By now, pretty much everyone who reads the Internet or watches the news has heard about this incident. But for those who may not or for future reference, here are what details we know about the flight prior to its disappearance.
Malaysia Airlines Flight 370 headed to Beijing from Kuala Lumpur, locally at 12:41 am Saturday (Friday afternoon ET), March 8, 2014, air traffic controllers in Subang, outside Kuala Lumpur, lost contact with the Boeing 777 plane over the Gulf of Thailand between Malaysia and Vietnam, 90 nautical miles northeast of Kota Bharu, Malaysia. Malaysia Airlines’ Boeing 777 asset was last tracked at 1722 Zulu (1:22 am local), when it disappeared from radar contact. I've marked the approximate area on the map below.
The only other factor we know for sure is the aircraft attempted to "turnaround". It is unclear if this means a full 180 degree turn back to its point of origin or if it was a more abrupt 90 degree turn indicating a loss of altitude (and the turn is an attempt to avoid other aircraft in the route).
The first point many articles fail to point out is that aircraft operating under IFR aren't truly tracked by radar as in the beam reflected off of the skin of the aircraft, but rather but the transponder signal received by the radar antenna. It is the reason why the final location of the aircraft is alluding authorities. Once the transponder was turned off or destroyed, FL 370 disappeared from air traffic control radars. Any AWACS in the area would have been able to still track it as military radars look at both skin reflection as well as transponders.
The second point is the black box (which is actually a bright color such as red or orange so you can find it) emits a locating signal but that signal is very weak. The signal is only good for several thousand yards and that assumes it isn't underwater.
The third point is why didn't Malaysia Airlines Flight 370 squawk either "7500" for hijacking or "7700" for emergency? If the disappearance was due to some type of hijacking or terrorist incident, then the pilot and co-pilots may have been overwhelmed or killed before they could react. If not then a terrorist or hijacking, then there is the possibility something in the environment effected the crew before they could enter the transponder code. If oxygen levels slowly dropped, reaction times for the pilots may have prevented them from acting accordingly.
The fourth is the lack of debris. If Flight 370 exploded in mid-flight or crashed into the ocean, there should be signs of debris floating in the ocean. Seat cushions, life vests and baggage should be visible on the surface. Some speculate this is a sign that is was diverted and forced to land somewhere. This seems unlikely as it is damn hard to find land strips long enough for a Boeing 777 much less keep witnesses from seeing it. The only explanation that makes sense right now is that searchers aren't looking in the right place.
The Boeing 777 has operated for nearly 20 years with an impeccable record so it seems unlikely that the disappearance of Flight 370 is related to some type of mechanical failure. It is also unlikely that a missile was used to bring down the aircraft. Missiles leave smoke trails and radar signatures that would have been seen.
The turn would indicate the pilots suspected something but since they did not radio anything, it would support a scenario involving a hijacker. But if hijacked, why blow up the aircraft over the ocean once you already have control of it?
I suspect we may find out a new type of attack was used. Some type of either cyber or advanced weaponry. A cyber attack could have be launched against the Boeing's on-board systems rendering the pilots unable to control the aircraft or radio for help. It is not outside the realm of possibility especially if one of the people carrying a fake passport were involved. Flying over the ocean, the aircraft could have been hit with some type of advanced weapon from a ship or satellite that knocked out its navigation systems and radios. If I'm right, governments and militaries would be extremely reluctant for this information to get out. It would mean that any civilian airliner could be targeted (and potential even military aircraft).
What is most disconcerting to me is the timing. This happened right after Russia's move into the Crimea. It seems to me like someone (and not necessarily the Russians) wants to keep the world off balance.