B757 CREW WAS REQUIRED TO SHUT DOWN #1 ENG AFTER EXPERIENCING COMPRESSOR STALLS.

Narrative

HEARD 2 BANGS FROM L ENG; FOLLOWED BY SPOOL DOWN TO SUB- IDLE RPM AND STEADILY RISING EGT. DECIDED TO SHUT DOWN ENG DUE STEADILY RISING TEMP. ACCOMPLISHED APPROPRIATE CHKLIST AND SHUT DOWN L ENG. CONTINUED TO PHL. LANDED SAFELY. ACCORDING TO MAINT; COMPRESSOR STALLS WERE CAUSED BY DEFECTIVE ELECTRONIC BLEED VALVE AIR CONTROLLERS. I WOULD LIKE TO SEE MECHANICAL SYS WHICH ARE CTLED BY ELECTRONIC CONTROLLERS BE DESIGNED SUCH THAT A FAILURE OF THE CONTROLLER WOULD RESULT IN THE SYS RETURNING TO A 'FAIL SAFE' MODE; ALLOWING AT LEAST SOME LEVEL OF CONTINUED OP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR WAS FLYING A B757 ACFT EQUIPPED WITH ROLLS ROYCE RB211-535 ENGS. MAINT TOLD THE PLT THAT THE 'ELECTRONIC BLEED VALVE SCHEDULE CONTROLLER' HAD FAILED. THIS CAUSED THE COMPRESSOR STALLS. THE ENG WENT TO A SUB IDLE CONDITION AS NOTED BY THE GENERATOR DROPPING OFF-LINE AND RISING EGT. THE PLT DOES NOT KNOW OF ANY OTHER ENG FAILURES IN THE 5 YRS ON THE ACFT OR 9 YRS AT HIS ACR.