Abstract: Weft yarn faults encountered during the operation of rapier looms are corrected by correlating the detection of the fault to the angular position of the rotating main shaft of the loom. The loom has a shed with a giver side and a taker side, a giver rapier at the giver side and a taker rapier at the taker side. Position signals are stored in an electronic storage device for weft yarn faults which can occur at predetermined angular positions of the main shaft during operation of the loom. The weft yarn is monitored and a signal is generated when a faulty weft yarn is detected. This signal is compared with the position signals in a logic circuit to thereby determine the nature of the fault. After the nature of the fault has been determined, the faulty weft yarn is appropriately removed and, thereafter, weaving continues.