What was found
LOUD AIR NOISE AND SURGE DURING TAKEOFF AND LANDING. ON ARRIVAL INBOUND CREW REPORT LEFT ENGINE GOT NOISE AND SURGE DURING TAKEOFF AND DESCENT, CHECKED NO PL FAULT, NO EXISTING FAULT, NO FAULT HISTORY, AND NO EXCEED INDICATION. BOTH ENGINE RUN UP, CHECKED BLEED AIR NORMAL, NO ABNORMALITIES FOUND.