What was found
ON DEPARTURE CLIMB AT 1500' AGL LEFT ENGINE GAVE A LOUD BANG FOLLOWED BY A CONTINUAL SLAPPING SOUND. ENGINE GAUGES INDICATED OVER TEMP AND TORQUE RED WARNING LIGHT ILLUMINATED. SHUT ENGINE DOWN PER NON NORMAL CHECKLIST. RETURNED TO RST. PERFORMED BOROSCOPE OF LT ENGINE COMPRESSOR AND HOT SECTION. NO DEFECTS NOTED. DOWNLOADED FDR, FOUND A/I VALVE STUCK. REPLACED A/I VALVE AND PERFORMED GPA RUNS ON LT AND RT ENGINES. ALL RUNS AND LEAK CHECKS GOOD.