B737-200 CREW HIT A PLASTIC SHEET WHICH CAUSED AN ENG COMPRESSOR STALL ON CLBOUT AT STL.

Narrative

ON DEP PASSING 15000 FT; WE FELT A JERK -- AS IF SOMETHING HIT THE L SIDE OF THE ACFT OR THE L ENG STALLED. THE L ENG EGT WAS SLIGHTLY HIGHER THAN THE R; WITHIN LIMITS AND STABLE. ALL OTHER INDICATIONS WERE NORMAL. ON RETURN TO STL; AN EMER WAS DECLARED DUE TO THE UNKNOWN NATURE OF THE PROB. ON THE ARR TO STL; THE L EPR WAS ZERO WITH THE THROTTLE AT IDLE. OTHER ENG; THE EPR WAS NORMAL AS THROTTLE WAS ADVANCED. AN UNEVENTFUL APCH AND LNDG WERE MADE USING PRECAUTIONARY SINGLE ENG FLAPS 15 DEGS ENG FAILURE CHKLIST PROCS. AFTER LNDG; THE FIRE EQUIP CHKED US OVER AND WE TAXIED TO THE GATE. INSPECTION OF THE L ENG REVEALED A PLASTIC/NYLON SUBSTANCE IN THE INTAKE/BLADES/EXHAUST AREA. ALL OF THE SUBSTANCE WAS REMOVED BY A QUALIFIED MECH AND THE ENG RAN TO TKOF PWR IN A REMOTE LOCATION AT STL WITH THE FLC AND MECH ON BOARD. NO ABNORMALITIES WERE NOTED AND THE ACFT RETURNED TO SVC BY THE MECH. STL DEP/APCH DID AN OUTSTANDING JOB HANDLING OUR EXPEDITIOUS RETURN. THEY KEPT US ON A SINGLE FREQ FOR THE LAST PART OF THE APCH AND LNDG WHICH IS AN OUTSTANDING SVC.