That's what I see when I play back the FlightRadar24 feed (not 750 feet!).
If this other report of the pilot requesting a climb on his last transmission is true, then that's also consistent with weather avoidance. An A320 loaded with only passengers and their luggage is operating at a fairly light weight, and is likely capable of climbing up to 36,000 feet, at least, if they needed to do it. That would be consistent with attempting to clear the tops of the cells, to stay out of turbulence, and to stay visual with the active cells to avoid them.
As I understand it ...
The flight was supposed to be about two and a half hours long. ATC lost contact about an hour before it was due to arrive. It’s been “missing” for about 5 hours.
Doesn’t look good.
As you can see from this portion of the Wikipedia entry on AF447, the A320 (the one that just disappeared) also has a history of pitot-related issues, dating to 2007 at Air France.
So have the A320's in the Air Asia fleet been modified with the recommended Airbus modifications? Was there an airworthiness directive, or similar directive to replace the defective systems, and if so, did Air Asia comply with it? So far it looks like QZ8501 was flying in similar circumstances to AF447; that is to say at cruise near thunderstorms.
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Pitot tubes
After May 2008, nine previous incidents involving the temporary loss of airspeed indication appeared in the Air Safety Reports (ASRs) for Air France's A330/A340 fleet. All occurred in cruise between flight levels FL310 and FL380. The first problem was reported on May 2008 and the latter two on March 2009, one of them the first event on an A330. Further, after F-GZCP accident, Air France has identified six additional incidents which had not been reported on ASRs. These were intended for maintenance Aircraft Technical Logs (ATLs) drawn up by the pilots to describe these incidents only partially, to indicate the characteristic symptoms of the incidents associated with unreliable airspeed readings.[163][164] The problems primarily occurred in 2007 on the A320 but, awaiting a recommendation from Airbus, Air France delayed installing new pitot tubes on A330/A340 and increased inspection frequencies in these planes.
http://en.wikipedia.org/wiki/Air_France_Flight_447