3. Recommended Criteria (a) Minimum one-third rotor diameter clearance (1/3 RD). The landing helicopter maintains a minimum 1/3 RD clearance between the tips of its turning rotor and the closest part of a parked and secured helicopter (rotors stopped and tied down). (b) Three foot parking distance from deck edge (3"). Helicopters operating on an offshore helideck land or park the helicopter with a skid/wheel assembly no closer than 3 feet from helideck edge. (c) Tiedowns. Main rotors on all helicopters that are shut down be properly secured (tied down) to prevent the rotor blades from turning. (d) Medium (transport) and larger helicopters should not land on any offshore helideck where a light helicopter is parked unless the light helicopter is property secured to the helideck and has main rotor tied down. (e) Helideck owners/operators should ensure that the helideck has a serviceable anti-skid surface. 4. Weight and limitations markings on helideck. The helideck weight limitations should be displayed by markings visible to the pilot (see State of Louisiana "Offshore Heliport Design Guide" and FAA AC 150/5390-2A, Heliport Design Guide). NOTE- Some offshore helideck owners/operators have restrictions on the number of helicopters allowed on a helideck. When helideck size permits, multiple (more than two) helicopter operations are permitted by some operators. m. Helicopter Rapid Refueling Procedures (HRR) 1. Background. Helicopter Rapid Refueling (HRR), engine(s)/rotors operating, can be conducted safely when utilizing trained personnel and observing safe practices. This recommended practice provides minimum guidance for HRR as outlined in National Fire Protection Association (NFPA) and industry practices. For detailed guidance, please refer to National Fire Protection Association (NFPA) Document 407, "Standard for Aircraft Fuel Servicing," 1990 edition, including 1993 HRR Amendment. NOTE- Certain operators prohibit HRR, or "hot refueling," or may have specific procedures for certain aircraft or refueling locations. See the General Operations Manual and/or Operations Specifications to determine the applicable procedures or limitations. 2. Recommended Practices (a) Only turbine-engine helicopters fueled with JET A or JET A-1 with fueling ports located below any engine exhausts may be fueled while an onboard engine(s) is (are) operating. (b) Helicopter fueling while an onboard engine(s) is (are) operating should only be conducted under the following conditions: (1) A properly certificated and current pilot is at the controls and a trained refueler attending the fuel nozzle during the entire fuel servicing process. The pilot monitors the fuel quantity and signals the refueler when quantity is reached. (2) No electrical storms (thunderstorms) are present within 10 nautical miles. Lightning can travel great distances beyond the actual thunderstorm. (3) Passengers disembark the helicopter and move to a safe location prior to HRR operations. When the pilot-in-command deems it necessary for passenger safety that they remain onboard, passengers should be briefed on the evacuation route to follow to clear the area. (4) Passengers not board or disembark during HRR operations nor should cargo be loaded or unloaded. (5) Only designated personnel, trained in HRR operations should conduct HRR written authorization to include safe handling of the fuel and equipment. (See your Company Operations/Safety Manual for detailed instructions.) Special Operations 10-2-7