What was found
AT FL270 F/A NOTIFIED US OF SMOKE /FUMES /STRONG BURNING ODOR. SMOKE PREVALENT AT OVERWING EXITS ROW 24 TO 27. ODOR MOVED FORWARD TO COCKPIT. SMOKE COMING OUT OF ALL AIR VENTS IN MAIN AND FIRST CLASS CABIN. CABIN FULL OF SMOKE FOR 3-5 MINS. C/W STEPS 1-4 OF OPN 5088 BORESCOPED NR 1 AND 2 ENGINES NR 3 CARBON SEAL. NO LEAKS FOUND. COMPLETED OPN 5088, NO EVIDENCE OF SMOKE OR FUMES DURING OPN 5088. PERFORMED VERIFICATION FLT, NO ABNORMALITIES.