2014. What happened to missing Malaysia Airlines flight MH370. Why Planes Vanish details how signals from the plane with 239 people aboard winked out over a period of eight hours after the plane took off.

Why Planes Vanish also explores proposals to adopt more satellite tracking for planes, to replace radar that covers less than 3% of the earth's surface. Radar reaches only about 200 miles from its antennas, leaving vast swaths of ocean unmonitored.

But satellites circle the world, although regulators would have to reach agreement on how tracking should work and airlines would have to adopt the costlier monitoring equipment.

As international groups debate those policies, Goglia says investigators will keep searching for the plane for weeks or years if it takes that to find it. Sooner or later, the secrets will be given up.

Film Duration: 53 min