What was found
BWI - FLT 2697 - AFTER A NORMAL TAKEOFF, ON CLIMB-OUT FROM BWI, THE NR 1 ENGINE SURGED THREE TO FOUR TIMES. CREW ACCOMPLISHED ENGINE STALL CHECKLIST AND OPERATED THE NR 1 ENGINE WITH REDUCED THRUST. THE NR 1 ENGINE RESPONDED TO THROTTLE REDUCTION. CREW DECLARED AN EMERGENCY AND RETURNED TO FIELD AT BWI. FLIGHT LANDED WITHOUT FURTHER INCIDENT. THE NR 1 ENGINE WAS NOT SHUT DOWN IN FLIGHT BUT OPERATED AT REDUCED THRUST. MAINTENANCE PERFORMED BOROSCOPE INSPECTION OF NR 1 ENGINE 13TH STAGE COMPRESSOR AND FOUND DAMAGE BEYOND MM LIMITS. BOROSCOPE INSPECTION FAILED. REMOVED AND REPLACED THE THE NR 1 ENGINE ASSEMBLY PER JOB CARD J271-00-01. OPERATIONAL CHECK AND LEAK CHECK GOOD. (M)