What was found
DURING THE 7,000 HOUR WING CARRY-THROUGH STRUCTURE INSPECTION AND WING BOLT REPLACEMENT, FOUND BOLT HEAD, WASHER, AND SPACER LYING IN BOTTOM OF SPAR. NOTED CORROSION BETWEEN PARTED SURFACES OF BOLT AND HEAD - SUSPECT CAUSE OF BOLT FAILURE. NOTE: AIRCRAFT EXCEEDED 7,000-HOUR INSPECTION. RECOMMEND AT LEAST PERIODICALLY REMOVING WING TIP CAPS AND LOOKING DOWN SPAR FOR DEFECTS. ACTT: 7,785.7 HOURS.