What is the weight difference when refueling via gravity compared to pressure refueling?

When considering the weight difference between gravity refueling and pressure refueling, it is essential to understand the mechanics and practices involved in each method. Gravity refueling relies on the force of gravity to transfer the fuel from a tank to the aircraft's fuel system. This method can sometimes result in less efficient flow rates and potentially some fuel remaining in the transfer lines or tanks, leading to a situation where the aircraft ends up holding less fuel than it could when refueled under pressure.

In contrast, pressure refueling uses a pump to deliver fuel at a higher pressure, ensuring that fuel is moved more efficiently into the aircraft's tanks. This facilitates a quicker refuel and typically results in a near-complete fill of the aircraft's fuel capacity. Because pressure refueling optimizes the entire process, allowing for a more complete fill, it can result in additional weight being taken on by the aircraft.

In this scenario, the specific figure of 215 lbs accounts for the difference that may arise due to the more efficient fuel transfer and fill capacity associated with pressure refueling compared to gravity refueling. By achieving a full and advantageous fill, the pressure refueling method can harness that additional weight, whereas gravity refueling may leave some usable capacity unfilled, thus illustrating a