History of Flight
On August 28, 2014, at about 1055 Pacific daylight time, an Airbus Helicopters AS 350 B3, registration N991SD, landed hard and rolled onto its left side at Hemet-Ryan Airport in Hemet, California. The Riverside County Sheriff's Department (RCSD) operated the helicopter under 14 Code of Federal Regulations Part 91 as a local instructional flight. The deputy flight instructor (FI) and deputy private pilot under instruction (PUI) sustained minor injuries. The helicopter departed Hemet about 1040 in visual meteorological conditions; no flight plan was filed.
The FI reported that he and the PUI initiated a simulated governor failure at 500 feet above ground level by switching the auto/manual switch to manual. They flew an extended left downwind to runway 23 for 2.5 miles, turned base, and then final approach, reducing throttle input. As the helicopter descended through 50 to 100 feet, the FI noticed rotor rpm decreasing more than expected. He attempted to increase throttle but did not gain additional rpm. At about 50 feet, the descent rate increased and rotor rpm continued to decay. Despite pulling aft cyclic and lowering the collective, rpm did not recover. The FI felt resistance when moving the cyclic forward. The helicopter impacted the runway hard, spun left 180 degrees, and came to rest on its left side facing northeast. The FI noted previous instances of cyclic restriction in this helicopter model.
Personnel Information
The 44-year-old FI held a commercial pilot certificate with ratings for airplane single-engine land, single-engine helicopter, and instrument airplane, along with a flight instructor certificate for airplane and helicopter. He held a second-class medical certificate with the limitation that he must have glasses available for near vision. He had 2,542 total flight hours, including 1,973 hours in the accident make and model.
The PUI held a private pilot certificate with a single-engine helicopter rating and a second-class medical certificate requiring corrective lenses. He had 259 total flight hours, with 77 in the make and model.
Aircraft Information
The helicopter was a Eurocopter AS350B3, serial number 3325, with a total airframe time of 6,312 hours. It was maintained on a continuous airworthiness program, with the last inspection on July 25, 2014. The Turbomeca Arriel 2B engine, serial number 22151, had 6,026 total hours and 2,526 hours since overhaul.
Examination and Tests
Investigators from the NTSB, FAA, Eurocopter, and Turbomeca examined the wreckage on September 19, 2014. No mechanical anomalies were found in the airframe or engine. Main rotor to free turbine continuity was established, as well as tail rotor drive continuity. Cyclic control continuity was established but stiff due to binding near the rotor mast; the fore/aft push/pull rod under the cabin floor had a small upward dent. The cyclic friction was set to midrange. The collective was also stiff from binding near the mast area, and the right side collective head was damaged from impact. The throttle rolled freely with no binding. The gas generator and free turbine turned freely, and transmission continuity was confirmed. The pilot helmets were scratched and abraded and were taken out of service.
Post-Accident Actions
Following the accident, RCSD sent the PUI to an outside vendor to complete his commercial pilot certificate. RCSD implemented a computer-based Safety Management System (SMS), mandated yearly factory simulator training for pilots, and began sending pilots to Airbus Maintenance Test Pilot courses. RCSD purchased helicopter-rated helmets, and the safety officer organized a yearly safety stand-down.