4.0 Landing Area Surface

  4.1 The landing area should have an overall coating of non-slip material and all markings on the surface of the landing area should be made with the same non-slip materials. Whilst extruded section or grid construction aluminium (or other) decks may incorporate adequate non-slip profiles in their design, it is preferable that they are also coated with a non-slip material unless adequate friction properties have been designed into the construction. It is important that the friction properties exist in all directions. Overpainting friction surfaces on such designs may compromise the friction properties. Recognised surface friction material is available commercially.

  4.2 Helicopter landing areas should be cambered to a maximum gradient of 1:100. Any distortion of the helicopter landing area surface due to, for example, loads from a helicopter at rest should not modify the landing area drainage system to the extent of allowing spilled fuel to remain on the deck. A system of guttering should be provided around the perimeter to prevent spilled fuel from falling on to other parts of the vessel and to conduct the spillage to an appropriate drainage system.

The capacity of the drainage system should be sufficient to contain the maximum likely spillage of fuel on the deck. The calculation of the amount of spillage to be contained should be based on an analysis of helicopter type, fuel capacity, typical fuel loads and uplifts. The design of the drainage system should preclude blockage by debris. The helicopter landing area should be properly sealed so that spillage will only route into the drainage system.

  4.3 For operations in adverse weather conditions a tautly-stretched rope netting should be provided to aid the landing of helicopters with wheeled undercarriages. The intersections should be knotted or otherwise secured to prevent distortion of the mesh. It is preferable that the rope be 20 mm diameter sisal, with a maximum mesh size of 200 mm. The rope should be secured every 1.5 metres round the landing area perimeter and tensioned to at least 2225 N. Netting made of material other than sisal may be considered but netting should not be constructed of polypropylene type material which is known to rapidly deteriorate and flake when exposed to weather. As a rule of thumb, it should not be possible to raise any part of the net by more than approximately 250 mm above the helicopter landing area surface when applying a vigorous vertical pull by hand. The location of the net should ensure coverage of the area of the aiming circle but should not cover the helicopter landing area identification marking or 't' value markings. Some nets may require modification to outboard corners so as to keep the identification marking uncovered. In such circumstances the dimensions given in Table 2 below may be modified.

  4.4 There are three sizes of netting as listed below in Table 2. The minimum size depends upon the type of helicopter for which the landing area is to be used as indicated in Table 1. Sizes are presented here for guidance only and nets of other sizes may be acceptable providing arrangements cover the whole of the aiming circle without obscuring the landing area identification markings.