HMCS

Helmet Mounted Cueing System
Found on http://www.f-16.net/glossary-H.html

HMCS

Her Majesty's Court Service
Found on http://www.cjp.org.uk/glossary/

HMCS

Her Majesty's Canadian Ship (Canada)
Found on http://en.wikipedia.org/wiki/List_of_U.S._government_and_military_acronyms
No exact match found