What was found
HNL/KOA - FLT 86 - PILOT REPORT, LOUD BANG AND YAW PASSING 9,000 FEET AFTER TAKEOFF. ENGINE INSTRUMENTS LOOK NORMAL. RETURNED TO HNL. VISUALLY INSPECTED BOTH ENGINES, FUSELAGE, AND CONTROL SURFACES. NO VISUAL DEFECTS NOTED. EXERCISED FLIGHT CONTROLS AND VERIFIED CONTROL SURFACE MOVEMENT. ACCOMPLISHED RUN-UP OF BOTH ENGINES. ALL PARAMETERS NORMAL. OK FOR SERVICE. (X)