Most flying probe testers conduct signal integrity testing on populated boards, test open pins on ICs, and measure resistor and capacitor values, as well as check for shorts and opens on inductors, diodes, MOSFETs, relays, and transformers.
Flying probe can be performed without an expensive fixture, as mentioned above. Four to eight test heads move across the PCB under test at high speed. Electrical probes located on each head make contact and test device vias and leads on the board to provide sequential access to the test points. These probes are electro-mechanically controlled and move as precisely as within a few mils. Flying probe testers are categorized as an in-circuit test (ICT) system or manufacturing defects analyzer (MDA).
Flying probe is often used to validate line set-up without the cost and cycle time related to designing and building traditional bed-of-nails fixtures. Hence, flying probe can provide fast turn-around and high fault coverage benefits, but without the test fixture cost, which can sometimes run into outrageously high numbers.