What was found
ANGLE OF ATTACK SENSOR P/N 861CAB, CHANNEL 2, SET UP WRONG. UNITS FITTED TO BOEING 757/767. A DEFECT HAS BEEN FOUND IN WORKSHOP TEST EQUIP THAT ALLOWED UNITS TO BE RETURNED TO SERVICE WITH CHANNEL 2 SET UP WITH A 180 DEGREE ERROR. AN OPERATOR RETURNED 2 ANGLE OF ATTACKS, BOTH PREVIOUSLY REPAIRED, FOUND FAULTY WHEN CHANNEL 2 SELECTED. INITIALLY, NO FAULTS FOUND WITH EITHER UNIT. INVEST REVEALED AN OPEN CIRCUIT ON CHANNEL 2 REF VOLTAGE FOR TEST EQUIP ANGLE PRECISION INDICATOR. ALL OPERATORS INVOLVED NOTIFIED OF OCCURRENCE. ALL UNITS, ANGLE OF ATTACK SENSOR P/N 861CAB, RELEASED TO SERVICE USING TEST EQUIP IN QUESTION SINCE LAST CALIBRATION HAVE BEEN RECALLED. (X)