What was found
WHILE ON FLIGHT, IN VMC CONDITIONS AT APPROX 0620 AST FL 270 & AT MOUNTAIN INTERSECTION, EXPERIENCED MECHANICAL IRREGULARITIES OF THE RT ENG. INITIALLY THERE WAS A SLOW FLUCTUATION OF TQ, N1 & FF, JUST SUBSEQUENT TO ENCOUNTERING SOME MILD MOUNTAIN WAVE TURBULENCE. THIS HOWEVER WAS LESS THAN 10 SECONDS & THE RT ENG THEN RETURNED TO NORMAL PARAMETERS. APPROX 1 MIN & 30 SECONDS LATER THE FLUCTUATION RETURNED & QUICKLY DETERIORATED INTO AN TQ, N1 & FF ROLLBACK WITH AN ACCOMPANYING RAPID SPIKE IN ITT, AT WHICH TIME, EXECUTED THE ENG FAILURE IN FLIGHT EP. MAX ITT OBSERVED WAS 860 - 880 DEGREES. AFTER INFORMING ATC, REQUIRED LOWER ALTITUDE AFTER SHUTTING DOWN THE RT ENG CONTINUED FLIGHT IN VMC CONDITIONS WITHOUT ANY FURTHER IRREGULARITIES ON THE ACFT. ENG REMOVED & SENT TO AN OVERHAUL FACILITY FOR INSPECTION. REPORT WILL BE UPDATED PENDING RESULTS OF INSPECTION.