What was found
DURING A LANDING GEAR FUNCTIONAL CHECK, THE GEAR UP/POWER REDUCED WARNING HORN, FAILED TO SOUND WHEN THE FLAPS WERE EXTENDED TO 25 DEGREES, SECOND NOTCH. THE MAINTENANCE TECH BELIEVED THIS WAS CAUSED BY THE FLAP POSITION MICROSWITCH BECOMING MISADJUSTED, SO HE REMOVED THE CABIN FLOOR TO GAIN ACCESS TO THE FLAP CONTROL SYSTEM. WHEN THE FLOOR WAS REMOVED, THE TECH OBSERVED THAT THE MICROSWITCH WAS NOT ACTIVATING BECAUSE THE FLAP CABLE HAD FRAYED MORE THAN 50 PERCENT OF ITS THICKNESS, CAUSING THE FLAP CONTROL SYS AND MICROSWITCH TO BECOME IMPROPERLY RIGGED. INSPECTION OF THE REMOVED CABLE REVEALED 4 OF THE 7 WIRE BUNDLES HAD BROKEN AND WAS SEPARATED IN A BROOMSTRAW PATTERN AT THE TURNBUCKLE SWAGE. THERE WAS NO EVIDENCE OF DAMAGE FROM WEAR, SUCH AS RUBBING ON ADJACENT PARTS OR STRUCTURE AND NO CORROSION WAS PRESENT. THIS REPAIR STATION IS UNSURE OF WHAT CAUSED THE DAMAGE TO THE CABLE.