Final answer:
The question relates to adjusting the aircraft's reference landing speed (Vref) based on changes in gross weight, and a rule of thumb is to increase Vref by 1 knot for every additional 1000 pounds of weight.
Step-by-step explanation:
The question you're asking pertains to the calculation of reference landing speed (Vref) for an aircraft, which is based on the gross weight of the plane. Vref is adjusted as the weight of the aircraft changes, to ensure a safe landing speed that allows for adequate lift and control. While the exact increase in Vref per unit increase in weight can vary depending on the aircraft's model and specific aerodynamic characteristics, a commonly used rule in the aviation industry is the increase of Vref by 1 knot for every additional 1000 pounds of weight. Thus, Option 2: 1,000 pounds; 10 knots would be a simplified rule of thumb. However, this is highly contextual and specific to certain aircraft models, and the actual Vref adjustments should always be calculated according to the aircraft's operating manual or the guidance provided by the aircraft's manufacturer.