Believe it or not, I have spent many years reading the word 'equiptment' in pupils' work.
I teach Food (and 'every teacher is also a teacher of English' or bloody ought to be) and have gone beyond despair over this. In the end I reasoned that it has something to do with saying 'equipped' and their brains inserting some sort of misplaced logic.
I thought I just had dozy kids to start with but years down the line they're still doing it... and I'm still beating it out of them correcting it.
They also have a tendency to use 'electric whiskers' which always makes me laugh.