And that's exactly the point made by the person who brought it up. To be a little clearer, the access hatch is outside the door, but within the forward galley, under a carpet, and requires a special tool to loosen the screws. It's not exactly easily accessible to the passengers but it is outside the cockpit.

Ring - can u dumb that down a bit and explain the popping of the cabin valves to a layman?

For those of you who don't know what this means, the "EE" (electrical) racks are under the passenger compartment floor, just behind the nose wheel well in front, and just in front of the aft pressure bulkhead in back. Neither is meant to be normally accessible in flight. There is a hatch in the cockpit floor through which we gain access to the forward EE rack at times, but we normally get to it through the forward cargo bay, which we access through the forward cargo door - below the passenger deck. Kind of a PIA in flight. The aft EE rack is not accessible during flight at all - it sits behind the center bulkheads that effectively divide the lower cargo deck into front and rear halves.

So, in other words, if someone accessed even the forward EE rack in flight, they knew how to do it and expended some effort in getting to it. Take that for what it's worth.

The 'altitude' inside the cabin is controlled by a system that controls the flow of air OUT of the cabin. In a perfect world, the cabin of an airplane would be an airtight chamber. It's actually pretty leaky, but nonetheless it works most of the time.

On a flight, say, taking off from a sea level airport and landing at a sea level airport, the plane, if the trip is long enough, will climb to it most efficient altitude, say, on a x-country flight, 38000 feet. Obviously, we humans cannot survive the lack of oxygen (or the temp) at that altitude, so the plane is 'pressurized', pumped full of air that has been heated, or sometimes cooled to some shirtsleeve temp and altitude. The system is setup ahead of time, programmed for the flight. Normally, fuselages these days are designed for a working pressure of 8 to 15 PSI. Limits can and are higher, but these numbers are average. What that means is that the DIFFERENCE in inside and outside pressure is 8 to 15 PSI. That usually translates to a cabin ALTITUDE of 8000-ish feet above sea level. The fuselage is stressed to always have some positive pressure in it, negative pressure is bad.

The system does this by taking compressed air from the engines (simple explanation here) and pumping it into the cabin. The pressure (altitude) in the cabin is regulated by the system opening and closing, regulating, actually the leakage (outflow) of air from the (mostly) airtight cabin. A lot of other things are going on as well, but the simple answer is that the flow of air out of the cabin is what is controlled.

What is ASSuMEd is the the flow of air into the cabin is relatively constant, AND more importantly, greater volume than is being let out by the cabin controller. There are times that things can be in flux, and you feel a 'bump' in your ears.

Worst case normal-normal scenario, high differential pressure (high plane altitude), top of descent, throttles are brought to idle, or lower power, reducing the air coming in, and the outflow valves, even closed, cannot maintain the cabin pressure.

Back to MH370. Cruise altitude set for 10700 meters (you fly metric altitudes over there), or approx. 35000 feet. Cabin controller sets cabin altitude based on that, and allows cabin to go maximum differential pressure, lowest cabin altitude for pax comfort. Someone orders the plane to climb, in this case above max ceiling, and the best the cabin controller can do is to maintain this max differential as the plane climbs, The cabin alt climbs, uncomfortably fast, because the max dif pressure is absolute. the altitude alerter in this cockpit cannot be set above maximum, so the climb above service ceiling has to be done on a vertical rate, or hand flown. At the weight they were at one hour into this flight, the performance ceiling was probably 38000 or so. Hand flying was probably a workout. My bet is that the airplane, if it really made it to 45000, stalled, and fell off on a wing, diving, and a good guess is that the next altitude of 23000 feet was a recovery from the stall. Could that episode have been done on autopilot? Maybe, but still incredibly lucky to have escaped tearing something off of the airplane.

At the top of this climb, once started down, the speed grows scary VERY quickly, and the engines were probably idled. No air coming in, the cabin altitude climbed VERY quickly. My bet is that the outflow valve was intentionally manually opened prior or during this climb, after the pilot/s were on 100% oxygen, and pressure breathing. Anyone never having experienced this, it is something you had better have mastered prior to having to do it for real. The mask pressure flows oxygen, Aviators' Breathing Oxygen, into the mask, and this pressure inflates your lungs. you have to exhale hard to get it to stop. Most people puke when you have to actually do it unprepared.

