Aviation Accident Summaries

Aviation Accident Summary NYC08LA052

Gainesville, FL, USA

Aircraft #1

N70035

ROBINSON HELICOPTER R22 BETA

Analysis

The pilot of the helicopter was under flight instruction to add a rotorcraft rating to his certificate and was on a solo cross-country flight. The helicopter had been in cruise flight for about 1 hour and 20 minutes when the pilot noticed an intermittent illumination of the "clutch light" and perceived a loss of altitude. The pilot "reset the circuit breaker" and increased collective to regain the lost altitude. He then perceived a loss of rotor rpm and slowly and continuously lowered the collective to maintain the rotor rpm in the normal operating range. When the helicopter reached approximately 150 feet above ground level, the pilot could no longer maintain rotor rpm and entered autorotation. During the descent, he selected an empty parking lot for a landing, where the helicopter landed hard, bounced, and then rolled over onto its side. He added that the engine was running before and after ground contact, and he did not report any deficiencies in the handling characteristics of the helicopter. Functional testing of the clutch assembly revealed that the rigging and operation of the assembly were within factory specifications, but the engagement cycle time exceeded the factory limit. The pilot stated that he "reset" the circuit breaker, and continued to adjust the collective pitch to regain altitude and rotor rpm. The emergency procedure listed in the Pilot's Operating Handbook directed the pilot to "pull" the clutch circuit breaker and land immediately.

Factual Information

HISTORY OF FLIGHT On December 4, 2007, at 1050 eastern standard time, a Robinson R22 BETA, N70035, was substantially damaged following a forced landing in Gainesville, Florida. The certificated private pilot was not injured. Visual meteorological conditions prevailed and no flight plan was filed for the solo instructional flight conducted under the provisions of 14 Code of Federal Regulations Part 91. The helicopter departed St. Petersburg-Clearwater International Airport (PIE) and was destined for Gainesville Regional Airport (GNV), Gainesville, Florida. In a telephone interview, the pilot stated he held a private pilot certificate, with a rating for airplane single and multi-engine land. He was obtaining flight instruction to add a rotorcraft rating to his certificate, and was on a solo cross-country flight. The helicopter had been in cruise flight for about 1 hour and 20 minutes when he noticed an intermittent illumination of the "clutch light" and perceived a loss of altitude. The pilot "reset the circuit breaker" and increased collective to regain the lost altitude. He then perceived a loss of rotor rpm, and slowly and continuously lowered the collective to maintain the rotor rpm in the normal operating range. When the helicopter reached approximately 150 feet above ground level, the pilot could no longer maintain rotor rpm, and entered autorotation. During the descent, he selected an empty race track parking lot for a landing, where the helicopter landed hard, bounced, and then rolled over onto its side. A witness working near the crash site watched the helicopter as it descended "awful quick." He said, "It looked like the blades were slowing down, like he was losing power on those blades." The witness stated that the helicopter landed hard, bounced, and fell over on its side. When asked about the engine noise, he said he couldn't hear the engine well because "it sounded like it was gliding." The pilot later reported to the Federal Aviation Administration (FAA) that he was in the vicinity of the race track to take photographs of a building site. He added that the engine was running before and after ground contact, and did not report any deficiencies in the handling characteristics of the helicopter. PERSONNEL INFORMATION According to FAA records, the pilot held a second-class medical certificate issued on May 10, 2006. The pilot reported approximately 1,350 total hours of flight experience, of which 745 hours was in multi-engine airplanes and 579 hours was in single-engine airplanes. He reported 27 hours of rotorcraft experience, all of which was in the Robinson R22. AIRCRAFT INFORMATION According to FAA and maintenance records, the helicopter had an airworthiness date of June 29, 2004, and had accrued 1,332 aircraft hours. The last 100 hour inspection was performed on October 21, 2007, at 1,304 aircraft hours. METEOROLOGICAL INFORMATION At 1053, the weather reported at Gainesville Regional Airport included clear skies with winds from 010 degrees at 7 knots. The temperature was 14 degrees Celsius, and the dew point was 3 degrees Celsius. WRECKAGE AND IMPACT INFORMATION Examination of photographs of the wreckage revealed that the helicopter appeared mostly intact. The damage was limited to the main rotor blades, the right side windscreen, and the bottom of the vertical stabilizer mounted on the tail. The flight controls all remained attached at the rotor head. There was wrinkling of the skin at the base of the pylon, and in the cabin roof aft of the pylon. After the accident, the helicopter's engine started immediately, and ran continuously without interruption. On December 18, 2007, a follow on examination of the helicopter by FAA inspectors revealed that the drive belts did not rest in the proper pulley locations. Battery power was applied, and functional testing of the clutch assembly revealed that the rigging and operation of the assembly were within factory specifications. However, the engagement cycle time on consecutive tests exceeded the 1-minute maximum by 19 and 22 seconds respectively. ADDITIONAL INFORMATION According to the Robinson R22 Pilot Operation Handbook, Section 3, Emergency Procedures, Warning/Caution Lights, Clutch, "If...the light flickers or comes on in flight and does not go out within 7 or 8 seconds, pull the CLUTCH circuit breaker, reduce power, and land immediately. Be prepared to enter autorotation. Inspect drive system for a possible malfunction."

Probable Cause and Findings

The pilot's failure to follow the published emergency procedure. Contributing to the accident was a malfunction of the clutch assembly.

 

Source: NTSB Aviation Accident Database

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