Pings without debris. Sounds a bit odd--you'd think there'd be fragments of seat cushions and carbon fiber floating around a wide area surrounding the pings.
Not necessarily. If the plane came down intact, nose first, it would leave a comparatively small debris field. Think EgyptAir 900. U.S. units were on the scene the next day and they didn't find a very large debis field. The most noticable evidence was the smell of the jet fuel on the water. Most of the wreck and just about all the remains wound up on the ocean floor. In this case after three weeks what debris and fuel that had been on the surface would have disbursed in the rough waters of the area.