中文摘要：

远程巡航方式和经济巡航方式均是常用的飞行方式，经济巡航方式可以降低整个飞行成本，但航空公司目前很难将该方式下节省的时间成本准确计入，因此远程巡航方式成为当前条件下最为经济的巡航方式。研究了在远程巡航方式下成本指数的计算方法，分析了飞机质量、高度和温度对该成本指数的影响，并根据QAR记录数据进行了验证计算，证明其节油效果明显，具有良好的应用价值。

英文摘要：

Long range cruise and economic cruise are the common flight models. Adopting economic cruise model can decrease the flight cost,but it is difficult for the airlines to calculate saved time-cost accurately now. So long range cruise is the most economic cruise model at present. This paper studies the method to calculate the long range cruise （LRC） cost index,analyzes the influence of aircraft weight,altitude and temperature to the cost index,and contrasts the results with what calculated by QAR data. The analysis in the paper clearly shows that long range cruise has a tangible result for fuel saving and a good value for application.