diff --git a/qt-ui/diveplanner.cpp b/qt-ui/diveplanner.cpp
index 32e957363..b4ca5ba89 100644
--- a/qt-ui/diveplanner.cpp
+++ b/qt-ui/diveplanner.cpp
@@ -1445,6 +1445,8 @@ void DivePlannerPointsModel::createTemporaryPlan()
 		copy_samples(tempDive, current_dive);
 		copy_events(tempDive, current_dive);
 	}
+	// throw away the cache
+	free(cache);
 #if DEBUG_PLAN
 	dump_plan(&diveplan);
 #endif