As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: AT LEVEL OFF ENGINE NUMBER 1 EXPERIENCED HARD SHUDDER AND N1; DROP OF 25% FOR APPROXIMATELY 4 SECONDS. ALSO, NOTICED A 500 LB IMBALANCE SUDDENLY WITH LEFT TANK LOW. AIRCRAFT EMERGENCY LANDED SAFELY AT MSY. TROUBLESHOT ENGINE NUMBER 1 PER FIM TASK 71-05-00-810-805-F00. FOUND HMU TO BE DEFECTIVE, REMOVED AND REPLACED HMU, PER WC 08L40073001. OPS CHECK AND LEAK CHECK GOOD.