[...]
The outer surface, shown on Repulse Bay Airport Zoning Plan No. E.2846 dated April 23, 1990, is an imaginary surface located at a common plane established at a constant elevation of 45 m above the elevation of the airport reference point, except that, where that common plane is less than 9 m above the surface of the ground, the outer surface is an imaginary surface located at 9 m above the surface of the ground.
[...]