Weight is a downwards force caused by the Earth's gravity acting on the mass of the plane.
(Weight; is; a downwards force caused by the Earth's gravity) (a downwards force; caused; by the Earth's gravity) (the Earth's gravity; acting; on the mass of the plane)
Weight a downwards force the Earth's gravity
is caused acting
a downwards force caused by the Earth's gravity
by the Earth's gravity
on the mass of the plane