Fort Stockton, TX, USA
N993KC
ROBINSON HELICOPTER R22 BETA
The single-engine helicopter experienced a hard landing after a malfunction of the belt drive system for the main rotor. The pilot had just taken off from a trailer and had transitioned to low level cruise flight when he heard a loud bang. The pilot cross-checked his engine instruments and observed the engine RPM was excessively high and the rotor RPM was below 80 percent, accompanied by the low rotor RPM warning. The pilot then initiated an autorotation and landed hard with near zero forward speed. The aircraft bounced backwards after initial impact and came to rest in the upright position. The on-scene investigation noted that one of the v-belts to the main rotor drive system had separated which caused the other belt to slip off the upper spindle. The reason for the separation could not be determined.
On September 12, 2007 at 1438 central standard time N993KC, a Robinson R22 Beta helicopter, experienced a hard landing after a malfunction of the belt drive system for the main rotor. The pilot received serious injuries and his passenger received minor injuries as a result of a hard landing. The pilot had just taken off from a trailer and had climbed to about 50 feet above ground level to conduct a predator control mission about 10 miles northwest of Fort Stockton, Texas. The flight was conducted in visual meteorological conditions under 14 Code of Federal Regulations, Part 91. In an interview with the pilot, a Federal Aviation Administration (FAA) inspector stated that the pilot had just transitioned to a low level cruise after takeoff when he heard a loud bang and felt a vibration in the pedals. He observed the engine rpm was excessively high and noticed the rotor RPM was below 80 percent accompanied by the low rotor RPM warning. He then lowered the collective and searched for a location to make an emergency landing. The pilot then initiated an autorotation, was not able to recover the rotor RPM, and landed hard with near zero forward speed. The aircraft bounced backwards after initial impact and came to rest in the upright position. An FAA inspector conducted an on scene investigation and noted that one of the v-belts to the main rotor drive system had separated which caused the other belt to slip off the upper spindle. The pilot stated the clutch light was operating normally prior to takeoff. Weather reported at 1411 central daylight time at Fort Stockton (KFST), 10 miles north west of the accident site, was winds 110 degrees at 9 knots, 10 miles visibility, scattered clouds at 2100 feet and 2600 feet, temperature 24 degrees Celsius, dew point 18 degrees Celsius, and an altimeter reading of 30.11 inches of Mercury.
The failure of the v-belt drive system to the main rotor for undetermined reasons. Contributing to the accident was insufficient altitude to perform a successful autorotation.
Source: NTSB Aviation Accident Database
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