The first reason is the view of Mt. Everest is blocked by other towering peaks Of Nuptse and Lhotse. Everest base camp do not have safe Helipad, due to movement of glaciers, as well danger of rock fall; and occasional avalanches. The other best reason is to save the fragile pristine environment. The sound of a chopper might create damage to the whole environment; we must follow the rules of Eco and Responsible Tourism.