What happened
During a night air taxi cargo flight, the flight crew encountered difficulties with the crew intercom system. As the aircraft approached the airport, the crew initiated their descent at a distance later than normal. This late descent required a reduction in power to below 25 percent torque, which triggered the gear warning horn. The crew noted that the sound of the horn eventually became part of the background noise.
During the approach phase, the captain requested that the tower dim the runway lights. During this communication, the runway and approach lights went out, causing the crew to lose visual contact with the runway. While the captain was in the process of asking the tower to restore the lights, the first officer called for the "gear down, syncs off, speeds high, below the line" checklist.
The captain did not hear this callout, attributing the failure to hear the first officer to either the ongoing conversation with the tower or the existing intercom system issues. Consequently, the landing gear was not lowered. As the approach continued, the first officer encountered difficulty slowing the aircraft to the appropriate approach speed. The aircraft touched down on the runway with the landing gear still retracted. The aircraft then slid approximately 2,500 feet along the runway before exiting the left side of the pavement. There were no injuries reported.