I would recommend you are at the gate and checked in for the flight NLT 75 minutes (90 would be better), or you may run across a TSA passenger list limitation. Even though you are going as an ACM (XCM or whatever), you are not on the crew list sent through the TSA, you are on the passenger list. the passenger list gets sent between 45 -60 minutes prior to departure. If you are not checked in prior to that list being sent you cannot get on that flight....per TSA rules.

Just a heads up.