13.3.1 The helicopter deck should be free of projections
except that landing lights or other essential projections may be installed
around the periphery of the deck provided they do not rise more than
15 centimetres above the level of the helicopter deck.
13.3.2 The helicopter deck should have recessed
tie-down points for securing a helicopter.
13.3.3 The helicopter deck should be protected
by a safety net at least 1.5 metres wide. The outer edge should not
rise more than 15 centimetres above the edge of the deck.
13.3.4 The helicopter deck should have both a
main and an emergency personnel access route located as far apart
from each other as practicable.