In-circuit test fixtures are built specifically for a given PCB design (unless they have removable pogo-pin cassettes), which is a limitation. However, they generally only cost hundreds of dollars and they can simultaneously connect with all of the test points on one side of the PCB.
Flying probe test systems are more flexible because they can be reprogrammed for an ever-changing variety of PCBs. But the machines cost tens of thousands of dollars and they have a limited number of probes, which can make them unsuitable for loading firmware into the boards.
#PCB Assembly #PCB Testing