Are you required to make another bracha on your tefillin if you take them off to check the parshios?
The Biur Halacha says you must make a new beracha because since you make the tefilin invalid in the process of checking the parshiyos this is considered a hefsek (interruption) in the mitzvah.
With tefilin, if you had in mind when putting them on that you might be taking them off and later putting them back on; then as long as you weren't in a situation in the middle that you COULDN'T have worn tefilin, the original bracha covers it.
So bathroom breaks require a new bracha. If you took them off for five minutes to help carry suitcases, you wouldn't need a new bracha.
Certainly wherever you're checking your tefilin is a place where tefilin can be worn; but I wonder if there's enough of a pause and concentration needed to open and check tefilin if you can still have that in mind. But in theory yes.