qnli question: What do heavily laden aircraft sometimes require the assistance from? sentence: Another disadvantage is on mixed flight deck operations where helicopters are also present such as a US Landing Helicopter Dock or Landing Helicopter Assault amphibious assault ship a ski jump is not included as this would eliminate one or more helicopter landing areas, this flat deck limits the loading of Harriers but is somewhat mitigated by the longer rolling start provided by a long flight deck compared to many STOVL carriers.