http://www.weathergraphics.com/tim/af447/

http://trueslant.com/milesobrien/2009/06/08/the-coffin-corner-and-a-mesoscale-maw/

Hard to believe in this day and age, but when you are flying over the pond, you are pretty much on your own. You are not talking to air traffic controllers or being painted by their radar – and of course there are no weather reporting stations beneath you. By definition, thunderstorms are unstable, dynamic and fast-moving. So by the time they reached the storms – more than four hours into the flight – what they learned in the pre-flight briefing was yesterday’s news.
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Weather Radar – from NASA

As a result, flight crews rely heavily on the weather radar bolted onto the nose of the airplane. It is a very useful safety device but interpreting its display is a bit of a black art. A lot of pilots, frankly, do not fully understand the intricacies of its capabilities and limitations. It is akin to a blind man with a cane; he can tell something is in his way, but he doesn’t see it.

For instance, the radar mostly detects rain and hail – and if that first layer of storm cells was particularly heavy, it might have acted like a curtain – hiding the reinforcements from radar beams. With the benefit of hindsight (and satellite imagery captured at the time of the crash), we know now there were at four more layers of strong storms behind the first line of cells. And radar cannot detect the strong updrafts of warm air that feed a thunderstorm…

The only land based communications that work are HF radio, (common VHF aircraft COMs are line of sight as is cell service) the usable frequency band depends on the MUF (time of day, season dependent).

GPS is a receive only process, your NAV equipment has to retransmit your location somehow for it to be usable by third parties to find you, and they need to be listening and have recorded the last known transmission. Upon system failure, you may still travel quite some distance before hitting the water.

The aircraft has on-board weather radar that helps avoid flying into active thunder storm cells. The area they were flying through (equatorial zone) can have such density of storm activity that you essentially can fly into a box canyon of storm cell activity.

Some indications show that the current Pitot/Static systems on this aircraft have icing problems. Your flight data systems depend on the pitot pressure to determine airspeed. Your controls are “fly by wire” and if anything disrupts the multiple-redundant system that flies the plane including getting bad flight data from instruments while under manual control, you are in it deep. See the Guam B-2 accident video to see what happens when water flows to a low point in the pitot/static system and freezes. http://www.youtube.com/watch?v=M9hb-OutGAY

The flight data recorders may be as much as 3 miles down under water.

Yes, you can get lost without trace in the middle of the ocean, despite all the modern tech equipment and the best way of finding you will be last known transmissions if it can be triangulated, or if it had location data and then correlating that to known ocean currents, and then start looking for debris.

To find the aircraft, current direction, speed and time elapsed need to be taken into consideration to back track to where the plane possibly entered the water.

It all resolves to a rather large area of real estate.

David wrote:

But it flies in the face of common sense to allow a planeload of people to deal with 100 mph updrafts, no matter how well designed the plane is. If information was not complete I can understand, but it it is humans challenging nature then it is not only stupid, but irresponsible and downright arrogant!

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Flight crews are trained to avoid areas of weather, and advanced weather radars aboard the aircraft are designed to aid in that effort. However, nature is unpredictable, and some hazards can’t been seen on radar. As a case in point, an airliner was torn apart near Mt. Fuji in Japan on a wonderfully clear day in the fierce turbulence generated by the winds around the peak. Any form of transport has its risks, and there is only so much that can be done to reduce them.