What was found
SHIP 3242 DISC: DURING CRUISE @FL370, ATC GAVE US A SPEED REDUCTION, AS THE ENGINES DECREASED THRUST WE NOTICED ENG #1 VIB @ 2.2, AIRFRAME VIBRATIONS ANS FA'S REPORTED A "LOUD BANG". C/A: T/S PER A320 TSM 73-00-00-810-866-A R/R ENG #1 IP CHECK VALVE. ENG RAN AND NO LEAKS NOTED PER A320 AMM 36-11. PER ENG SPECIALIST FWD TO TSS FOR MONITORING. (LP: 6869468)