Malaysian Officials have concluded missing flight #MH370 was hijacked and steered off course

[whopis01]

81. Boeing (combined with regulations) says it is the pressurization limit

The maximum pressure differential the cabin pressurization system can supply is 8.6 psi. The maximum allowed cabin pressure altitude is 8000 feet. The pressure at 8000 feet is 11.2 psi. So the lowest outside pressure at which the cabin pressurization system could maintain 11.2 psi would be 2.6 psi. At 43,100ft the air pressure is 2.6 psi. So that altitude is right at the allowable limits of regulations and the capability of the pressurization system.

This comes from FAA regulations §25.841 - here is a link to it
http://www.ecfr.gov/cgi-bin/text-idx?SID=6950de6f84f12fb18c001de16a9b918a&node=14:1.0.1.3.11.4.180.71&rgn=div8

and performance guarantees for the 777 - section 6.5 is the relevant section
http://www.sec.gov/Archives/edgar/data/6201/000095012311037302/d81257exv10w2wg.htm

Most commercial passenger aircraft are physically capable of flying above their service ceiling - those ceilings are defined more by passenger safety issues than flight characteristics.

The 60k was a typo on my part - I meant to put 50k - and that was an extrapolation on my part from the climb rate curve. I probably should not have even included that in my previous post. My point was that the service ceiling is set by the pressurization system limits, not the flight characteristic limits.

I didn't mean for my post to be confusing - I certainly wasn't agreeing with the conclusion drawn in post 22 - I was trying to point out the logic that the other poster was attempting to use to get to that conclusion. They were making the leap (incorrectly) that once you crossed the pressurization limit the entire system would fail - which led them to an incorrect conclusion (in my opinion).