Verify the complaint. Ask the driver then check the vehicle. Make sure the problem actually occurs by using an operationalcheck.
核实故障。询问驾驶员，然后再检查汽车。确定故障的确是由相关操作引起的。
2
An operationalcheck of each part or system operated by the crew while in flight to establish that, during flight, instrument readings are within normal range.
An operationalcheck of the trim, controllability, or other flight characteristics to establish that the production aircraft has the same range and degree of control as the prototype aircraft.