Aviation Accident Summaries

Aviation Accident Summary WPR13LA003

Rockport, WA, USA

Aircraft #1

N80140

ROBINSON HELICOPTER R22 BETA

Analysis

The pilot reported that while maneuvering, the helicopter’s clutch caution light illuminated. The pilot initiated a precautionary descent and began to slow the helicopter in an effort to locate a clearing in the trees. The clutch caution light was still on after 10 to 12 seconds, so the pilot instructed his passenger to pull the circuit breaker. The pilot spotted a clearing, and shortly thereafter the low rotor rpm warning light illuminated and the horn sounded. The pilot lowered the collective and headed for a landing spot. About 20 to 30 feet above ground level, the pilot flared the helicopter and used the remaining collective control input the last 3 to 5 feet. The helicopter subsequently landed hard in high brush surrounded by tall trees. During the postaccident examination, bench testing of the clutch actuator revealed that the actuator operated normally and within specified limitations. Further examination of the actuator motor found no anomalies that would have precluded normal operation. The reason for the illumination of the clutch light could not be determined.

Factual Information

On October 3, 2012, about 1340 Pacific daylight time, a Robinson R22 Beta helicopter, N80140, sustained substantial damage during a hard landing approximately 32 nautical miles north of Rockport, Washington in the North Cascades National Park. The pilot and passenger were not injured. The helicopter had substantial damage to the tailboom and fuselage. The helicopter was registered to Emerald City Aircraft Leasing and operated by Glacier Aviation Inc., of Burlington, Washington, under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the local flight, and no flight plan was filed. The flight originated from Skagit Regional Airport, Burlington, Washington about 1230. The pilot reported that while maneuvering the clutch caution light illuminated and stayed on steady. The pilot initiated a descent and began to slow in an effort to locate a clearing in the trees. The light was still on after 10 to 12 seconds so the pilot instructed his passenger to pull the circuit breaker. A clearing was spotted and shortly thereafter the low rotor RPM warning light illuminated and the horn sounded. The pilot lowered the collective and headed for a landing spot. The pilot flared about 20 to 30 feet and utilized collective control the last three to five feet. The helicopter subsequently landed hard in high brush surrounded by tall trees. A National Park Service representatives video taped the accident site on October 15, 2012 and sent to the National Transportation Safety Board, investigator-in-charge. The videos show the helicopter in high brush surrounded by tall trees. The video revealed the separation of the tailboom and damage to the tail rotor blades. The fuselage was buckled in several areas. The wreckage was relocated to a secure facility for further examination. A follow-up examination of the wreckage was conducted and revealed that more of the fuselage was buckled. The left skid assembly was damaged and the rear cross-tube was bent. The drive belts were tight and properly positioned on both the upper and lower sheaves. The condition of the drive belts were unremarkable. The upper sheave had light marks along the outer circumference of the upper sheave. The drive belt contact areas on both sheaves were unremarkable. The clutch actuator was found in the extended position. The exposed actuator shaft was about 1 1/2 inches in length. The down limit screw was extended about 3/4-inches below its support bracket. The clutch actuator was operated from the ‘Disengaged’ to ‘Engaged’ switch positions. During the actuation of the clutch actuator the actuator motor made a noise that was not consistent in tone and had intermittent squealing throughout the actuator’s full range of travel. The actuator moved in both directions from stop to stop. No other anomalies were noted. The clutch actuator was removed and examined at the facilities of the Robinson Helicopter Company. The actuator was installed on test benches and operated normally and within limits. The actuator was disassembled and no anomalies were noted. The actuator motor was removed from the actuator and disassembled. The wiring grommet was damaged and was found in two parts. The magnets were removed and dusting was visible on the interior side of both magnets and on the rotor. The brushes and commutator showed signs of normal operation. The electrical cap assembly had dusting near the commutator area. The bearing on the output shaft side felt slightly rough when rotated by hand. No other anomalies were noted.

Probable Cause and Findings

The pilot's failure to maintain sufficient rotor rpm during a precautionary landing, which resulted in a hard landing.

 

Source: NTSB Aviation Accident Database

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