What was found
SHORTLY AFTER TAKEOFF AT 4,000 FEET, GOT A- LOOP ON RT ENGINE. INDICATED NORMAL. TWENTY SECONDS LATER, B-LOOP ILLUMINATED WITH BELL. EGT WAS 50 DEGREES HIGHER. PULLED THROTTLES BACK AND ALL LIGHTS AND BELL EXTINGUISHED. FOUND COWL A/I DUCT BLOWN ON TOP OF ENGINE AT COWL VALVE. REPLACED COWL VALVE AND DUCT ASSY. LEAK CKS GOOD. ENGINE TOTAL CYCLES 12,907.