68.       
　　 The author of this editorial concludes that the guidelines for training pilots and maintaining equipment in the medical-helicopter industry are ineffective, even though they are far more stringent than those in other airline industries. To support this conclusion, the author cites statistics showing that the rate of medical-helicopter accidents is much higher than the rate of accidents for non-medical helicopters or commercial airliners. This argument is problematic in three critical respects.来源：考试大

      The first problem with the argument is that it rests on the unstated assumption that accidents involving medical helicopters have been due to inadequate pilot training or equipment maintenance. However, the author fails to acknowledge and rule out other possible causes of such accidents. In fact, common sense tells us that medical-helicopter accidents are most likely to result from the exigent circumstances and dangerous flying and landing conditions which typifymedical emergencies where helicopters are required to gain access to victims.来源：考试大

      A second, and related, problem is that the author unfairly compares the accident rate of medical helicopters with the accident rate for non-emergency aircraft. Medical helicopters are almost invariably deployed during emergencies to dangerous flying locales, whereas other types of aircraft are not. Consequently. medical-helicopter accidents will in all likelihood occur far more frequently than other aircraft accidents, regardless of pilot training or equipment maintenance.
来源：考试大
      A third problem with the argument is that the statistical evidence upon which it relies is too vague to be informative. The statistics concerning aircraft accidents may have been based on all types of accidents, whether minor or major. The statistics would be more meaningful if we knew that the accidents to which they refer were all of comparable severity. For all we know, the rate of casualty-causing accidents for medical helicopters is actually lower than for other aircraft. Additionally, we are not told the time period of the survey. An old survey or one that covered only a brief time period would be poor evidence in support of the author's claim.来源：考试大

      In conclusion, the author's evidence does little to support the conclusion. To be persuasive, the author must at the very least acknowledge and rule out other possible causes of accidents that are unique to the medical-helicopter industry, in any event, a more effective argument would be based on a statistical comparison of accident rates under differing sets of training and maintenance guidelines within :he medical-helicopter industry, not among different aircraft industries.