An arrival burst of long-haul international flights tends to occur just after the curfew ends at 6am.

Heavy jets, especially those flying long-haul routes, require the use of the westernmost parallel runway for landing, (Runway 16 Right), because it is the longest runway.  The extra length is needed for a safe landing.  For this reason residents in suburbs around the flight path to this runway are likely to notice increased movements in the hour immediately after the curfew.