SAPA [Do KambhampatiDo Kambhampati2003] is a forward search planner using a relaxed temporal plan heuristic (based on the use of a relaxed TGP-style [Smith WeldSmith Weld1999] plan graph) to guide its search. The heuristic is supplemented with a heuristic estimate of resource usage allowing the planner to handle metric quantities. Temporal structure is managed using delayed effects, so that, when a durative action is executed, its end effects are queued in an event queue, pending application when time is advanced to the point at which they are triggered. The focus of SAPA development has been in the management of metric and temporal structure. SAPA did not attempt to compete in STRIPS or SIMPLETIME problems, but performed well in the more complex problems.