly and the cabin never pressurised.

If the 777 had a pressurisation problem, a large red "Cabin Altitude" message would have appeared on the EICAS screen followed by the same alarm you get when an engine catches fire. As Weedwhacker says, the first action is to don the oxygen mask and make sure 100% oxy is selected.

Once that is done, the life and death emergency is pretty much finished and becomes more a matter of an expeditious descent.

There was no indication of a depressurisation when the crew responded to the frequency change. It only takes one of the pilots to respond correctly if it happens. It also would have triggered ACARS messages.

This scenario is unlikely.

 

[Melbury's Brick]

More speculation that the plane continued to fly after last contact....

http://www.nytimes.com/2014/03/14/world/asia/missing-malaysia-airlines-flight-370.html?_r=0

SEPANG, Malaysia — The focus of the search for a missing Malaysia Airlines jetliner shifted westward on Thursday, toward the vastness of the Indian Ocean, as Malaysian authorities denied a variety of reports related to the jet's disappearance and experts pored over military radar data that seemed to indicate that the flight had turned west and remained airborne long after its last contact with ground controllers.
Yet in a measure of the continued caution and bafflement among the authorities here, Malaysia's defense minister, Hishammuddin Hussein, said the main search effort continued to be east of the Malaysian peninsula, in the Gulf of Thailand and the South China Sea.

Even so, American naval aircraft were redeployed to the Strait of Malacca, west of Malaysia, one of several indications that the search for Malaysia Airlines Flight 370 was turning away from the eastern waters that have been combed by dozens of ships and airplanes for days, and toward the Andaman Sea and the wider Indian Ocean.

In a news briefing that was more structured and organized than those of earlier days, the Malaysian authorities denied a widely circulated report that the jetliner, a Boeing 777, had transmitted technical data after contact with the cockpit was lost around 1:30 a.m. Saturday morning, when the airplane was on course toward Beijing, its scheduled destination.
The report, by The Wall Street Journal, asserted that Rolls-Royce, the maker of the aircraft's engines, had received routine data transmissions from those engines on schedule after contact with the cockpit was lost, suggesting that the plane remained aloft for several more hours.
But the chief executive of Malaysia Airlines, Ahmad Jauhari Yahya, said that the last technical data received from Flight 370 came at 1:07 a.m. Saturday, when the aircraft was still in touch with ground controllers, and that it indicated no trouble with the plane.
"That was the last transmission," Mr. Ahmad Jauhari said at a news conference in Sepang, the location of the international airport serving Kuala Lumpur. "It did not run beyond that."
Malaysian authorities said that both Rolls-Royce and Boeing had told them they did not receive any further data from the airplane after the transmission at 1:07 a.m.
The authorities said separately that nothing had come of images recorded by Chinese satellites on Sunday and posted online on Wednesday, which appeared to show large objects floating in the South China Sea. Vessels dispatched to the area found nothing, they said, and Mr. Hishammuddin said he was told by Chinese officials that "the images were released by mistake and did not show any debris."

 

[ralph Leo]

With nothing being found and reports of the plane flying for 4 hrs after last contact is there any chance it was hijacked and flown somewhere and landed?

 

[WeedWhacker]

If the 777 had a pressurisation problem, a large red "Cabin Altitude" message would have appeared on the EICAS screen followed by the same alarm you get when an engine catches fire.

Exactly. For those unfamiliar, 'EICAS' is an acronym for "Engine Indication and Crew Alerting System". I have found an instructional video on YouTube (that appears to be part of some airline's CBT program...as designed by Boeing, no doubt). This is specific to the B767, but is very similar to a B777 in most respects:



EDIT: My use of the acronym "CBT" refers to 'Computer Based Training'...a method that is becoming more commonplace, at many airlines. In fact, for one of my Type Ratings, the actual "Oral" was in fact, conducted on the computer! "Times, they are a'changin!"

(Sorry for the interruption....MicroSoft decided to suddenly "take over" and add "Security updates" to my OS, right as I was typing).

 

[Pete Tar]

With nothing being found and reports of the plane flying for 4 hrs after last contact is there any chance it was hijacked and flown somewhere and landed?

The report of flying for four hours is someone's reported speculation, it's officially denied. It's unfortunately going to persist and confuse things.
(there is a very remote chance it was secretly diverted and landed, but airfields that can host a 777 tend to be visible from space, so it's really unlikely.)

When does the engine data transmission usually happen - is it part of the transponder signal or separate?
Is there a way for it to have sent data after all other contact was off?

