A Sikorsky S-97 Raider crashed at 07:30 on 2 August at the company’s flight test center in West Palm Beach, Florida, the Lockheed Martin company says.
Few details of the incident were immediately available.
Local news photographs taken from a distance appear to show the compound helicopter prototype sitting on a runway with landing gear retracted.
Sikorsky says two crew members on board the S-97 escaped a hard landing without injury.
The S-97 was in a hover during a test flight when the incident occurred, Sikorsky says.
The aircraft features coaxial, rigid rotors and a variable-pitch pusher propeller, a configuration designed to achieve speeds higher than 220kt in level flight.
Sikorsky launched the prototype with a $200 million investment in October 2010, as the US Army then pursued a replacement for the Bell Helicopter OH-58D Kiowa Warrior.
The army retired the OH-58D fleet two years ago without a replacement. But the S-97 remained useful as a testbed for the high-speed Sikorsky-Boeing SB-1 Defiant, a demonstrator and candidate for the army’s Future Vertical Lift acquisition programme.
Both the S-97 and SB-1 are based on technology developed by the X2, a proof-of-concept that set a new speed record for a compound helicopter using the coaxial-rotor/pusher-propeller configuration.
In a statement released after the hard landing, Sikorsky did not comment on the future of the S-97 programme, but instead referred to the fundamental X2 technology.
“We fully intend to continue advancing the X2 technology,” Sikorsky says.