UNDERWAY REPLENISHMENT NWP 4-01.4 - Historic Naval Ships ...

NWP 4-01.410.2.2.3 Ship-Produced Interference. It is moredifficult to conduct VERTREP when either the deliveryor receiving ship has another ship alongside that:1. Creates turbulent air or vents hot stack gas overthe helicopter pickup or drop area2. Blocks off the wind in the pickup or drop area3. Presents a physical obstruction to the desired flightpattern, necessitating a downwind approach ordeparture. Downwind approaches and departureswith an external load should be avoided.Helicopters with an external load shall notoverfly ships unless operational necessity sodictates.10.2.2.4 Temperature and Atmospheric Pressure.These factors affect the lift capability of helicopters.Any increase in temperature or decrease inatmospheric pressure will decrease maximum liftcapability. This loss in lift is a result of reduced engineperformance and reduced aerodynamic performance ofthe rotor blades. Thus, a cold, dry day with high barometricpressure and a strong, steady, relative wind isbest for VERTREP operations.10.2.2.5 Helicopter Pilot Fatigue. OPNAVINST3710.7 establishes guidelines for use by commandingofficers in determining the maximum number of hoursthat pilots can fly during any given period. During dayVERTREP, 6 to 8 hours are generally accepted as an effectivelimit of pilot endurance. During nightVERTREP, the effective limit per pilot may be reducedto as few as 2 to 3 hours (see paragraph 10.11.1.2). Factorsaffecting pilot endurance include:1. Deck pitch and roll2. Weather conditionsWARNING3. Aircrew experience/currency4. Number of hours without rest5. Night operations and reduced visibility.10.2.2.6 Helicopter Fuel Loading. A full fuelload adds substantial weight to the helicopter andthereby reduces the amount of cargo that can be lifted.As fuel is expended, more cargo can be lifted. Factorsto be considered in determining the fuel load are:1. Distances to be flown2. Amount of cargo to be transferred3. Meteorological conditions.When conditions are favorable for lifting heavyloads, more fuel generally can be carried.10.2.2.7 Number of Helicopters Used. Thenumber of helicopters used during a VERTREP operationwill depend on:1. Type and number of ships being replenished2. Distance between ships3. Number of helicopters available4. Ability of the receiving ship to keep the cargodrop area(s) clear5. Ability of the delivery ship to provide cargo at asufficient rate6. Administrative flights scheduled by the helicoptercoordinator7. Helicopter aircrew proficiency and trainingrequirements.10.3 HELICOPTER COORDINATORThe replenishment group commander will designatea helicopter coordinator to control and coordinate allhelicopters and VERTREP operations. Normally, thehelicopter coordinator will be the senior commandingofficer of the replenishment ship with VERTREP helicopter(s)embarked and participating in the operation.The helicopter coordinator will make appropriaterecommendations to the replenishment group commanderconcerning:1. Course for optimum relative wind for helicopteroperation2. Delivery ship position in the formation to shortenthe distance between transferring and receiving shipsto enhance VERTREP effectiveness without embarrassingor hazarding other ships in formation10-5 ORIGINAL