 

[Joe]

The report of flying for four hours is someone's reported speculation, it's officially denied. It's unfortunately going to persist and confuse things.
(there is a very remote chance it was secretly diverted and landed, but airfields that can host a 777 tend to be visible from space, so it's really unlikely.)

When does the engine data transmission usually happen - is it part of the transponder signal or separate?
Is there a way for it to have sent data after all other contact was off?

According to Rolls-Royce's website, their aircraft engine data is transmitted via satellite feed. Rolls- Royce would analyze the data submitted and make recommendations to the airline for engine maintenance, as appropriate.

 

[TWCobra]

I have to say this now as it appears to be the most likely scenario. Barring further revelations I believe that this aircraft has had it's flight path interfered with by one of the pilots.

The lack of any wreckage coupled with the transponder being apparently turned off is the clue here.

There are no indications of terrorism or inflight breakup. A crew incapacitation would have resulted in a Helios type event and triggered numerous ACARS messages as the flight progressed. The aircraft would have been tracked as there is no reason that the transponder would have been switched off.

The US is moving towards the same conclusion IMHO.

http://www.washingtonpost.com/world...688034-aa68-11e3-b61e-8051b8b52d06_story.html

You are already seeing reports of pilots families being interviewed. This would be a routine investigatory function anyway but I predict we will start seeing more stories on this angle very shortly.

I hope I am wrong. Pilots occupy a position of trust in the community. But I have been saying this privately since day three of the event, where it was becoming apparent there was no wreckage to be found anywhere where it should be, and the news of the primary radar traces of an aircraft heading west.

I really do hope to be proved wrong.

 

[Pete Tar]

Is there a difference between 'turned off' and 'stopped transmitting due to technical failure' so that it can be 100% determined it was turned off?

 

[Pete Tar]

According to Rolls-Royce's website, their aircraft engine data is transmitted via satellite feed. Rolls- Royce would analyze the data submitted and make recommendations to the airline for engine maintenance, as appropriate.

Yes but that might not apply definitely to this flight. I hope they clear this up via a statement.

ETA from ATS

According to Malaysia Officials, it is Rolls Royce who told them via their investigation that after contact with the plane was lost there were no more data transmissions. And they did stand there with people from RR there and state this.

 

[Mick West]

Is there a difference between 'turned off' and 'stopped transmitting due to technical failure' so that it can be 100% determined it was turned off?

I don't think so. When you turn a transponder to standby, or off, it just stops transmitting (as that's what the intent is).

 

[Joe]

Yes but that might not apply definitely to this flight. I hope they clear this up via a statement.

ETA from ATS

According to Malaysia Officials, it is Rolls Royce who told them via their investigation that after contact with the plane was lost there were no more data transmissions. And they did stand there with people from RR there and state this.

Yes but what TWcobra said makes the most sense . I heard the pilot had a flight simulator at his home ? Seems strange being he had so many flight hours ? http://www.hindustantimes.com/world...ry-plane-under-scrutiny/article1-1194558.aspx

 

[Pete Tar]

Not really, could easily be a hobby passion.
But they're definitely widening their possible scenarios.

 

[TWCobra]

I have Flight Simulator X set up on my desktop at home with a high end joystick.
I use it at the moment to make historical aviation recreations (you can see one on my YouTube channel) and it is also good for flight simulator check revision.
It is not unusual for pilots to do this.
I believe the MAS captain may have done a full simulated 777 cockpit. I don't think much should be read into that in relation to this incident.

 

[Pete Tar]

The Wall Street Journal has issued a correction to its report early Thursday that MH370 flew for hours after losing contact with ground control based on signals from systems in the plane's Roll-Royce engines. The theory that the plane flew for hours is based on a signal coming from a different system inside the plane – a satellite-communication link – and not the Rolls-Royce engines, the Journal now reports.

Here's the correction: Corrections & Amplifications U.S. investigators suspect Malaysia Airlines Flight 370 flew for hours past the time it reached its last confirmed location, based on an analysis of signals sent through the plane's satellite-communication link designed to automatically transmit the status of some onboard systems, according to people familiar with the matter. An earlier version of this article incorrectly said investigators based their suspicions on signals from monitoring systems embedded in the plane's Rolls-Royce PLC engines and described that process.


www.theguardian.com...

 

[ralph Leo]

But still reports seem to indicate that the flight didn't just crash when it first fell off the radar:
http://gma.yahoo.com/malaysia-airli...cean-194746310--abc-news-topstories.html?vp=1
You would think it would be hard to hijack and hide a jetliner with all the onboard electronics, radar and satellites in use today.

 

[WeedWhacker]

You would think it would be hard to hijack and hide a jetliner with all the onboard electronics, radar and satellites in use today.

