Lockheed Martin's Sikorsky subsidiary has found that issues associated with the flight control software caused the Aug. 2 hard landing incident involving the S-97 Raider aircraft prototype, Vertical Magazine reported Monday.
The incident occurred as the prototype carried out a vertical take-off operation at the start of the test flight at the company's flight center in Florida.
Sikorsky released its findings after National Transportation Safety Board issued its initial report on the incident, which did not result in significant injuries to two flight crew members.
“In fly-by-wire helicopters, there are transitions in the flight controls that happen during the event, and in our analysis of the [hard landing], that transition didn't go exactly as it should, and we're making some changes to the flight control system software to accommodate that and ensure that it never happens again,“ Chris Van Buiten, vice president of Sikorsky's innovations business, said in a conference call.
Van Buiten said Sikorsky has been using the Raider prototype to advance the X2 demonstrator for the military's Future Vertical Lift helicopter program as well as a “risk reducer“ platform for the SB-1 Defiant aircraft.
Sikorksy partnered with Boeing to develop the SB-1 Defiant coaxial rotorcraft for the U.S. Army's Joint Multi-Role Technology Demonstrator program.
Van Buiten noted that Raider's flight software shares same features with that of Defiant and that both companies continue their analysis to determine whether to modify the rotorcraft's software.