By Petronella Sibeene WINDHOEK An intensive report on a civil aircraft accident that claimed the life of well-known pilot Doug Castleman says the crash could have been caused by distraction during autorotation. Autorotation is the process that involves the switching off or reducing of the engine power in order for the flying machine to descend and land safely without engine power. Yesterday, the Directorate of Aircraft Accident Investigations in the Ministry of Works, Transport and Communication released the report. “It appears that the pilot was distracted by the be-haviour and character of the aircraft during the initial stage of autorotation; as a result he unintentionally allowed the main rotor rpm to decay below the helicopter lift capability, resulting in a high rate of descent from which recovery was not possible,” the report reads. The 58-year-old Castle-man was flying a Robinson R22 helicopter that crashed during an instructional flight on Farm Narris northeast of Mariental. Based on details obtained from the senior aircraft accident investigator Ericsson Nengola, the student pilot who was under instruction stated that the instructor was demonstrating autorotation at the time of the accident. The instructor asked the student to switch off the governor while he was lowering the collective pitch lever down. Upon acting on instruction, the helicopter severely trembled but the late Castle-man managed to balance it. Shortly, the rate of descent increased uncontrollably resulting in a collision with the terrain at an extreme rate of descent. The findings reveal that the engine and rotor system were developing a significant amount of power at the time of impact. “The pilot tried to stop the descent but did not have control effectiveness and enough height to recover from the high rate of descent,” report added. Miraculously, the student survived the crash but sustained serious injuries to his back associated with high impact forces. Nengola confirmed that the survivor is still in Cape Town for treatment and is likely to return to Namibia next week. Practical autorotation continues to be the primary cause of accidents in the type of helicopter Castleman was operating. According to Nengola, the department investigated every aspect of the accident and the engine was sent to Pretoria in South Africa for further examination. Nengola said the accident analysis, conclusions and safety recommendations are neither to apportion blame nor single out any individual(s) but for prevention of future accidents. The findings further reveal that apart from the pilot being the holder of a valid airline transport pilot licence, the aircraft was maintained in accordance with the approved maintenance schedule. According to the report, “Examination of the wreckage and engine failed to disclose evidence of pre-impact failure or malfunctions prior to impact that could have caused or contribute to the accident.” It is recommended that an industry liaison meeting be held in conjunction with all helicopter operators and owners to discuss the characters and differences of helicopters. Aviation safety meetings are considered good forums for such discussions, the report says.
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