"IF" (and only being speculative here)...."IF" one's objective was to "hide" an airliner, and one knew the systems well enough...yes, turning off (or to 'STBY' in the case of transponders) is easily accomplished. Circuit Breakers could be pulled (opened), rendering any component then unpowered.

There is a LOT of room for 'speculation', however.....

 

[Melbury's Brick]

Hijack seems to be back on the table, according to "sources"......

http://uk.reuters.com/article/2014/03/14/uk-malaysiaairlines-flight-idUKBREA2701C20140314

(Reuters) - An investigation into the disappearance of a Malaysia Airlines jetliner is focusing more on a suspicion the flight was deliberately diverted, as evidence suggests it was last headed out over the Andaman Islands, sources familiar with the Malaysian probe said.
In a far more detailed description of military radar plotting than has been publicly revealed, two sources told Reuters that an unidentified aircraft that investigators suspect was missing Flight MH370 appeared to be following a commonly used navigational route when it was last spotted early on Saturday, northwest of Malaysia.
That course - headed into the Andaman Sea and towards the Bay of Bengal - could only have been set deliberately, either by flying the Boeing 777-200ER jet manually or by programming the auto-pilot.
A third investigative source said inquiries were focusing more on the theory that someone who knew how to fly a plane deliberately diverted the flight, with 239 people on board, hundreds of miles off its course from Kuala Lumpur to Beijing.
"What we can say is we are looking at sabotage, with hijack still on the cards," said the source, a senior Malaysian police official

However (same report).......

Despite the increased focus on the Indian Ocean, a senior Malaysia Airlines official expressed pessimism over the chances of finding the aircraft there.
"We are actually searching that part of the geography, but the likelihood of the aircraft being there is probably very, very low," Hugh Dunleavy, the airline's chief of operations, told Reuters in Beijing on Friday.

Malaysian officials have already received some criticism for the way they have handled this so far. I guess there'll be more to come.

 

[Balance]

Angus Walker @anguswalkersaxo
MH370 coverage goes like this
1) Europe/ US evenings - latest rumours/breaking lines
2) Asian pm - those rumours denied
3) repeat daily

 

[Pete Tar]

Yeah it's not really Malaysia's fault that it has to clear up confusion and deny rumours run with by the press.

 

[Melbury's Brick]

Yeah it's not really Malaysia's fault that it has to clear up confusion and deny rumours run with by the press.

They now seem to be agreeing with the rumours that the flight continued long after the last contact.


Here's a rumour....Did Malaysian Airways deny the "flew on" theory because it may implicate one of their pilots and open the possibility that the airline could be criminally responsible? Would that action have perpetuated a search in the wrong place? That would clear the decks for an even uglier thought.....Would it be (in that scenario) in Malaysian Airlines interests that the plane never be found?
(I'm sounding a bit ct here.)

Either way, this is off topic re. depressurization and probably should be in the main "Speculation" thread.

 

[Paul29]

The discussions above imply that loss of pressure was accidental. I believe that it was intentional.
The pilot hijacked the aircraft and shutoff the transponder and communications.
He took it up to 45,000 feet (beyond max ceiling), put on his oxygen mask, dumped cabin pressure (people unprepared would have seconds to respond), and then flew the aircraft somewhere.

I lost a canopy at 50,000 with my mask hooked to the helmet but off my face. Seconds not minutes ...

 

[WeedWhacker]

He took it up to 45,000 feet (beyond max ceiling)...

The scenario of running the cabin altitude up to disable everyone in the cabin is possible, but it would not require the additional step of climbing the jet above its Service Ceiling. The same effect would be accomplished just as effectively at FL 350.

So, the reports of the climb to FL 450 seem doubtful...at least at this stage.

 

[Pete Tar]

There is some question that taking it to that height is logistically impossible and highly likely to induce a stall. We have to not assume that figure is necessarily accurate.
The same effect could have been achieved at a lower height.
"lost a canopy" what does that mean? In a 777?

 

[TWCobra]

There are other possible scenarios there. The 777 has oxygen generators for the passengers which last for 12 minutes. After that time, depressurising the cabin at normal cruising altitude is enough to incapacitate the passengers.

The cabin crew have oxygen bottles which they can use. Whether or not they would be very effective at 35000 feet, think of every film you have seen of climbers on Everest, is problematic.

The problem is that the higher you go, unless the oxygen is delivered under substantial pressure, it is not doing you any good.

 

[WeedWhacker]

"lost a canopy" what does that mean? In a 777?

I will presume to answer, in case the member doesn't notice first: No, the poster's experience indicates it was in a military fighter.