problem!
you can't access the CMC when the acft is below 10,000ft agl (at least not on ours).
even so, i dont think it is procedurally correct to access the CMC. i think Plastic Penguin has it right. the way the system indications were designed, there shouldn't require any messing with the CMC. all necessary indication will be presented on the instrument displays.
dutchman, once you have everything sorted out, for ADDITIONAL info (if required), CMC MAY be referred (absolutely no mention of CMC in boeing's procedures, just my own idea). but it must not be used as a primary indication source for your malfunction.
also, accessing CMC by an unfamiliar crew member may distract him/her from their primary duties of providing support to handling pilot as well as monitoring the flight path.
SR