If it did crash in the Indian ocean a week ago - any floating debris will have moves way off from the crash site - now we are back tracking along known ocean currents and fighting weather affects on the surface...

Then we have the problem of the Indian ocean being miles deep in places compared to several hundred feet in the south china sea area were they originally thought it went down.

And the beeper-beacon on the black box has power for a couple of weeks - already lost a week due to the inabilities of the Malaysian government. They didn't search the pilots house until yesterday!