Because the MD-11 is no longer in production, finding the official, current FCOM can be challenging. However, several sources are popular among the simulation community:
Historically, McDonnell Douglas—and later Boeing, following the merger—organized the MD-11 FCOM into distinct volumes to make the massive amount of technical data easily digestible for flight crews. Volume 1: Systems and Equipment md11 fcom pdf
Volume III of the FCOM provides exhaustive descriptions of every major system: Because the MD-11 is no longer in production,