NTSB Factual Report

HISTORY OF FLIGHT

On June 21, 2011, about 1155 Pacific daylight time, a Bell 206B, N38EA, landed hard during a practice autorotation near Franklin Field Airport, Franklin, California. The helicopter was being operated by the California Department of Justice as a public-use, instructional flight. The solo student pilot was not injured; the helicopter sustained substantial damage during the landing, and was subsequently consumed by post impact fire. The flight departed Franklin at 1130. Visual meteorological conditions prevailed, and no flight plan had been filed.

The pilot reported that he initially departed in the helicopter from Sacramento Mather Airport, Sacramento, California, with the intention of performing pattern practice at Franklin. Upon arrival, he performed a series of straight-in autorotations, quick-stops, and low-hovers. He then performed two 180-degree autorotations to the left. He reported no anomalies with the helicopter during that period, and stated that all the maneuvers were uneventful.

Due to the direction of the traffic pattern, he was unable to practice 180-degree autorotations to the right. He therefore departed with the intention of continuing the maneuvers in a field 3 miles east of the airport.

The pilot chose a 50-feet-wide area, consisting of chest-high grass, where he practiced slope landings and pickups, and one uneventful 180-degree autorotation. He recalled that the temperature in the area was in excess of 100 degrees Fahrenheit. As he rounded the base leg for a second 180-degree autorotation, he confirmed all flight instruments were indicating normal engine operation, but noted his airspeed was too slow. He lowered the helicopter's nose, and the descent rate increased to about 1,800 feet per minute. About 100 feet above ground level (agl), he heard the low rotor warning horn, and immediately countered by quickly rolling the throttle to full power while applying up-collective. The helicopter then shuddered and vibrated, with accompanying, "snorting and popping sounds," that he had never experienced before.

He elected to perform a run-on landing rather than continue with the recovery. During the landing, the helicopter impacted the ground hard, spreading the skids. The right skid dug into the ground and separated, and the helicopter rolled onto its right side. He then shutdown the fuel supply and egressed as a fire erupted.

The pilot stated that the engine was still operating after he exited. The helicopter continued to burn for 2 more hours as fire crew attempted to gain access to the accident site.

PERSONNEL INFORMATION

A review of Federal Aviation Administration (FAA) airman records revealed that the pilot held a commercial pilot certificate with ratings for airplane single-engine land, and instrument airplane. He additionally held a private pilot certificate for airplane single-engine sea. The pilot did not hold a rotorcraft/helicopter certificate, but received an endorsement on October 15, 2010, to fly solo, and as pilot-in-command of helicopters in preparation for his practical test. He reported a total flight time in helicopters of 106 hours, with 62 in the accident make and model.

TESTS AND RESEARCH

The remaining sections of the helicopter, which included the engine, main rotor blades, tail rotor and associated gearbox were recovered for examination. Subsequent examination by an NTSB investigator did not reveal any anomalies with the airframe or engine that would have precluded normal operation. Refer to the engine and airframe report included in the public docket for further details.

NTSB Probable Cause

The student pilot's failure to maintain rotor rpm during the practice autorotation.