What happened on Malaysia Airlines flight 370? All was well for that 1st hour. When the co-pilot said good night he meant it.
Shortly after that the fire in the electrical system under the cockpit knocked out all communications equipment. The fire started when the batteries malfunctioned. That combined with lax maintenance, shut down all systems.
The pilot had just enough time to program the autopilot "George" to fly in the direction of the nearest airport, before losing consciousness. Within minutes the fire burnt a hole in the fuselage, causing rapid decompression, and killing everyone on board.
With the fire extinguished due to the blast of cold air, the plane kept flying until it ran out of fuel 7 hours later.
The plane went down in the deepest ocean and the black boxes may never be found.