To solve problems of PMA's offline-work in the field of aircraft maintenance, the paper researches strategy of data processing in occasional connect mode is researched and a data accessing model of "occasional connect" is proposed .On the basis of the model, the paper expatiated the process of its implementation from two aspects which are the choice of long-term data cache and synchronization mechanism. The primary application proves that it can be adapted to complex network condition in the field and can greatly enhance the ability of aircraft maintenance support.