Subpart G - Water aerodrome obstacle restriction and removal
139.151 Water aerodromes general
The following criteria define the airspace around a water aerodrome that shall be maintained free from obstacles. This shall be achieved by establishing a series of obstacle limitation surfaces that define the upper limits of permissible objects.
139.153 Water aerodrome Obstacle Limitation Surfaces
(a) A take-off climb surface and an approach surface shall be established in the direction of take-off or landing for each manoeuvring area, with the elevation of the inner edges of both surfaces equal to the ARE. The inner edges of the take-off climb surface and an approach surface originate at a distance of 30 m from the appropriate edges of a code W1 manoeuvring area, and 60 m from the appropriate edges of code W2 and W3 manoeuvring areas, and slope upwards and outwards until reaching their limiting distance.
(b) The take-off climb surface and an approach surface for a code W1, W2 and W3 omnidirectional manoeuvring area shall form a continuous surface surrounding the manoeuvring area and be equal to the corresponding length and slope dimensions for land-based runway code numbers 1, 2 and 3 respectively.
(c) The dimensions of the take-off climb surface and an approach surface relating to a code W1, W2 and W3 bi-directional manoeuvring area shall correspond to the dimensions for land-based runway code numbers 1, 2 and 3 respectively.
(d) The inner edge of the transitional surface is coincidental with the edge of the manoeuvring area in both elevation and position. It slopes upwards and outwards with distance from the manoeuvring area until it intercepts the plane of the inner horizontal surface.
(e) A transitional surface is not required for an omnidirectional manoeuvring area.
(f) An inner horizontal surface shall be established at a height of 45 m above the ARE, and shall be circular in shape radiating from the WARP to a distance of 2,000 m and 2,500 m for codes W1 and W2 manoeuvring areas respectively.
(g) The conical surface relating to codes W1 and W2 manoeuvring areas slopes upwards and outwards from the periphery of the inner horizontal surface in accordance with the criteria shown in Annex 14 Chapter 3 for the land-based runway code numbers 1 and 2 respectively.
139.155 Water aerodrome obstacle limitation requirements
(a) New objects or extensions of existing objects shall not be permitted above an approach or transitional surface except when, in the opinion of the Governor, the new object or extension would be shielded by an existing immovable object.
Figure 139.G.1 Water aerodrome Take-Off Climb, Approach and Transitional Surfaces for a Bi-directional Manoeuvring Area