What was found
RT ENGINE SURGE DURING CRUISE WITH LIGHT TURBULENCE AT FL380. EPR DROPPED .20 & N1 10 PERCENT. NO YAW FELT OR AUDIBLE STALL. PARAMETERS RECOVERED AND ARE NORMAL NOW IN SMOOTH AIR. NO EICAS MSGS. REFER TO FAULT CODE 71-05-21-02. CHECK IAW FIM. COMPLETED INSP EGT NOT EXCEEDED. NO METAL IN MCDS OR 14 AND 10 STAGE BLEED DUCTS. NO EPCS MSGS NOTED. ACCOMPLISHED BIRDSTRIKE, FOD INSP OF NR 2 FAN AREA, FOUND DAMAGE TO 1 EA FAN BLADE OUTER L/E. ACCOMPLISHED BOROSCOPE IAW AMM. REPLACED BLADES NR 3 AND NR 21 AND COMPLETED 5 MIN IDLE RUN. DAMAGE WAS BEYOND BLEND LIMITS.