What was found
(CAN) ON DESCENT INTO YEG THE NR 1 ENGINE OIL PRESSURE BEGAN FLUCTUATING BETWEEN 0-35 PSI. IMMEDIATELY FOLLOWING THIS INDICATION THE LOW OIL PRESSURE BYPASS LIGHT ILLUMINATED. ENGINE WAS SHUT DOWN. TROUBLE SHOOTING REVEALED RESTRICTOR GOING TO OIL PRESSURE INDICATION SYSTEM FAILED. ALSO REPLACE OIL PRESSURE RELIEF VALVE. THE ENGINE WAS GROUND RUN AT HIGH POWER SETTING FOR 45 MINUTES WITH NO FURTHER INDICATIONS PROBLEMS. THE AIRCRAFT HAS OPERATED FROM YEG TO YWG TO YHM TO YWG WITHOUT ANY FUTHER PROBLEMS. THE COMPANY HAS CONSIDERED IT A DEFINITE FIX..