What happened
The accident occurred on a dark night under CAVU (Ceiling and Visibility Unlimited) weather conditions. The captain directed the first officer, who was acting as the pilot flying, to disarm the landing gear warning horn system by pulling its associated circuit breaker. The first officer complied with this instruction and did not challenge the captain's decision.
During the final approach phase, the first officer issued a command to lower the landing gear but failed to verify that the action had been completed. Simultaneously, the captain forgot to manually lower the gear. As the aircraft touched down, it slid to a stop on its belly. The impact caused the three propeller blades of the right engine to fragment. These fragments punctured the passenger compartment.
Two passengers seated in row 2, directly abeam the plane of rotation for the damaged propeller, were struck by the debris. They sustained serious lacerations to their legs and minor facial lacerations as a result of the incident.