What was found
AFTER AIRBORNE PASSING APPROXIMATELY 2500 FEET DURING THE CLIMB OUT, WE NOTICED VIBRATION BEGIN ON THE AIRCRAFT. IT CONTINUED TO WORSEN AND STABILIZED WITH THE RIGHT ENGINE EVM SHOWING 4.8 AT CLIMB THRUST WHICH WAS ABOUT 85%. REFERENCING THE APPROPRIATE FCIF AND THE FM, WE WERE UNABLE TO AFFECT ANY EVM READING SO WE RETURNED TO ANCHORAGE AFTER COMPANY COORDINATION. R&R RH ENGINE FAN BLADE #8 REF MM 72-21-02-4. ALL TESTS AND VIB SURVEY PASSED REF JRH.