Engine ingestion of PAPI/VASI or other lights?
AP story I'm reading right now quotes PX to the effect that the plane touched down, and then veered to the right "as though the wing hit something" at the same time the engine erupted in fire.
Could have drifted in wind - could have made a wrong turn in the sandstorm(?). At any rate the engine came in contact with and swallowed something that didn't agree with it.
Or so it sounds to me based on the reported facts to date.