air-to-air refueling (aar) has been commonly used in military jet applications. recently, civilian applications of aar have been garnering increased attention due to the high cost of air travel, which is largely dictated by the cost of jet fuel. there are two types of aar approaches: probe-drogue and flying boom systems. this work explores the probe-drogue aar system in commercial applications. typical aar applications deploy a drogue connected to a long flexible hose behind a moving aircraft tanker. the drogue is connected to a probe in a receiver aircraft before initiating fuel transfer and is retracted back into the tanker when the fuel transfer is completed. in order to ensure a safe and efficient refueling operation sophisticated systems need to be developed to accommodate the turbulences encountered, particularly in respect to vibration reduction of the flexible hose and drogue. the objective of this work is to develop a probe-drogue system for helicopter aar applications. the first project is to make a preliminary design of a new aar system for helicopter refuelling from a modified at-802 tanker aircraft. [...]