What was found
AFTER MLG RETRACTION, HEARD RAPID LOUD BANGS FOLLOWED BY A PAUSE, THEN ANOTHER RAPID LOUD BANGS. N1 LT ENG DROPPED FROM CLIMB POWER TO APPROX 62.7% DURING BANGS, RETURNED TO NORMAL WHEN CEASED. TOWER STATED BANGS WERE HEARD WITH A MOMENTARY FIREBALL FROM LT ENG. NO SECONDARY INDS & RETURNED TO LAND W/ NORMAL CHKLSTS. AFTER LANDING, STOPPED ON RUNWAY TO ALLOW ARFF TO INSPECT. NO SIGNS OF LEAKS, SEEPING, OR SMOKING NOTED & TAXIED ACFT. REMOVED ENG & INSTALLED A REPAIRED ENG IAW LMM 72-00-00, SUBTASK 72-00-00-420-004-A01. PERFORMED POST ENG INSTALL LEAK & OPS CHK IAW LMM 72-00-00. POST ENG RUNS GOOD, NO DEFECTS. WORK DONE IAW LMM 72-05-22, REV 13, AND BD-100-1A10, TASK 71-00-01-400-801, REV 42.