Accident
On January 8, 2008, at 1623 eastern standard time, a Robinson R22 Beta, N179SH, was substantially damaged during a forced landing in North Palm Beach, Florida. The certificated student pilot was seriously injured. Visual meteorological conditions prevailed, and no flight plan had been filed for the flight from Witham Field (SUA), Stuart, Florida, to Fort Lauderdale Executive Airport (FXE), Fort Lauderdale, Florida. The solo instructional flight was conducted under 14 Code of Federal Regulations Part 91.
Pilot Report
According to the student pilot, he was on the return leg of a cross country trip. After first landing in Stuart, he confirmed the fuel quantity without reducing rpm. Before taking off again, he performed preflight checks, including a magneto check, sprag clutch check, carburetor heat check, and low rotor rpm check. With all warning lights out and all gauges "in the green," he departed toward Fort Lauderdale.
The student pilot reported that he was transitioning south along the beach at 500 feet and 80 knots. He had just received a discrete transponder code from the West Palm Beach Air Traffic Control Tower, when the helicopter appeared to lose power. The student pilot raised the collective, but the situation "worsened," and he noticed a slight yaw. He then lowered the collective and turned the helicopter left, into the wind. He subsequently completed an autorotation into the surf.
The student pilot noted that prior to the loss of engine power, he did not notice any unusual vibrations or noises, but did notice a "significant loss of power which resulted in an immediate loss of altitude." He also noted that it felt like "the sinking and yawing one experiences when settling with power."
Recovery and Damage
The helicopter came to rest upright on top of a coral reef, initially about 40 feet from the shoreline. With a rising tide, the helicopter became submerged up to the main rotor mast.
The helicopter was subsequently recovered to the operator's facility. Removal from the water revealed that the skids were spread, the fuselage was crushed upward, and the pilot's seat structure was collapsed downward. The main rotor blades remained attached, but buckled spanwise, and the tail rotor blades were fractured. The Lycoming O-360-series engine remained attached to the airframe and did not exhibit any external evidence of malfunction.
Engine Examination
On January 16, 2008, an FAA inspector and a Lycoming air safety investigator decontaminated the engine by draining the oil sump, and removing the spark plugs and valve cover to purge water. The engine was then flushed with jet fuel, and penetrating oil was sprayed into the cylinders to stave off corrosion.
On January 22, 2008, the FAA inspector, with the Lycoming air safety investigator, examined the engine and found no preaccident mechanical anomalies that would have precluded normal engine operation. In addition, "aviation fuel" was found within all lines and components forward of the gascolator. Spark plugs were examined and "exhibited combustion deposits consistent with normal operation." The FAA inspector also stated that the helicopter's drive belts were in place, and he did not note any preaccident mechanical anomalies with the helicopter.
Weather
Weather, recorded at a nearby airport at 1653, included a few clouds at 4,000 feet, winds from 090 degrees true at 9 knots, temperature 23 degrees Celsius, dew point 13 degrees Celsius, and an altimeter setting of 30.17 inches Hg. Using the ambient temperature and dew point, a carburetor icing probability chart produced by the National Research Council of Canada indicated a probability of "serious icing at glide power," while another chart in the FAA's Tips on Winter Flying pamphlet indicated that carburetor icing conditions bordered between "serious icing - glide power" and "light icing - glide or cruise power."