The present disclosure relates generally to aircraft and, more specifically, to in-flight refueling of an aircraft.
At least some known aircraft are capable of being refueled while in flight. In-flight refueling is a strategic operation that enables an aircraft to increase its flight range and its effectiveness when it may not be feasible to land for refueling. In-flight refueling generally requires a supplying aircraft (e.g., a tanker) to maintain a substantially constant flight path, and a receiving aircraft (e.g., a fighter, a bomber, or a transport) to maneuver into a refueling envelope positioned behind and below the supplying aircraft.
In one known method of in-flight refueling, a probe-and-drogue system is used. In such a system, the supplying aircraft extends a fuel hose and an associated drogue therefrom, and the receiving aircraft maneuvers to enable a probe extending from the aircraft to mate with the drogue. During such operations, a closure rate of the receiving aircraft relative to the supplying aircraft is controlled to ensure a solid connection is formed between the probe and drogue. However, during low-light conditions, it may be difficult for the pilot of the receiving aircraft to accurately determine the closure rate and position of the receiving aircraft relative to the supplying aircraft.
In low-light conditions, visible light sources such as light bulbs, black lights, and/or fiber optics may be used to illuminate the exterior of the supplying aircraft. Such limited lighting facilitates the pilot of the receiving aircraft to determine a position of the receiving aircraft relative to the supplying aircraft. However, such lighting systems require wiring, housings, and power sources, for example, to function. Visible light sources may also be detectable to persons on the ground, thereby precluding in-flight refueling during a covert operation. Furthermore, such light sources may interfere with the cockpit lighting and/or decrease the dark-adapted vision of the pilot. For example, pilots often use night visions goggles (NVG) or night vision imaging systems (NVIS) when operating in low-light conditions. Visible light sources may emit infrared energy, which may create a light bloom when viewed through NVG. The light bloom may damage night vision equipment by oversaturating the night vision sensors. Further, when using a light source that is compatible with night vision goggles, the light may not be bright enough to sufficiently illuminate the drogue.