When should LDG flaps be used for landing?

Using LDG flaps for landing is particularly advantageous when the aircraft is heavy, and the landing distance required without flaps would exceed the available runway length. The scenario detailed in the correct answer indicates that when the landing distance with flaps up reaches or surpasses 80% of the available runway, deploying LDG flaps becomes essential. This helps ensure that the aircraft can safely land within the available distance by enhancing lift and drag at lower speeds, thereby reducing the landing rollout distance and improving safety margins.

In contrast, the other options do not capture the specific operational considerations that dictate the use of LDG flaps during landing. For example, stating that LDG flaps should be used for all landings disregards circumstances where flap use may not be necessary, depending on the aircraft's weight and the runway length. Additionally, suggesting the use of LDG flaps only when landing speeds exceed 150 knots ignores the aerodynamic benefits flaps provide in a broader range of landing situations. Finally, limiting flap use to simulated emergencies does not account for routine operations where flap utilization is crucial for performance and safety. Each of these considerations emphasizes the importance of adapting flap usage to situational needs rather than applying a blanket policy.