What was found
CAPTAINS PFD, CAPTAINS MFD & EICAS WENT BLANK IN FLIGHT FOR 10 MINS. THEN PRD, MFD & EICAS WITH RED X. THEN PFD, MFD & EICAS BACK TO NORMAL AFTER 15 MINS. DECLARED EMER INBD DUE LOSS OF 3 PFDS? CLEARED ON LANDING. R & R IC 600 NR 1 IAW AMM 31-42-01. OPERATIONS CHECKED GOOD. REF ITEM 2 & 3 THIS AML FOR CAT II & RVSM.