What was found
DURING THE 100 HOUR INSPECTION, WHILE COMPLETING STEP 13A OF THE AFT FUSELAGE/TAILBOOM AREA SECTION OF 05-11, THE UPPER LT ATTACH FITTING WAS SUSPECTED OF BEING CRACKED. THE PAINT WAS REMOVED FROM THE FITTING AND THE AREA SUBJECTED TO DYE-PENETRANT INSPECTION. A CRACK WAS REVEALED THAT RAN BETWEEN TWO RIVET HOLES AND THE LOWER EDGE OF THE ATTACH FITTING. THE AIRCRAFT IS PRIMARILY USED FOR POWER LINE PATROL AND OCCASIONAL REPETITIVE LIFT EXTERNAL LOAD OPERTAIONS. PROBABLE CAUSE: UNK