Compared with two years ago, flight control is now basically stable, the market is becoming mature, and customers who have not tried it will hardly do so. How can you see stability and reliability? Here we can use the "three look" trick. The "one look" is the company's production capacity, through 2019 annual output is at least 1000 sets of all kinds of technological processes, quality management and testing system, it can be basically smooth and sound. The "second look" is device screening. The industrial products above the need for "zero" management of product device screening is very important, and it is necessary to examine the company's device screening process, screening rate, and so on, to determine the stability of basic devices. The "three look" is test environment third. Flight control products belong to "zero tolerance" fault products, which needs to go through module level testing, product level testing and system level testing at least. Although the product form is flight control, it must go through the whole machine installation flight test and then disassemble and restore before leaving the factory. If you think the above test is normal, it is wrong! It needs a full examination.