AIM  8/15/19 (b) Oil Field Supervisors 3. Oil Field Supervisors (1) If presence of hydrogen sulfide is detected, a red rotating beacon or red high intensity strobe light adjacent to the primary helideck stairwell or wind indicator on the structure should be turned on to provide visual warning of hazard. If the beacon is to be located near the stairwell, the State of Louisiana “Offshore Heliport Design Guide” and FAA Advisory Circular (AC) 150/5390 − 2A, Heliport Design Guide, should be reviewed to ensure proper clearance on the helideck. (a) During venting of large amounts of unignited raw gas, a red rotating beacon or red high intensity strobe light adjacent to the primary helideck stairwell or wind indicator should be turned on to provide visible warning of hazard. If the beacon is to be located near the stairwell, the State of Louisiana “Offshore Heliport Design Guide” and FAA AC 150/5390 − 2A, Heliport Design Guide, should be reviewed to ensure proper clearance from the helideck. (2) Notify nearby helicopter operators and bases of the hazard and advise when hazard is cleared. (b) Notify nearby helicopter operators and bases of the hazard for planned operations. (c) Wind socks or indicator should be clearly visible to provide upward indication for the pilot. (3) Provide a safety briefing to include location of protective equipment to all arriving personnel. (4) Wind socks or indicator should be clearly visible to provide upwind indication for the pilot. 1. Background. Ignited flare booms can re- lease a large volume of natural gas and create a hot fire and intense heat with little time for the pilot to react. Likewise, unignited gas vents can release reasonably large volumes of methane gas under certain conditions. Thus, operations conducted very near unignited gas vents require precautions to prevent inadvertent ingestion of combustible gases by the helicopter engine(s). The following practices are recommended. 1. Background. A white “X” marked diago- nally from corner to corner across a helideck or heliport touchdown area is the universally accepted visual indicator that the landing area is closed for safety of other reasons and that helicopter operations are not permitted. The following practices are recommended. (a) Permanent Closing. If a helideck or heliport is to be permanently closed, X diagonals of the same size and location as indicated above should be used, but the markings should be painted on the landing area. h. Gas Venting Helideck/Heliport Operational Hazard Warning(s)/Procedures  −  Operations Near Gas Vent Booms i. Helideck/Heliport Operational Warn- ing(s)/Procedure(s)  −  Closed Helidecks or Heliports 2. Pilots (a) Gas will drift upwards and downwind of the vent. Plan the approach and takeoff to observe and avoid the area downwind of the vent, remaining as far away as practicable from the open end of the vent boom. (b) Do not attempt to start or land on an offshore helideck when the deck is downwind of a gas vent unless properly trained personnel verify conditions are safe. (b) Temporary Closing. A temporary marker can be used for hazards of an interim nature. This marker could be made from vinyl or other durable material in the shape of a diagonal “X.” The marker should be white with legs at least 20 feet long and 3 feet in width. This marker is designed to be quickly secured and removed from the deck using grommets and rope ties. The duration, time, location, and nature of these temporary closings should be provided to and coordinated with company aviation departments, nearby helicopter bases, and helicopter operators supporting the area. These markers MUST be removed when the hazard no longer exists.  (See FIG 10 − 2 − 2.) NOTE − White Decks: If a helideck is painted white, then international orange or yellow markings can be used for the temporary or permanent diagonals. 10 − 2 − 4 Special Operations