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transmissions, including those from helicopters. The following practices are recommended. 

## 2. Recommended Practices 

(a) Personnel Conducting Perforating Operations. Whenever perforating operations are scheduled and operators are concerned that radio transmissions from helicopters in the vicinity may jeopardize the operation, personnel conducting perforating operations should take the following precautionary measures: 

(1) Notify company aviation departments, helicopter operators or bases, and nearby manned platforms of the pending perforation operation so the Notice to Airmen (NOTAM) system can be activated for the perforation operation and the temporary helideck closure. 

(2) Close the deck and make the radio warning clearly visible to passing pilots, install a temporary marking (described in subpara- graph 10 − 2 − 1i1(b)) with the words “NO RADIO” stenciled in red on the legs of the diagonals. The letters should be 24 inches high and 12 inches wide. (See FIG 10 − 2 − 1.) 

(3) The marker should be installed during the time that charges may be affected by radio transmissions. 

(1) When operating within 1,000 feet of a known perforation operation or observing the white X with red “NO RADIO” warning indicating perforation operations are underway, pilots will avoid radio transmissions from or near the helideck (within 1,000 feet) and will not land on the deck if the X is present. In addition to communications radios, radio transmissions are also emitted by aircraft radar, 

## (b) Pilots 

<img src='content_image/532739.jpg'>

transponders, ADS − B equipment, radar altimeters, and DME equipment, and ELTs. 

(2) Whenever possible, make radio calls to the platform being approached or to the Flight Following Communications Center at least one mile out on approach. Ensure all communications are complete outside the 1,000 foot hazard distance. If no response is received, or if the platform is not radio equipped, further radio transmissions should not be made until visual contact with the deck indicates it is open for operation (no white “X”). 

## g. Hydrogen Sulfide Gas Helideck/Heliport Operational Hazard Warning(s)/Procedures 

1. Background. Hydrogen sulfide (H$_{2}$S) gas: Hydrogen sulfide gas in higher concentrations (300 − 500 ppm) can cause loss of consciousness within a few seconds and presents a hazard to pilots on/near offshore helidecks. When operating in offshore areas that have been identified to have concentrations of hydrogen sulfide gas, the following practices are recommended. 

## 2. Recommended Practices 

(1) Ensure approved protective air packs are available for emergency use by the crew on the helicopter. 

(2) If shutdown on a helideck, request the supervisor in charge provide a briefing on location of protective equipment and safety procedures. 

(3) If while flying near a helideck and the visual red beacon alarm is observed or an unusually strong odor of “rotten eggs” is detected, immediately don the protective air pack, exit to an area upwind, and notify the suspected source field of the hazard. 

## (a) Pilots 

