Lindsay Lohan -- No Sleep in Brooklyn ... I've Got a Non-Stop Community Service Plan

Lindsay Lohan has a master plan to complete her community service and dodge, once again, a possible jail sentence -- the only problem is she's gone off the radar, and time is NOT on her side.

Sources close to Lohan tell us she's heading to the Brooklyn Community Center to log 6 hours a day, 7 days a week until her hearing on May 28. Sounds great, but -- as usual -- there are a few holes in this Lohan plan.

We did the math, and Linds would end up doing 114 hours. She needs 125 minus the hours she's already done -- 9 hours and 45 minutes ... and even that is suspect. But assuming best case scenario -- she'd be in the neighborhood.

However, she's currently M.I.A. in London. The 114 hours presumes she started TODAY, but we're told friends and family can't get in touch with her -- and all they know is ... she is NOT at the Brooklyn Community Center.

We're told Michael Lohan is already trying to set her up at rehab centers in NY to get additional hours, but that would still need approval from a judge.

Our sources say LiLo is hoping for leniency if she comes up just a few hours short by the deadline, but everyday she's not logging hours ... makes it less likely she'll even be close to the required hours.