What was found
AIRCRAFT WAS GROUNDED: AN EMERGENCY WAS DECLARED DUE TO: ON CLIMB OUT THROUGH APPROXIMATELY 11000 FEET WITH CLIMB POWER ON BOTH ENGINES THE AIRCRAFT SHOOK MOMENTARILY WITH A BRIEF YAW TO THE LEFT. SOON AFTER FLIGHT ATTENDANTS CALLED AND SAID A BRIEF FLAME WAS VISIBLE ON LEFT SIDE. ENGINE NUMBER 1 HAD A COMPRESSOR STALL. AIRCRAFT AIR INTERRUPTED BACK TO AND LANDED SAFELY AT ORD. **SUPPLEMENTAL REPORT WILL BE SUBMITTED**(OPEN).