[KUALA LUMPUR] Whoever reached across the dimly lit cockpit of a Malaysia Airlines jet and clicked off a transponder to make Flight MH370 vanish from controllers' radars flew the plane into a navigational and technical black hole.

By choosing that exact place and time to vanish into radar darkness with 238 others on board, the person - presumed to be a pilot or a passenger with advanced knowledge - appears to have acted only after meticulous planning, according to aviation experts.

Understanding the sequence that led to the unprecedented plane hunt widening across two vast tracts of territory north and south of the Equator is key to grasping the motives of what Malaysian authorities suspect was hijacking or sabotage.