A Beech 100 King Air, N411HA, sustained substantial damage during takeoff when it went off the departure end of runway 18 (5,500 ft by 100 ft, asphalt) at the Jeffersonville-Clark Regional Airport (JVY) in Indiana, USA. The pilot, copilot, and 8 passengers were not injured. The pilot reported that the airplane’s flight controls and engines were operating normally during the pre-takeoff check, and the elevator pitch trim was positioned in the “green” range. He stated that the airplane did not accelerate as quickly as he expected during takeoff roll. He pulled back on the control yoke to lift the airplane off the runway, but the stall warning vane sounded. The airplane was already near the end of the runway when the pilot attempted to abort the takeoff and the airplane went off the end of the runway. The pilot stated that he didn’t get “on” the brakes or put the propellers into reverse pitch. The pilot veered the airplane to the right to avoid an instrument lighting system (ILS) structure. The left wing hit the ILS structure, and the left main gear and nose gear collapsed with both propellers contacting the ground. The airplane skidded back to the left before stopping. Once the airplane stopped, the pilot opened the cabin door and assisted the passengers in evacuating the airplane. There was no post-crash fire. PROBABLE CAUSE: The pilot’s inadequate preflight planning, his decision to take off knowing the airplane was over its gross takeoff weight, and his failure to abort the takeoff after he realized that the airplane was not accelerating as expected, which resulted in a runway excursion.