Research Of The Optimization Of Aero-Engine Overhaul Cost

Engine is called as the "heart" of aircraft, if it fails in flight, then it will result in some serious consequences, therefore, it is necessary to make an overhaul when the engine runs for long time. The engine maintenance cost is very high, usually accounting for 35%-40% of the total aircraft maintenance cost, which can be up to 3 million dollars, even more. So, a suitable engine overhaul plan can not only save a lot of maintenance costs, but also can improve the engine's reliability and stability, extending the time on wing. There are many factors affecting the engine overhaul, such as life limit parts, performance degradation, blade damage, AD/SB etc. With using three different overhaul levels, both the performance degradation and the replacement of life limit parts-- the two main reasons of engine overhaul are considered in this paper. According to the V2500 world fleet data and eMMP(electronic Maintenance Management Plan), through setting the overhaul interval as an optimization variable and the overhaul cost per flight hour as an optimization goal, an optimization model of areo-engine overhaul cost is established.The genetic algorithm and the dynamic programming algorithm are used to solve this model. With the genetic algorithm, the overhaul interval and the overhaul level are set as a gene, and a suitable fitness function is used to simulate the rule of "survival of the fittest".After a lot generations of simulation, finally, an optimized engine overhaul plan can be get.With the dynamic programming algorithm, through setting recovery time of modules and life limit parts as the value of state, and applying the concept of stage and state transitions, an optimized engine overhaul plan can also be get. Comparing the two different results, both algorithms are proved that they are feasible and reliable for the engine overhaul cost optimization problem, which can provide a reference when the airlines make an engine overhaul program.