Originally Posted by
Skipness One Echo
Departing Garuda B77W was at 2000 ft by Wraysbury reservoir heading for CGK. Phillipines B77W for MNL 1000ft at same point. Low heavies tend to B787s which are the quietest of long haul but derate their take offs.
All LHR departures are subject to the "1,000 ft rule" which dictates that they must be at least 1000' AAL by the time they reach a point 6.5 km from the start of the takeoff roll. That's roughly overhead the original noise monitors, most of which (on 27s) are along the western edge of Wraysbury Reservoir.