New details in the helicopter crash that killed four people near the Leesburg International Airport have been released. According to officials, the helicopter was in flight for a post-maintenance test flight, with a new water tank and snorkel installed to help firefighting operations. Ground testing and calibration were performed before the crash, which was the first flight after the STC was installed. The report said witnesses spotted the helicopter make six passes in front of the hangar at the airport and drop water that was picked up from a nearby lake. On the seventh pass, someone noticed the snorkel swinging and called air traffic control. Before the controller could contact the pilot to slow down and land, as requested by the employee at the airport, the helicopter transitioned to forward flight, gaining altitude and airspeed. The report said the employee noticed the snorkel violently swinging and heard a loud bang, which he assumed was the snorkel contacting the main rotor blades or tail boom. Pieces of the helicopter were then spotted separating as the helicopter began to spin and fall below the tree line when a loud explosion was heard. Another witness told officials she also saw the snorkel swinging and started to wave her arms to try to get the pilot's attention but he did not see her. Authorities found the helicopter in a heavily woody area, about 1,300 feet from a runway. The tail rotor section was found 78 feet from the main wreckage and one-half of a rotor blade was 600 feet away. Officials say debris was scattered throughout the area, including lodged in the tops of trees.