What was found
ENGINE FIRE R RED CAS INTERMITTENT - ON FINAL APPROACH AFTER GEAR EXTENSION RIGHT SIDE ENGINE FIRE ECAS ILLUMINATED WITH THE AURAL WARNING. THE EVENT LASTED FOR ONE CYCLE OF THE AURAL WARNING THEN WENT OUT. REPEAT WRITE UP. ////SIGN-OFF////REMOVED UPPER AND LOWER R/H COWLINGS. NOTED FIRE LOOP TOUCHING LOW PRESSURE BLEED AIR DUCT. ADJUSTED FIRE LOOP. RAN ENGINE. NOTED LEAK AT HIGH PRESSURE DUCT. REMOVED DUCT AND NOTED COUPLING WORN. REMOVED OLD AND INSTALLED NEW COUPLINGS P/N MVB64757-200 AND MVB64757-150. PERFORMED LEAK CHECK. LEAK CHECK GOOD. NO ENGINE FIRE LIGHT NOTED DURING RUNS. WORK DONE IAW 680A MM CH 36-10-25.