I was watching yahoo news and the Malaysia authorities both civilian and military were discussing the disappearance of Flight 370. Even if the plan was hijacked, radio out and/or emergency the pilot can change the mode 3 code.
Even it the transponder was turned completely off, the civilian and military radar will pick a blimp on the radar as a signature, indicate control lost from that point and follow that radar signature. If the plane exploded and/or hit by missile or whatever, some form of pattern would shown up on radar.
If the plane happen to land elsewhere, someone on the ground would be chatting via some form of communications as to why a Boeing 777 is here.
If the plane did crash land in open water, the black box would transmit a locator beacon.
Remember TWA 800 off the Atlantic exploded in 1996, it left debris in the ocean.
I found this from natural news.
• Fact #1: All Boeing 777 commercial jets are equipped with black box recorders that can survive any on-board explosion
No explosion from the plane itself can destroy the black box recorders. They are bomb-proof structures that hold digital recordings of cockpit conversations as well as detailed flight data and control surface data.
• Fact #2: All black box recorders transmit locator signals for at least 30 days after falling into the ocean
Yet the black box from this particular incident hasn't been detected at all. That's why investigators are having such trouble finding it. Normally, they only need to "home in" on the black box transmitter signal. But in this case, the absence of a signal means the black box itself -- an object designed to survive powerful explosions -- has either vanished, malfunctioned or been obliterated by some powerful force beyond the worst fears of aircraft design engineers.
• Fact #3: Many parts of destroyed aircraft are naturally bouyant and will float in water Some parts and even passenger(s) stuff will come to the surface.
In past cases of aircraft destroyed over the ocean or crashing into the ocean, debris has always been spotted floating on the surface of the water. That's because -- as you may recall from the safety briefing you've learned to ignore -- "your seat cushion may be used as a flotation device."
Yes, seat cushions float. So do many other non-metallic aircraft parts. If Flight 370 was brought down by an explosion of some sort, there would be massive debris floating on the ocean, and that debris would not be difficult to spot. The fact that it has not yet been spotted only adds to the mystery of how Flight 370 appears to have literally vanished from the face of the Earth.
• Fact #4: If a missile destroyed Flight 370, the missile would have left a radar signature
One theory currently circulating on the 'net is that a missile brought down the airliner, somehow blasting the aircraft and all its contents to "smithereens" -- which means very tiny pieces of matter that are undetectable as debris.
The problem with this theory is that there exists no known ground-to-air or air-to-air missile with such a capability. All known missiles generate tremendous debris when they explode on target. Both the missile and the debris produce very large radar signatures which would be easily visible to both military vessels and air traffic authorities.
• Fact #5: The location of the aircraft when it vanished is not a mystery
Air traffic controllers have full details of almost exactly where the aircraft was at the moment it vanished. They know the location, elevation and airspeed -- three pieces of information which can readily be used to estimate the likely location of debris.
Remember: air safety investigators are not stupid people. They've seen mid-air explosions before, and they know how debris falls. There is already a substantial data set of airline explosions and crashes from which investigators can make well-educated guesses about where debris should be found. And yet, even armed with all this experience and information, they remain totally baffled on what happened to Flight 370.
• Fact #6: If Flight 370 was hijacked, it would not have vanished from radar
Hijacking an airplane does not cause it to simply vanish from radar. Even if transponders are disabled on the aircraft, ground radar can still readily track the location of the aircraft using so-called "passive" radar (classic ground-based radar systems that emit a signal and monitor its reflection).
Thus, the theory that the flight was hijacked makes no sense whatsoever. When planes are hijacked, they do not magically vanish from radar.
Learn more: http://www.naturalnews.com/044244_Malaysia_Airlines_Flight_370_vanished.html# #ixzz2vaBT8pVN