If your child is an adequate student, there's no reason why he/she can't miss school (as long as the missed work is done). If you can find out ahead of time, you might even be able to do the "make-up" work before you leave. The trip will be with him/her much longer than those days in school would be.
You probably do need to clear it with your school first. Many schools are very helpful in this type of situation, but some districts really try to make it hard on you to be out. They may like to sound like their primary interest is the education of your child, but they are also interested in funding which is attendance related (I spent several years in school administration).
Good luck!