What was found
LEFT UPPER FUSELAGE SKIN CRACKED AT FIRST FASTENER BELOW STRINGER 2L ON FRAME 75, CRACK IS APPROXIMATELY 1/4" LONG. EASI 8071 USED, FREQ.=400 KHZ, V-GAIN=77.0, H-GAIN=64.0 LPF=100, 100-500 KHZ PROBE. SEE NTRC E460796 FOR WORK ACCOMPLISHED. REPAIR COVERED IN ETD2015-145-014350.