The National Transportation Safety Board (NTSB) last week released a preliminary report on the helicopter crash on the Fort McDowell Yavapai Nation on April 16 in which the pilot and a passenger were killed.

The report offers no indication relating to the cause of the crash at this point, but does provide details related to the activity leading up to and purposes for the flight.

The flight was to evaluate developmental main rotor blades that had been installed on the helicopter, the report states.

The test was scheduled for two legs of a flight out of Falcon Field in Mesa. It departed on the first leg at 5:45 a.m. and returned about 6:20 a.m. The helicopter sat on the ramp in an idle while 100 pounds of ballast were added. They departed for the second phase of the test flight at 6:32 a.m.

“The test flight legs consisted of multiple autorotations at maximum gross weight involving a simulated loss of engine power,” the report states. “The accident flight was the last test flight of the main rotor blades before the certification process.”

The test flight was being conducted by Tempe based Van Horn Aviation related to a new rotor design.

A witness walking along Fort McDowell Road about one-third mile from the accident site reported hearing a loud bang and then saw the helicopter falling from the sky. It was videotaped by the witness.

Investigators reported the debris field from the crash was about one-mile long and 1,000 feet wide.

The helicopter was a Bell 206 manufactured in 1981 and had a Rolls-Royce 250-C20B engine. It was registered to the current owner, TRE Aviation Corporation in January this year.

The pilot was identified as Rucie Moore, an experienced pilot and helicopter instructor for Embry-Riddle University Prescott campus and a test pilot. The passenger was identified by Van Horn Aviation of Tempe as Stephen Estes, an engineer with that firm. A statement on the VHA website identified Estes as the company’s engineering chief who was instrumental in the design and analysis of the new rotor blades.