Again, the pax had to be 'neutralized' prior to getting back in cell range. Sounds brutal, sorry, but the bad guys learned from 9-11 too.

Investigators searching for Malaysia Airlines Flight 370 conclude plane was hijacked: Malaysian official - NY Daily News

Updated: Saturday, March 15, 2014, 12:19 AM

Investigators searching for Malaysia Airlines Flight 370 conclude plane was hijacked: Malaysian official
A Malaysian government official said that hijacking was no longer just a theory: 'It is conclusive.' No motive has yet been established, the official said, and it is not yet clear where the plane was taken. Malaysian officials have said military radar suggests the plane may have turned back and crossed over the Malaysian peninsula.

In the scenario being discussed here, the "bad guys" would have to be the pilots, correct?

I can't see external hijackers or terrorists having the knowledge to do the things implied (manually accessing underfloor electronics, flying the maneuvers described, etc).

jyl, thats the impression I get from Jeff and fing's post. If that is the case then the pilots could have killed all on board without all the fancy flying without the transponder turned on.

If the pilots remained in control of the plane the entire time then why would it crash in the ocean? Or did it? I think that is the most likely end for it and has now sunken to the bottom of the ocean.

Fing, that's an interesting theory. I don't know how many failsafes the 777 pressurization system has, but if it allows the crew full manual control they could either simply disable the system or turn the cabin altitude high enough that everyone went to sleep. It could be relatively gradual if done that way.

Could it be sitting in a hanger somewhere? And the passengers could still be alive.
That would explain the mobile phones ringing but not answered.

This just gets more and more intreging. (With respect to the families affected)

Stupid theory I know but after what's happened who knows?

Taking into account that life can be stranger than fiction, the fact is that you can't just land a triple 7 just anywhere.......well, you can..... ONCE.

A long, strong runway is needed if you ever want to take off again and/or keep from killing all aboard. It would take some good planning and a damn good pilot......then there is the cover-up......

I can't imagine a 777 crashing into the ocean and there not being a lot of debri on the surface.

Sure they could have missed the debri but at some point they should find something.

Yeah, but you gotta look in the right place.....and the possible area is growing by the hour.

The whole world is looking for this plane? If its in a hanger it's in a country that is hiding it. If the people are alive, who's ordering food for 200 people for days on end. It would require a huge cast of characters to pull this off.


I think Malaysia is covering for the fact that they have no poor idea of what went on. I suspect that our military has a better idea of where it is...at least I hope so.

Personally, I'd like to think it wasn't the pilots. They seemed like stand-up guys.

Yes, the manual control of pressurization could be used to deflate the cabin, and kill the pax and crew. Time of useful conscientiousness at 40000 feet is about 6 seconds.

That sucks!

Don't the oxygen masks automatically deploy at loss of pressurization?

Once it is located (in what ever way presents itself), we will know what happened.

Emergency oxygen generators for pax only last for a few minutes. Once the generator is depleted, you can suck on that mask all you want until you pass out.

The pressure fed ox that the pilots use is a different system with more endurance. And as fing said, if you are not familiar with pressure fed air, it is "uncomfortable".

[Q] How many deliberate, pilot-caused crashes has the world had since 9-11?

I know here in the US, almost every foreign student pilot has to undergo a homeland security background check prior to receiving training. Obviously, the government knows that passengers are not the only threat to air safety.

And then there is my neighbor, who is just a f***ing idiot. If I got on a US Air flight and found out he was the pilot, I would demand to be let off the plane. Seriously. The guy is as unstable as a fat chick on a tightrope.

When it comes to terrorists....I wouldn't put anything past them. Such as whatever effort had to be made to learn how - not only to pilot a plane - but also to disable any electronics necessary to avoid detection. Unfortunately we found that out the hard way in 2001....

http://www.infowars.com/images2/ps/t...mphlet_who.jpg

http://img.wikinut.com/img/qpdo9pabc...hijackers.jpeg

Those are grainy pictures, but what do you see consistently in the eyes of those dead men?

A Kuala Lumpur to Beijing flight would have enough fuel to also go Kuala Lumpur to Karachi.
Just saying.