N98F

the operator’s failure to adequately inspect the former military turbine powered helicopter, which allowed an engine issue to progress and result in a loss of engine power and a subsequent loss of control after the helicopter struck powerlines during a forced landing. Also causal to the accident were the following: 1) the Federal Aviation Administration’s (FAA) inadequate inspection and maintenance standards for former military turbine powered aircraft operating with an experimental exhibition airworthiness certificate; 2) the operator’s use of those standards instead of more rigorous standards, which were readily available to the operator and previously used to inspect and maintain the helicopter; and 3) the FAA’s inadequate oversight of the operator, which did not detect the inherent risk associated with the operation.