Losing all power doers not result in a nose-dive. Handled correctly, the airplane just becomes a glider.

Several possibilities here...

- The news media may have got it all wrong. This is EXTREMELY unlikely and has probably never actually happened in recorded human history, but it's theoretically possible so I thought I'd throw it out there

- The pilot may have tried to glide to a landing spot that was simply too far away. As the airplane sinks towards the ground and it looks like it's going to land short of the desired spot, an inexperienced pilot may have a tendancy to pull the nose back to "stretch" the glide. This doesn't work without an engine, and the airplane will soon stall at low altitude, causing the nose to drop and the airplane to plummet, resulting in a nose-down crash.

- The airplane landed in a normal attitude on a soft surface, but the nose wheel sunk in causing the airplane to pitch forward on the nose. This one is usually survivable though.