What was found
AT TOP OF DESCENT FL280, THE NR 1 ENGINE EXPERIENCED A COMPRESSOR STALL WITH EGT RISING TO 900C. THE ENGINE WAS SHUT DOWN AND TWO RESTART ATTEMPTS WERE UNSUCCESSFUL. MAINTENANCE INSPECTED THE ENGINE PER MM 71-00-00 FOR TOP OF DESCENT STALL WITH NO DEFECTS NOTED. NUMEROUS COMPRESSOR BLEED CONTROL PARTS WERE CHANGED AND SUBSEQUENT ENGINE RUN WAS NORMAL. EXACT PART CAUSING PROBLEM TO BE DETERMINED.