The Learjet 23 was operated by the Lear Jet Corporation to transport a company official from Wichita, Kansas to Detroit, Michigan, USA. The company official remained in Detroit. Following a weather briefing, the crew filed an Instrument Flight Rules (IFR) flight plan for the return trip to Wichita. They estimated a time en route of 2:40 hours with 3:30 hours of fuel on board, and requested a cruising altitude of Flight Level (FL) 410. N804LJ departed on runway 03L at 19:25. At 1931 the flight reported level at FL 250. At 19:32 they were assigned a new frequency for communications with Cleveland ARTCC. The acknowledgement of the new frequency was the last transmission received from N804LJ. The aircraft entered a steep descent out of FL250 and impacted the ground near Jackson, Michigan. PROBABLE CAUSE: “A loss of adequate attitude reference resulting from AC electrical power failure under night, turbulent conditions.”